PHOTO

Takayuki Narushima
Section
Graduate School of Engineering
Job title
Professor
Degree
  • 博士(工学)(東北大学)

Research History 7

  • 2023/04 - Present
    Research Center for Rare Earth and Green Innovation (RaMGI) Director

  • 2007/04 - Present
    東北大学大学院工学研究科材料システム工学専攻 教授

  • 2004/06 - 2007/03
    東北大学先進医工学研究機構 教授

  • 1997/04 - 2004/06
    東北大学大学院工学研究科 助教授

  • 1998/03 - 1999/03
    カリフォルニア大学(文部省在外研究員) リサーチフェロー

  • 1994/12 - 1997/03
    東北大学工学部 助教授

  • 1987/04 - 1994/11
    東北大学工学部 助手

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Education 2

  • Tohoku University Graduate School, Division of Engineering 材料物性工学専攻

    - 1987/03/31

  • Tohoku University Faculty of Engineering 金属工学科

    - 1985/03/31

Committee Memberships 33

  • The Iron and Steel Institute of Japan Representative

    2024/04 - Present

  • The Japan Society of Titanium vice president

    2021/04 - Present

  • The Japanese Society for Dental Materials and Devices Tohoku Branch Delegate

    2018/04 - Present

  • International Organization Committee , World Conference of Titanium Member (Japan)

    2015/08 - Present

  • JABEE Committee, The Iron and Steel Institute of Japan Member

    2015/04 - Present

  • The Japan Titanium Society Representative, Industry-university cooperation committee

    2010/04 - Present

  • The Japanese Society for Biomaterials Trustee

    2006/04 - Present

  • The Japan Institute of Metals and Materials Director

    2021/04 - 2023/03

  • The Japan Institute of Light Metals The Journal of the Japan Institute of Light Metals, Editorial committee, Member

    2010/04 - 2023/03

  • The Japanese Society for Biomaterials Director

    2012/04 - 2022/03

  • Japan Accreditation Board for Engineering Education Director

    2019/04 - 2021/04

  • JABEE Committee, The Iron and Steel Institute of Japan Chairman

    2018/04 - 2020/03

  • Japan Accreditation Board for Engineering Education 認定・審査調整委員会委員

    2018/04 - 2020/03

  • The Iron and Steel Institute of Japan Director

    2018/04 - 2020/03

  • 軽金属学会研究委員会「チタンの準安定相・析出相研究部会」 部会長

    2015/06 - 2020/03

  • The Japan Institute of Light Metals Chairman, Tohoku Branch

    2015/04 - 2019/03

  • Titanium Manufacturing Process and Materials Function Research Group, The Japan Institute of Metals and Materials Representative

    2014/04 - 2019/03

  • JABEE Committee, The Iron and Steel Institute of Japan Vice Chairman

    2016/04 - 2018/03

  • Bio and Healthcare Materials Division, The Japan Institute of Metals and Materials Vice Chairman

    2015/04 - 2017/03

  • 次世代構造部材創製・加工技術開発 総合技術委員会 Member

    2013/10 - 2016/03

  • Bio and Healthcare Materials Division, The Japan Institute of Metals and Materials Chairman

    2011/04 - 2015/03

  • The Japan Institute of Light Metals Director

    2011/04 - 2015/03

  • Editorial Committee, The Japan Institute of Light Metals Secretary, Editorial Committee

    2011/04 - 2015/03

  • Bio and Healthcare Materials Division, The Japan Institute of Metals and Materials Vice Chairman

    2009/04 - 2011/03

  • 日本金属学会分科会 幹事

    2005/04 - 2009/03

  • 日本金属学会 会誌・欧文誌 編集委員

    2002/04 - 2006/03

  • 日本金属学会分科会 委員

    2003/04 - 2005/04

  • 日本金属学会 会報「まてりあ」 編集委員

    2003/04 - 2005/03

  • (社)日本鉄鋼協会 ノーベルプロセッシングフォーラム幹事

    2000/04 - 2003/03

  • (社)日本鉄鋼協会 東北支部幹事

    2000/04 - 2002/03

  • 日本セラミックス協会 JABEE対応学部カリキュラム小委員会委員

    2000/10 - 2001/03

  • 日本金属学会 会報「まてりあ」 編集委員

    1999/04 - 2001/03

  • 日本金属学会 まてりあ改革検討小委員会委員

    2003/06 -

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Professional Memberships 9

  • The Japan Titanium Society

    2012/04 - Present

  • The Minerals, Metals & Materials Society (TMS)

    2010/01 - Present

  • The Japanese Society of Dental Materials and Devices

    2007/04 - Present

  • The Japan Institute of Light Metals

    2007/04 - Present

  • The Japanese Society for Biomaterials

    2005/04 - Present

  • The Iron and Steel Institute of Japan

    1990/04 - Present

  • The American Ceramic Society

    1989/01 - Present

  • The Japan Institute of Metals and Materials

    1987/04 - Present

  • The Ceramic Society of Japan

    1987/01 - Present

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Research Interests 5

  • interfacial reaction

  • calcium phosphate

  • Co-Cr-Mo alloys

  • titanium alloys

  • biomaterials

Research Areas 4

  • Nanotechnology/Materials / Structural and functional materials /

  • Life sciences / Biomaterials /

  • Life sciences / Biomedical engineering /

  • Nanotechnology/Materials / Material fabrication and microstructure control /

Awards 37

  1. ポスター賞

    2019/12 第2回日本金属学会第7分野講演会「金属系バイオマテリアルサイエンスの新展開(II)」 実用歯科用チタン合金表面に作製した炭素・窒素含有TiO2膜の可視光応答性評価

  2. 優秀ポスター賞

    2019/10 日本バイオマテリアル学会東北ブロック ステント用Co-Cr-W-Ni合金の結晶粒粒微細化と機械的特性

  3. 東北大学金属材料研究所共同研究ワークショップ・日本バイオマテリアル学会東北ブロック講演会 優秀ポスター賞

    2019/10 日本バイオマテリアル学会東北ブロック 二段階熱酸化によるチタンへの炭素・窒素含有TiO2膜の作製と可視光応答型光触媒活性

  4. 平成30年度軽金属希望の星賞

    2019/03 軽金属学会 二段階熱酸化法による実用Ti合金表面への光活性抗菌機能化TiO2膜作製と評価

  5. 東北大学金属材料研究所共同研究ワークショップ・日本バイオマテリアル学会東北ブロック講演会 優秀ポスター賞

    2018/08 日本バイオマテリアル学会東北ブロック 二段階熱酸化による歯科用Ti合金へのTiO2膜作製と抗菌能評価

  6. 東北大学金属材料研究所共同研究ワークショップ・日本バイオマテリアル学会東北ブロック講演会「バイオマテリアル研究 東北地区交流会」 優秀ポスター賞

    2017/09/26 バイオマテリアル研究 東北地区

  7. Poster Presentation Award

    2017/06/28 Joint Symposium on Materials Science and Engineering for the 21st Century

  8. Poster Presentation Award

    2017/03/21 2017 Annual Meeting of Excellent Graduate Schools for Materials Integration Center and Materials Science Center

  9. Poster Presentation Award

    2016/03/19 2016 Japan-Russia Joint Seminar “Advanced Materials Synthesis Process and Nanostructure” in conjunction with 2015 Annual Meeting of Excellent Graduate Schools for “Materials Integration Center” and “Materials Science Center”

  10. 優秀ポスター賞

    2015/09 日本金属学会

  11. 優秀ポスター発表賞

    2015/05 軽金属学会

  12. Best Oral Presentation

    2014/11 Bioceramics26

  13. 優秀ポスター賞

    2014/09 日本金属学会

  14. Award of the 2nd poster presentation prize

    2014/09 6th International Workshop on Advanced Ceramics

  15. Light Metal R&D Furtherance Medal

    2014/05/17 (一社)軽金属学会

  16. Outstanding Presentation Award

    2013/12 International Symposium on Eco Topia Science 2013(ISETS13)

  17. 優秀講演発表賞

    2013/05 粉体粉末冶金協会

  18. 日本セラミックス協会東海支部学術研究発表会 優秀発表賞

    2012/12 日本セラミックス協会東海支部

  19. The 29th Japan Titanium Society Meritorious Award

    2012/11/19 日本チタン協会

  20. ISAEM2012 Best Poster Presentation

    2012/11/06 ISAEM-2012

  21. Best Poster Award

    2009/12 KINKEN-WAKATE2009

  22. 第8回日本金属学会東北支部研究発表大会 奨励賞

    2009/12 日本金属学会東北支部

  23. Best Presentation Award

    2009/09 Interdisciplinary Science of Nanomaterials

  24. ISAEM-2008 Best Poster Presentation

    2008/11 ISAEM-2008

  25. 第10回日本金属学会優秀ポスター賞

    2008/03/26 日本金属学会

  26. 第66回日本金属学会功績賞

    2008/03/26 (社)日本金属学会 材料化学部門

  27. 第6回軽金属躍進賞

    2007/11/10 (社)軽金属学会 軽金属に関する学術研究および技術開発

  28. 第6回日本金属学会東北支部研究発表大会 ポスター優秀賞

    2007/11 日本金属学会東北支部

  29. 第一回東北大学金属材料研究所附属金属ガラス総合研究センター共同利用研究最優秀賞

    2007/05/21 東北大学金属材料研究所附属金属ガラス総合研究センター

  30. 平成19年度学術記念賞(西山記念賞)

    2007/03/27 (社)日本鉄鋼協会 材料製造プロセスの基礎的研究

  31. 傾斜機能材料研究会2006年度研究奨励賞

    2006/06 傾斜機能材料研究会

  32. 第5回日本金属学会優秀ポスター賞

    2005/09 日本金属学会

  33. 第1回日本金属学会優秀ポスター賞

    2003/10 日本金属学会

  34. 第5回金属学会奨励賞

    1995/12 (社)日本金属学会 新素材の高温における物理化学

  35. 第65回工学研究奨励賞

    1995/10 (財)服部報公会 ラマン分光法により高温酸化皮膜形成過程のその座観察

  36. 第34回原田研究奨励賞

    1994/07 (財)金属研究助成会 シリコン其セラミックスの高温酸化

  37. 第15回本多記念研究奨励賞

    1994/02 (財)本多記念会 シリコン其セラミックスの高温酸化

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Papers 260

  1. Systematic study on the microstructures of biomedical Co-20Cr-15W-10Ni alloys with carbon contents ranging from 0 to 0.2 mass pct Peer-reviewed

    S.S. Friandani, K. Ueda, T. Narushima

    Metall. Mater. Trans. B 55 1011-1024 2024/03

    DOI: 10.1007/s11661-024-07300-3  

  2. Improvement of Work-Hardening Behavior of Co-Cr-W-Ni Alloy by Adding Mn/Fe for Balloon-Expandable Stents Peer-reviewed

    Kosuke Ueki, Kyosuke Ueda, Masaaki Nakai, Takayoshi Nakano, Takayuki Narushima

    Key Engineering Materials 967 115-120 2023/12/05

    Publisher: Trans Tech Publications, Ltd.

    DOI: 10.4028/p-ervq7v  

    eISSN:1662-9795

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    The Co-20Cr-15W-10Ni (CCWN, mass%) alloy, registered as American society of testing and materials (ASTM) F90, has been widely used as a balloon-expandable stent because of its excellent balance between its mechanical properties and corrosion resistance. To realize a less invasive stent placement, the stent diameter must be reduced, which implies that the stent strut thickness must be reduced. As such, the CCWN alloy must be high in strength and ductility while maintaining a low yield stress to facilitate the expansion and suppression of stent recoil. In this study, we focus on the effects of the adding Mn/Fe on the microstructure, mechanical properties, and corrosive properties of CCWN alloys. A 6 mass% Mn-added CCWN alloy with a grain size of approximately 20 μm prepared in this study exhibits excellent balance between tensile strength and ductility. In addition, it exhibits a lower yield stress while maintaining a high tensile strength compared with the ASTM F90 alloy. Meanwhile, a 6 mass% Fe-added CCWN alloy exhibits a higher ductility compared with the ASTM F90 alloy. The addition of Mn or Fe to the CCWN alloy increases the stacking fault energy of the alloy and suppresses strain-induced martensitic transformation during plastic deformation, thus improving the ductility of the alloy. Results of polarization tests show that the 6 mass% Mn-or Fe-added CCWN alloys exhibit the same corrosion current density as the ASTM F90 alloy. Mn-added Co-Cr-W-Ni alloys are suitable for use in balloon-expandable stents.

  3. Visible-light antibacterial activity of carbon and nitrogen co-doped rutile TiO2 films Invited Peer-reviewed

    R. Koizumi, K. Ueda, K. Ito, K. Ogasawara, H. Kanetaka, T. Mokudai, T. Narushima

    Thin Solid Films 780 139944 2023/08

    DOI: 10.1016/j.tsf.2023.139944  

  4. Electronic structure analysis of light-element-doped anatase TiO2 using all-electron GW approach Peer-reviewed

    T. Ishikawa, R. Sahara, K. Ohno, K. Ueda, T. Narushima

    Comput. Mater. Sci. 220 112059 2023/02

    DOI: 10.1016/j.commatsci.2023.112059  

  5. Special Issue on Recent Research and Development in the Processing, Microstructure, and Properties of Titanium and Its Alloys

    Mitsuo Niinomi, Masahiko Ikeda, Yoko Yamabe-Mitarai, Hideki Hosoda, Takuya Ishimoto, Sengo Kobayashi, Takao Hanawa, Takayuki Narushima, Takayoshi Nakano

    Materials Transactions 64 (1) 1 2023

    DOI: 10.2320/matertrans.MPR2023901  

    ISSN:1345-9678

  6. Improvement of mechanical properties of Co–Cr–W–Ni alloy tube suitable for balloon-expandable stent applications through heat treatment Peer-reviewed

    Shunsei Takeda, Kosuke Ueki, Kyosuke Ueda, Masaaki Nakai, Takayoshi Nakano, Takayuki Narushima

    Materials Science and Engineering: A 862 144505-144505 2023/01

    Publisher: Elsevier BV

    DOI: 10.1016/j.msea.2022.144505  

    ISSN:0921-5093

  7. Effect of niobium and oxygen contents on microstructure and mechanical properties of α+β-type Ti-(5–25)Nb-(0.5–1)O (mass%) alloys for biomedical applications Peer-reviewed

    K. Ueda, M. Omiya, K. Kato, H. Kanetaka, T. Narushima

    Mater. Trans. 64 (1) 138-146 2023/01

    DOI: 10.2320/matertrans.MT-MLA2022020  

  8. Antibacterial properties of TiO2 layers formed by Au-sputtering and thermal oxidation of titanium under visible light Peer-reviewed

    T. Ueda, R. Koizumi, K. Ueda, K. Ito, K. Ogasawara, H. Kanetaka, T. Narushima

    Mater. Trans. 63 (12) 155-164 2023/01

    DOI: 10.2320/matertrans.MT-MLA2022006  

    ISSN:1345-9678

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    To prevent infection in dental implants using photocatalytic activity under visible-light irradiation, the fabrication of Au-added TiO2 layers on Ti substrates and their antibacterial properties were studied. Pure Au and Ti(60, 40) mol%Au alloy films with thicknesses of 1047 nm were sputtered onto Ti, followed by thermal oxidation in air at 873 K for 1.8 ks to form TiO2 layers. The antibacterial properties against Escherichia coli, cytotoxicity, and bonding strength to Ti substrates were evaluated. The highest antibacterial activity under visible-light irradiation was obtained when the sputtered film was pure Au and its thickness was 38 nm. Compared with as-polished commercially pure Ti, the number of viable mouse osteoblast-like cells and human gingival fibroblasts on Au-added TiO2 layers increased after placement in the dark but decreased after visible-light irradiation. The best antibacterial property-bonding strength balance was achieved when the Ti40 mol%Au sputtered film with a thickness of 42 nm was formed on Ti. To the best of our knowledge, this study is the first to report the formation of TiO2 layers with antibacterial activity under visible-light irradiation by combining Au-sputtering and thermal oxidation of Ti.

  9. Tough yet flexible superelastic alloys meet biomedical needs Invited Peer-reviewed

    X. Xu, T. Odaira, S. Xu, K. Hirata, T. Omori, K. Ueki, K. Ueda, T. Narushima, M. Nagasako, R. Kainuma, S. Harjo, T. Kawasaki, L. Bodnárová, P. Sedlák, H. Seiner

    Advanced Materials & Processes 180 (7) 35-37 2022/10

    Publisher: ASM INT

    ISSN:0882-7958

    eISSN:2161-9425

  10. Flexible and Tough Superelastic Co–Cr Alloys for Biomedical Applications International-journal Peer-reviewed

    Takumi Odaira, Sheng Xu, Kenji Hirata, Xiao Xu, Toshihiro Omori, Kosuke Ueki, Kyosuke Ueda, Takayuki Narushima, Makoto Nagasako, Stefanus Harjo, Takuro Kawasaki, Lucie Bodnárová, Petr Sedlák, Hanuš Seiner, Ryosuke Kainuma

    Advanced Materials 34 (27) 2202305-2202305 2022/07

    Publisher: Wiley

    DOI: 10.1002/adma.202202305  

    ISSN:0935-9648

    eISSN:1521-4095

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    The demand for biomaterials has been increasing along with the increase in the population of elderly people worldwide. The mechanical properties and high wear resistance of metallic biomaterials make them well-suited for use as substitutes or as support for damaged hard tissues. However, unless these biomaterials also have a low Young's modulus similar to that of human bones, bone atrophy inevitably occurs. Because a low Young's modulus is typically associated with poor wear resistance, it is difficult to realize a low Young's modulus and high wear resistance simultaneously. Also, the superelastic property of shape-memory alloys makes them suitable for biomedical applications, like vascular stents and guide wires. However, due to the low recoverable strain of conventional biocompatible shape-memory alloys, the demand for a new alloy system is high. The novel body-centered-cubic cobalt-chromium-based alloys in this work provide a solution to both of these problems. The Young's modulus of <001>-oriented single-crystal cobalt-chromium-based alloys is 10-30 GPa, which is similar to that of human bone, and they also demonstrate high wear and corrosion resistance. They also exhibit superelasticity with a huge recoverable strain up to 17.0%. For these reasons, the novel cobalt-chromium-based alloys can be promising candidates for biomedical applications.

  11. Analysis of the oxidation and nitridation of Ti-17 (Ti-5Al-2Sn-2Zr-4Mo-4Cr) alloys with added Si in atmospheric heating Peer-reviewed

    Narushima, S. Suzuki, K. Ueda, S.K. Bhattacharya, R. Sahara

    ISIJ Int. 62 (7) 1512-1521 2022/07

    DOI: 10.2355/isijinternational.ISIJINT-2022-053  

  12. Electronegativity difference as a descriptor for oxidation inhibiting effect of alloying element during early stages of titanium oxidation International-journal International-coauthorship Peer-reviewed

    K. Kohli, S. Bhattacharya, K. Ueda, T. Narushima, R. Sahara, P. Ghosh

    Langmuir 38 (4) 1448-1457 2022/01

    Publisher: American Chemical Society (ACS)

    DOI: 10.1021/acs.langmuir.1c02633  

    ISSN:0743-7463

    eISSN:1520-5827

  13. Development of Low-Yield Stress Co–Cr–W–Ni Alloy by Adding 6 Mass Pct Mn for Balloon-Expandable Stents Peer-reviewed

    Soh Yanagihara, Kosuke Ueki, Kyosuke Ueda, Masaaki Nakai, Takayoshi Nakano, Takayuki Narushima

    Metallurgical and Materials Transactions A 52 (9) 4137-4145 2021/07/07

    Publisher: Springer Science and Business Media LLC

    DOI: 10.1007/s11661-021-06374-7  

    ISSN:1073-5623

    eISSN:1543-1940

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    <title>Abstract</title>This is the first report presenting the development of a Co–Cr–W–Ni–Mn alloy by adding 6 mass pct Mn to ASTM F90 Co–20Cr–15W–10Ni (CCWN, mass pct) alloy for use as balloon-expandable stents with an excellent balance of mechanical properties and corrosion resistance. The effects of Mn addition on the microstructures as well as the mechanical and corrosion properties were investigated after hot forging, solution treatment, swaging, and static recrystallization. The Mn-added alloy with a grain size of ~ 20 <italic>µ</italic>m (recrystallization condition: 1523 K, 150 seconds) exhibited an ultimate tensile strength of 1131 MPa, 0.2 pct proof stress of 535 MPa, and plastic elongation of 66 pct. Additionally, it exhibited higher ductility and lower yield stress while maintaining high strength compared to the ASTM F90 CCWN alloy. The formation of intersecting stacking faults was suppressed by increasing the stacking fault energy (SFE) with Mn addition, resulting in a lower yield stress. The low-yield stress is effective in suppressing stent recoil. In addition, strain-induced martensitic transformation during plastic deformation was suppressed by increasing the SFE, thereby improving the ductility. The Mn-added alloys also exhibited good corrosion resistance, similar to the ASTM F90 CCWN alloy. Mn-added Co–Cr–W–Ni alloys are suitable for use as balloon-expandable stents.

  14. Effect of Precursor Deficiency Induced Ca/P Ratio on Antibacterial and Osteoblast Adhesion Properties of Ag-Incorporated Hydroxyapatite: Reducing Ag Toxicity Peer-reviewed

    Ozkan Gokcekaya, Celaletdin Ergun, Thomas J. Webster, Abdurrahman Bahadir, Kyosuke Ueda, Takayuki Narushima, Takayoshi Nakano

    Materials 14 (12) 3158-3158 2021/06/08

    Publisher: MDPI AG

    DOI: 10.3390/ma14123158  

    eISSN:1996-1944

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    Ag-containing hydroxyapatite (HA) can reduce risks associated with bacterial infections which may eventually require additional surgical operations to retrieve a failed implant. The biological properties of HA in such applications are strongly affected by its composition in terms of dopants as well as Ca/P stoichiometry, which can be easily controlled by altering processing parameters, such as precursor concentrations. The objective of this in vitro study was to understand the effect of variations in HA precursor solutions on antibacterial properties againstEscherichia coli(E. coli) and for promoting osteoblast (bone-forming cell) adhesion on Ag incorporated HA (AgHA) which has not yet been investigated. For this, two groups of AgHAs were synthesized via a precipitation method by adjusting precursor reactants with a stoichiometric value of 1.67, being either (Ca + Ag)/P (Ca-deficient) or Ca/(P + Ag) (P-deficient), and were characterized by XRD, FTIR, and SEM-EDS. Results showed that Ag+ incorporated into the Ca2+ sites was associated with a corresponding OH− vacancy. Additional incorporation of CO32− into PO43− sites occurred specifically for the P-deficient AgHAs. While antibacterial properties increased, osteoblast adhesion decreased with increasing Ag content for the Ca-deficient AgHAs, as anticipated. In contrast, significant antibacterial properties with good osteoblast behavior were observed on the P-deficient AgHAs even with a lower Ag content, owing to carbonated HA. Thus, this showed that by synthesizing AgHA using P-deficient precursors with carbonate substitution, one can keep the antibacterial properties of Ag in HA while reducing its toxic effect on osteoblasts.

  15. Unique crystallographic texture formation in Inconel 718 by laser powder bed fusion and its effect on mechanical anisotropy Peer-reviewed

    O. Gokcekaya, T. Ishimoto, S. Hibino, J. Yasutomi, T. Narushima, T. Nakano

    Acta Mater. 212 116876 2021/04

    DOI: 10.1016/j.actamat.2021.116876  

    ISSN:1359-6454

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    Additive manufacturing offers an exclusive way of anisotropic microstructure control with a high degree of freedom regarding variation in process parameters. This study demonstrates a unique texture formation in Inconel 718 (IN718) using a bidirectional laser scan in a laser powder bed fusion (LPBF) process for tailoring the mechanical properties. We developed three distinctive textures in IN718 using LPBF: a single-crystal-like microstructure (SCM) with a <110> orientation in the build direction (BD), crystallographic lamellar microstructure (CLM) with a <110>-oriented main layer and <100>-oriented sub-layer in the BD, and polycrystalline with a weak orientation. The microstructure observations and finite element simulations showed that the texture evolution of the SCM and CLM was dominated by the melt-pool shape and related heat-flow direction. The specimen with CLM exhibited a simultaneous improvement in strength and ductility owing to the stress-transfer coefficient between the <110>-oriented main and <100>-oriented sub-grains, showing superior mechanical properties compared to cast-IN718. This behavior is largely attributed to the presence of the boundary between the main and sub-layers (crystallographic grain boundary) lying parallel to the BD uniquely formed under the LPBF process. Furthermore, the strength–ductility balance of the part with the CLM can be controlled by changing the stress-transfer coefficient and the Schmidt factor through an alteration of the loading axis. Control of the crystallographic texture, including the CLM formation, is beneficial for tailoring and improving the mechanical performance of the structural materials, which can be a promising methodology.

  16. Improvement of mechanical properties relating to microstructure for biomedical Co–Cr–W–Ni alloys with addition of Mn and Si Peer-reviewed

    K. Ueki, S. Yanagihara, K. Ueda, M. Nakai, T. Nakano, T. Narushima

    Mater. Trans. 62 (2) 229-238 2021/02

    Publisher: Japan Institute of Metals

    DOI: 10.2320/matertrans.MT-M2020300  

    ISSN:1345-9678

    eISSN:1347-5320

  17. Improvement of Strength and Ductility by Combining Static Recrystallization and Unique Heat Treatment in Co-20Cr-15W-10Ni Alloy for Stent Application

    Kosuke Ueki, Soh Yanagihara, Kyosuke Ueda, Masaaki Nakai, Takayoshi Nakano, Takayuki Narushima

    Materials Science Forum 1016 1503-1509 2021/01

    Publisher: Trans Tech Publications, Ltd.

    DOI: 10.4028/www.scientific.net/msf.1016.1503  

    ISSN:0255-5476

    eISSN:1662-9752

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    The Co-20Cr-15W-10Ni (CCWN, mass%) alloy has excellent corrosion resistance and strength-ductility balance and is applied in almost all balloon-expandable stent platforms. To further reduce the invasiveness of stent placement, it is necessary to reduce the diameter of the stent. That is, both high strength and high ductility should be achieved while maintaining a low yield stress. In our previous studies, it was discovered that low-temperature heat-treatment (LTHT) at 873 K improves the elongation of the CCWN alloy. In this study, we focused on the grain refinement by swaging and static recrystallization to improve the strength of the alloy. The as-swaged alloy was recrystallized at 1373–1473 K for 100–300 s, followed by LTHT. A fine grain structure with an average grain size of 3–17 μm was obtained by static recrystallization. The η-phase (M<sub>12</sub>X-M<sub>6</sub>X type precipitates, M: metallic elements, X: C and/or N) formed during the recrystallization at 1373–1448 K. The alloys recrystallized at 1448 and 1473 K had a homogeneous structure with a small variation in the grain size. On the other hand, the alloys recrystallized at 1373 and 1423 K had an inhomogeneous structure in which fine and coarse grains were mixed. Both the strength and ductility of the CCWN alloy were improved by combining high-temperature short-time recrystallization and LTHT.

  18. Effect of scan length on densification and crystallographic texture formation of pure chromium fabricated by laser powder bed fusion Peer-reviewed

    O. Gokcekaya, T. Ishimoto, T. Todo, R. Suganuma, R. Fukushima, T. Narushima, T. Nakano

    Crystals 11 (1) 9-14 2021/01

    DOI: 10.3390/cryst11010009  

    eISSN:2073-4352

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    Processing of pure chromium (Cr) encounters substantial challenges due to its high melting point and intrinsic brittleness. Although laser powder bed fusion processing (LPBF) offers a novel processing approach by reaching the temperature required to melt pure Cr, the high ductile-to-brittle transformation temperature (DBTT) of pure Cr prevents the density of the as-built Cr component from reaching the level of industrial acceptance. This study focuses on raising the quality of the as-built pure Cr components to the industrial level while considering the effect of scan length on densification and crystallographic texture. It was found that short scan length induced by feature size improved the density of as-built specimens while strengthening the texture suggesting uniform heat distribution and lower thermal gradients as a result of short time intervals in scanning tracks and layers. It was discovered that cracking caused by residual stress was detrimental to densification due to the DBTT characteristic of pure Cr, which was localized at high-angle grain boundaries (HAGBs) with high misorientation. The decrease in density and misorientation of HAGBs owing to the increase in grain size and texture strength, respectively, improved the density of as-built Cr up to 97.6% and altered its mechanical properties. Therefore, these findings offer new insight into the LPBF processing of metals with high DBTT characteristics.

  19. Formation of carbon-added anatase-rich TiO2 layers on titanium and their antibacterial properties in visible light International-journal Peer-reviewed

    Takatoshi Ueda, Naoki Sato, Ryusuke Koizumi, Kyosuke Ueda, Koyu Ito, Kouetsu Ogasawara, Takayuki Narushima

    Dental Materials 37 (2) e37-e46 2021/01

    Publisher: Elsevier BV

    DOI: 10.1016/j.dental.2020.10.009  

    ISSN:0109-5641

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    OBJECTIVE: To avoid risk of infections associated with dental implants, thermal oxidation processes for practical dental Ti alloys were studied for both high bonding strength and antibacterial properties in visible light. METHODS: Two-step thermal oxidation, comprising carburization (first step of treatment: in Ar-1%CO gas) and subsequent oxidation (second step of treatment: in air), was conducted on commercially pure (CP) Ti, Ti-6Al-4V (Ti64), and Ti-6Al-7Nb (Ti67) alloys to form TiO2 layers. Their bonding strengths and antibacterial properties against Escherichia coli (E. coli) in visible light (λ ≥ 400 nm) were evaluated. RESULTS: TiO2 layers formed on each metal were composed of anatase and/or rutile. Anatase fraction and carbon concentration in the layers decreased with increasing temperature in the second step of treatment. Antibacterial properties of the TiO2 layers were dependent on the temperature in the second step of treatment. An approximate antibacterial activity value of 2 (killing ∼99% bacteria) was obtained when the temperatures in the second step of treatment were 673 and 773 K for CP Ti, 773 K for Ti64, and 773 and 873 K for Ti67. It was found that the TiO2 layer must contain carbon and be anatase-rich to exhibit excellent antibacterial properties. Bonding strength between the substrate and TiO2 layers formed at 773 K in the second step of treatment exceeded 80 MPa and was independent of substrate type. SIGNIFICANCE: TiO2 layers, possessing both high bonding strength and excellent antibacterial properties, were successfully formed on practical dental Ti alloys via two-step thermal oxidation.

  20. Crystallographic orientation control of pure chromium via laser powder-bed fusion and improved high temperature oxidation resistance Peer-reviewed

    O. Gokcekaya, N. Hayashi, T. Ishimoto, K. Ueda, T. Narushima, T. Nakano

    Additive Manufacturing 36 101624-101624 2020/10

    Publisher: Elsevier BV

    DOI: 10.1016/j.addma.2020.101624  

    ISSN:2214-8604

  21. Development of α+β-type biomedical Ti-Nb alloys with high oxygen content Peer-reviewed

    K. Ueda, M. Omiya, Y. Hirose, T. Narushima

    MATEC Web of Conferences 321 05003-05003 2020/10

    Publisher: EDP Sciences

    DOI: 10.1051/matecconf/202032105003  

    eISSN:2261-236X

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    Ti-(5–20)Nb-(0.5–1)O alloys (mass%) were investigated for developing low-cost biomedical α+β-type Ti alloy. Ti-(5, 10, 15, 20)Nb-(0.5, 0.75, 1)O alloys (mass%) were arc-melted and forged into bars. The forged alloy bars were heat-treated at 873 to 1373 K for 3.6 ks in an Ar atmosphere and quenched in iced water. β transus (<italic>T</italic><sub>β</sub>) of the Ti-Nb-O alloys decreased with increasing Nb content. An increase in the oxygen content led to an increase in <italic>T</italic><sub>β</sub>. After quenching, the formation of α′ martensite was observed in Ti-5Nb-<italic>y</italic>O alloys. An increase in the Nb content to 10 mass% led to the formation of α′ and α″ martensites. A further increase in the Nb content to 15 and 20mass% resulted in the formation of more α″ martensites. The boundary temperature for the formation of α′ and α″ martensite in the Ti-10Nb-<italic>y</italic>O alloys increased with increasing oxygen content, because oxygen enhances the Nb distribution to the β phase. The ultimate tensile strength of the Ti-<italic>x</italic>Nb-0.75O alloys heattreated to obtain the α-phase fraction (<italic>f</italic><sub>α</sub>) of 0.5 was over 1000 MPa, except for the Ti-15Nb-0.75O alloy. The total elongation decreased with increasing Nb content. The Ti-5Nb-0.75O alloy exhibited excellent strength-ductility balance as a low-cost α+β-type biomedical Ti alloy.

  22. Fabrication and bioresorbability of Ag- and Ta-containing amorphous calcium phosphate films formed on titanium substrates by RF magnetron sputtering Peer-reviewed

    J. Wu, K. Ueda, T. Narushima

    MATEC Web of Conferences 321 05007-05007 2020/10

    Publisher: EDP Sciences

    DOI: 10.1051/matecconf/202032105007  

    eISSN:2261-236X

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    Silver (Ag)- and tantalum (Ta)-containing amorphous calcium phosphate (ACP) coating films were fabricated on titanium substrates by radiofrequency magnetron sputtering for biomedical applications. The sputtering targets were hot-pressed into 10 mol% Ag-containing ß-tricalcium phosphate sintered compacts with and without 8 mol% Ta. The fabricated ACP coating films were dense and smooth, with all elements distributed homogeneously along the depth direction. In addition, Ag existed as ions in the ACP regardless of the presence of Ta. The resorbability of the Ag-containing ACP coating films in simulated body fluids was suppressed by the addition of Ta. The concentration of detected Ag ions was higher in diluted nutrient broth solution than in Tris-HCl solution.

  23. Predicting the parabolic rate constants of high-temperature oxidation of Ti alloys using machine learning Peer-reviewed

    S.Kr. Bhattacharya, R. Sahara, T. Narushima

    Oxid. Met. 94 205-218 2020/06

    DOI: 10.1007/s11085-020-09986-3  

  24. Fabrication of Ag and Ta co-doped amorphous calcium phosphate coating films by radiofrequency magnetron sputtering and their antibacterial activity Peer-reviewed

    Jun Wu, Kyosuke Ueda, Takayuki Narushima

    Materials Science and Engineering: C 109 110599-110599 2020/04

    Publisher: Elsevier BV

    DOI: 10.1016/j.msec.2019.110599  

    ISSN:0928-4931

  25. Using HAADF-STEM for atomic-scale evaluation of incorporation of antibacterial Ag atoms in a β-tricalcium phosphate structure Peer-reviewed

    Ozkan Gokcekaya, Kyosuke Ueda, Takayuki Narushima, Takayoshi Nakano

    Nanoscale 12 (31) 16596-16604 2020

    Publisher: Royal Society of Chemistry (RSC)

    DOI: 10.1039/d0nr04208k  

    ISSN:2040-3364

    eISSN:2040-3372

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    <p>HAADF-STEM technique is introduced to locate the incorporated antibacterial Ag atoms in beam-sensitive β-TCP structure.</p>

  26. Precipitation during γ-ε phase transformation in biomedical co-cr-mo alloys fabricated by electron beam melting Peer-reviewed

    Kosuke Ueki, Motoka Kasamatsu, Kyosuke Ueda, Yuichiro Koizumi, Daixiu Wei, Akihiko Chiba, Takayuki Narushima

    Metals 10 (1) 71-1-13 2020/01

    DOI: 10.3390/met10010071  

    eISSN:2075-4701

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    © 2020 by the authors. Licensee MDPI, Basel, Switzerland. We studied the precipitates that were induced during γ-ε phase transformation in biomedical Co-28Cr-6Mo (mass%) alloys that were fabricated by electron beam melting with carbon contents of 0.184 and 0.018 mass%. In the high-C as-built alloy, M23X6-type, π-phase (M3T2X-type), and η-phase (M6X-M12X-type) precipitates were observed (M and T: metallic elements, X: C and/or N). σ-phase (Co(Cr,Mo)), π-phase, and Co3Mo2Si-type precipitates were observed in the low-C as-built alloy. This is the first report that shows the presence and chemical composition of this precipitate, as the Co3Mo2Si-type precipitate has not been detected in biomedical Co-Cr-Mo alloys before. After aging in the ε-phase stability region, the high-C and low-C alloys both contained a single ε-phase matrix, and the amount of π-phase precipitates increased. Conversely, the amount of π-phase precipitates in both alloys decreased when a reverse transformation treatment was applied in the γ-phase stability region after aging. In the low-C alloy, the amount of Co3Mo2Si-type precipitates increased after reverse transformation treatment. These results indicate that the dissolution of π-phase precipitates and the formation of Co3Mo2Si-type precipitates during reverse transformation promote the formation of fine γ-phase grains at the precipitate/ε-phase matrix interface, because the formation and dissolution of these precipitates affect the γ-phase stability of the matrix.

  27. Overcoming the strength-ductility trade-off by the combination of static recrystallization and low-temperature heat treatment in Co-Cr-W-Ni alloy for stent application Peer-reviewed

    K. Ueki, S. Yanagihara, K. Ueda, M. Nakai, T. Nakano, T. Narushima

    Mat. Sci. Eng. A 766 2019/09

    Publisher: ELSEVIER SCIENCE SA

    DOI: 10.1016/j.msea.2019.138400  

    ISSN:0921-5093

    eISSN:1873-4936

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    A process combining swaging, static recrystallization, and heat treatment at 873 K (low-temperature heat-treatment, LTHT) was developed for achieving both high ultimate strength and high ductility in Co-20Cr-15W-10Ni (mass%, CCWN) alloy for stent application. The alloys swaged to a sectional area reduction rate of 58.3% were annealed at 1373-1473 K for 30-300 s. Under annealing at 1373 K for 300 s, a fine grain structure with an average grain size of similar to 6 mu m formed, while under annealing at 1473 K, a structure with an average grain size of 12 mu m formed after 120 s. In the alloys annealed at 1373-1448 K, the formation of eta-phase precipitates (M6X-M12X type, M: metallic elements, X: C and/or N) was observed, while no precipitates were observed in the alloys annealed at 1473 K. The improvement in ultimate strength by grain refinement was confirmed. Alloys annealed at 1473 K showed higher ductility compared to those annealed at 1373-1448 K even if the grain size was similar. It is considered that the eta-phase precipitates deteriorated the ductility of the annealed alloys. LTHT suppressed the strain-induced martensitic gamma-to-epsilon transformation to improve the ductility of the fine-grained as well as coarse-grained alloys. Thus, regardless of the grain size, it is newly evidenced that LTHT effectively improves ductility in CCWN alloy. By combining high-temperature short-time annealing and LTHT, both the ultimate strength and ductility of Co-2OCr-15W-10Ni (mass%) alloy improved, and it was possible to provide properties suitable for next-generation balloon-expandable stents with Co-20Cr-15W-10Ni (mass%) alloy.

  28. Effect of nonmetallic inclusions on fatigue properties of superelastic Ti-Ni fine wire Peer-reviewed

    F. Yamashita, Y. Ide, S. Kato, K. Ueda, T. Narushima, S. Kise, K. Ishikawa, M. Nishida

    Metals 9 (9) 999 2019/09

    DOI: 10.3390/met9090999  

    eISSN:2075-4701

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    This study investigated the effects of the types and length of nonmetallic inclusions on fatigue properties in rotating bending fatigue testing of Ti-Ni alloy fine wire. It was fabricated to include titanium carbides Ti(C,O) and titanium oxides Ti4 Ni2 Ox as either single phases or a mixture of both phases as nonmetallic inclusions in Ti-Ni alloy. The fatigue strength of Ti-Ni alloy depended on the number of nonmetallic inclusions of a length of ≥2 µm. Compared with Ti(C,O), Ti4 Ni2 Ox is coarse. It also exhibited a trend of readily forming particles and void assemblies, which are a defect morphology that originates from nonmetallic inclusions and readily act as crack origins of fatigue fractures.

  29. Formation of photocatalytic active TiO2 layers on Ti-Nb alloys by two-step thermal oxidation Peer-reviewed

    S. Sado, T. Ueda, Y. Tokuda, N. Sato, K. Ueda, T. Narushima

    Mater. Trans. 60 (9) 1814-1820 2019/09

    DOI: 10.2320/matertrans.ME201901  

  30. COX-2 Induces T cell accumulation and IFN-γ production during the development of chromium allergy Peer-reviewed

    R. Sitalaksmi, K. Ito, K. Ogasawara, Y. Suto, M. Itabashi, K. Ueda, N. Hirasawa, T. Narushima, S. Higuchi, N. Sato, N. Hendrijantini, U. Kresnoadi, K. Sasaki

    Autoimmunity 52 (5-6) 228-234 2019/08

    DOI: 10.1080/08916934.2019.1662404  

    ISSN:0891-6934

    eISSN:1607-842X

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    Chromium (Cr) is commonly added into various metal alloys to improve some mechanical properties such as corrosion resistance, strength, and workability. However, Cr is also known to be a metal allergen for some individuals. Metal allergy is a T cell-mediated disease with symptoms of inflammation and swelling that involve inflammatory cytokines and prostaglandins. Hence, suppressing these inflammation paths by using COX-2 inhibitor might be useful in treating Cr allergy. In this study, mice were used with Cr-induced allergy challenge model. The mice were injected with celecoxib once per day for 7 days one hour after the challenge. Footpad samples were stained with haematoxylin and eosin (H&E), and lymphocytes were isolated from popliteal lymph nodes for the flow cytometric analysis. The results show that both prostaglandin E2 (PGE2), a known mediator of inflammation, and cyclooxygenases (COX)-2 have important roles in the development of Cr allergy. Further, COX-2 inhibitor, celecoxib, was effective in relieving swelling and inflammation in Cr-allergic mice concordant with suppression of IFN-γ production by CD8+ T cells and T cell accumulation in the lymph nodes. Therefore, the inhibition of COX-2 may be a therapeutic target for Cr allergy, and additional molecules in the PGE2 signalling pathway may also be an effective therapeutic target for the treatment of metal allergy.

  31. Deoxidation of Ti melt by newly developed two-step plasma arc melting process using hydrogen Peer-reviewed

    M. Watanabe, F. Sato, R. Abe, K. Ueda, D. Matsuwaka, F. Kudo, T. Narushima

    Metall. Mater. Trans. B 50 (4) 1553-1558 2019/08

    DOI: 10.1007/s11663-019-01608-x  

  32. Visible-light-responsive antibacterial activity of Au-incorporated TiO2 layers formed on Ti-(0-10)at%Au alloys by air oxidation. International-journal Peer-reviewed

    Takatoshi Ueda, Kyosuke Ueda, Koyu Ito, Kouetsu Ogasawara, Hiroyasu Kanetaka, Takayuki Mokudai, Yoshimi Niwano, Takayuki Narushima

    Journal of biomedical materials research. Part A 107 (5) 991-1000 2019/05

    DOI: 10.1002/jbm.a.36624  

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    Rutile TiO2 layers were formed on substrates of Ti-(0-10)at%Au alloys by a simple process of air oxidation, and their antibacterial activities were evaluated under visible-light irradiation (λ ≥ 400 nm). Au was introduced into the TiO2 layers on Ti-(1-10)at%Au alloys and existed as both metallic Au nanoparticles and dissolved Au3+ ions. The TiO2 layers that formed on Ti-5at%Au and Ti-10at%Au alloys exhibited visible-light photocatalytic activity, that is, degradation of stearic acid and antibacterial activity against Escherichia coli. These visible-light activities were attributed to the surface plasmon resonance of metallic Au nanoparticles and the decrease in bandgap energy caused by dissolved Au3+ ions. The formation of hydroxyl radicals observed under visible-light irradiation is attributable to antibacterial activity. From a cost perspective, a Ti-5at%Au alloy is more suitable as a substrate for the formation of a TiO2 layer with antibacterial properties than a Ti-10at%Au alloy. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 991-1000, 2019.

  33. Antibacterial activity of Ag nanoparticle-containing hydroxyapatite powders in simulated body fluids with Cl ions Peer-reviewed

    O. Gokcekaya, K. Ueda, K. Ogasawara, T. Narushima

    Mater. Chem. Phys. 223 473-478 2019/01

    DOI: 10.1016/j.matchemphys  

  34. Experimental and theoretical study of the effect of Si on the oxidative behavior of Ti-6Al-4V alloys Peer-reviewed

    Kodai Maeda, Satoshi Suzuki, Kyosuke Ueda, Tomonori Kitashima, Somesh Kr. Bhattacharya, Ryoji Sahara, Takayuki Narushima

    J. Alloys Compd. 776 519-528 2019/01

    DOI: 10.1016/j.jallcom.2018.10.291  

    ISSN:0925-8388

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    This paper reports the first study of the oxidative behavior of Si-containing Ti-6Al-4V alloys in air. The alloys were studied in the temperature range 910–1210 K for a maximum period of 518.4 ks, and their tensile properties at room temperature are reported. The addition of Si decreased the total mass gain during oxidation and enlarged the region in which the mass gain obeyed the parabolic rate law. The oxide scale mainly consisted of rutile and α-Al2O3 phases. The results of the XPS analysis suggest that in rutile, Si exists as both Si4+ ions and SiO2. First-principles calculations indicated that Si4+ ions stably dissolved into the interstitial sites in rutile, which suppresses oxygen migration through rutile by decreasing the number of oxygen vacancies, thereby inhibiting oxide scale formation. The reaction layer consisting of Ti3Al and α″ phases on Ti-1mass% Si alloy suppressed the dissolution of oxygen into the substrate, i.e., α-case formation. The ratio of mass gain in α-case formation to total mass gain during oxidation at 1010 K and 1110 K ranged from 0.077 to 0.42. The addition of Si to the Ti-6Al-4V alloy was effective in improving both its oxidative resistance and tensile strength.

  35. Synchronous improvement in strength and ductility of biomedical Co–Cr–Mo alloy by unique low-temperature heat treatment Peer-reviewed

    K. Ueki, M. Abe, K. Ueda, M. Nakai, T. Nakano, T. Narushima

    Mat. Sci. Eng. A 739 53-61 2019/01

    Publisher: ELSEVIER SCIENCE SA

    DOI: 10.1016/j.msea.2018.10.016  

    ISSN:0921-5093

    eISSN:1873-4936

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    The microstructure and tensile properties of Co-27Cr-6Mo (mass%) alloys heat-treated at 673-1373 K were studied. Lower elongation was observed after heat treatment at 1073 K due to formation of carbonitride precipitates. In contrast, when low-temperature heat treatment (LTHT) was applied at 673-873 K, both the ultimate tensile strength and elongation synchronously improved compared with the solution-treated alloy. Electron backscatter diffraction analysis for plastic-strained alloys and in situ X-ray diffraction analysis under stress induced conditions revealed that the strain-induced martensitic transformation (SIMT) of the gamma(fcc)-phase to epsilon(hcp)-phase during plastic deformation was suppressed by the LTHT. Stacking faults (thin epsilon-phase) were observed to collide in the LTHT alloys. The following mechanisms for the synchronous improvement in the tensile strength and elongation after LHTH are proposed. First, stacking faults with multiple variants were formed during LTHT. Then, the epsilon-phase of a single variant formed by SIMT during plastic deformation collides with preexisting multi-variant stacking faults formed during LTHT, increasing the tensile strength. In addition, the SIMT during plastic deformation is suppressed in the high-plastic-strain region by the collision. This decreases the total amount of epsilon-phase formed during plastic deformation, which improves the ductility. We demonstrated that LTHT of Co-Cr-Mo alloys effectively improves the performance and mechanical safety of spinal fixation implants, which often fracture because of fatigue cracking.

  36. Mechanism of oxidation of pure and Si-segregated α-Ti surfaces Peer-reviewed

    S. K. Bhattacharya, R. Sahara, S. Suzuki, K. Ueda, T. Narushima

    463 686-692 2019/01

    DOI: 10.1016/j.apsusc.2018.08.253  

  37. Heterogeneous microstructures and corrosion resistance of biomedical Co-Cr-Mo alloy fabricated by electron beam melting (EBM) Peer-reviewed

    Daixiu Wei, Yuichiro Koizumi, Akihiko Chiba, Kosuke Ueki, Kyosuke Ueda, Takayuki Narushima, Yusuke Tsutsumi, Takao Hanawa

    Additive Manufacturing 24 103-114 2018/12

    DOI: 10.1016/j.addma.2018.09.006  

    eISSN:2214-8604

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    © 2018 We have investigated the spatial distribution of microstructures of a Co-Cr-Mo alloy rod fabricated by Electron Beam Melting (EBM) method along built height. The topside of the rod is rich in γ-fcc phase and consists of fine grains with high local distortion density. The bottom part has an ε-hcp single phase and consists of relatively coarser grains with low local distortion density. The middle part of the rod consisted of the mixture of both phases. The mean grain size increases from 56 μm (at the top of the rod) to 159 μm (at the bottom), and is accompanied by a decrease in the γ-fcc phase fraction. On the other hand, a large number of precipitates including the main M 23 X 6 phase and minor phases (η-phase and π-phase) were observed. The area fraction of the precipitates increases gradually from 5.26% (at the top) to 8.73% (at the bottom), and the relative proportion of each phase fluctuates at different positions. The hardness of the top side is lower than that of the bottom side. As a result, the hardness of the samples, as well as the area fraction of precipitates formed in the samples, increases gradually from top to bottom of the rod, while corrosion resistance is uniformly high throughout the rod almost independently of the location. The mechanism behind the formation of phase distribution is discussed in terms of thermodynamic phase stability and kinetics of phase transformation accompanying the thermal history during the post-solidification process.

  38. Microstructural Changes During Plastic Deformation and Corrosion Properties of Biomedical Co-20Cr-15W-10Ni Alloy Heat-Treated at 873 K Peer-reviewed

    Kosuke Ueki, Kyosuke Ueda, Masaaki Nakai, Takayoshi Nakano, Takayuki Narushima

    Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science 49 (6) 2393-2404 2018/06/01

    Publisher: Springer Boston

    DOI: 10.1007/s11661-018-4597-0  

    ISSN:1073-5623

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    Microstructural changes were observed during the plastic deformation of ASTM F90 Co-20Cr-15W-10Ni (mass pct) alloy heat-treated at 873 K (600 °C) for 14.4 ks, and analyzed by electron backscatter diffraction and in situ X-ray diffraction techniques. The obtained results revealed that the area fraction of the ε-phase (fε) in the as-received alloy was higher than that in the heat-treated alloy in the low-to-middle strain region (≤ 50 pct), whereas the fε of the heat-treated alloy was higher than that of the as-received alloy at the fracture point. During plastic deformation, the ε-phase was preferentially formed at the twin boundaries of the heat-treated alloy rather than at the grain boundaries. According to the transmission electron microscopy observations, the thin ε-phase layer formed due to the alloy heat treatment acted as the origin of deformation twinning, which decreased the stress concentration at the grain boundaries. The results of anodic polarization testing showed that neither the heat treatment at 873 K (600 °C) nor plastic deformation affected the alloy corrosion properties. To the best of our knowledge, this is the first study proving that the formation of a thin ε-phase layer during the low-temperature heat treatment of the studied alloy represents an effective method for the enhancement of the alloy ductility without sacrificing its strength and corrosion properties.

  39. Effect of Si on the oxidation reaction of α-Ti(0 0 0 1) surface: ab initio molecular dynamics study Peer-reviewed

    Somesh Kr. Bhattacharya, Ryoji Sahara, Kyosuke Ueda, Takayuki Narushima

    Science and Technology of Advanced Materials 18 (1) 998-1004 2017/12/31

    Publisher: Taylor and Francis Ltd.

    DOI: 10.1080/14686996.2017.1403273  

    ISSN:1878-5514 1468-6996

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    We present our ab initio molecular dynamics (MD) study of the effect of Si on the oxidation of α-Ti(0001) surfaces. We varied the Si concentration in the first layer of the surface from 0 to 25 at.% and the oxygen coverage (θ) on the surface was varied up to 1 monolayer (ML). The MD was performed at 300, 600 and 973 K. For θ = 0.5 ML, oxygen penetration into the slab was not observed after 16 ps of MD at 973 K while for θ &gt  0.5 ML, oxygen penetration into the Ti slab was observed even at 300 K. From Bader charge analysis, we confirmed the formation of the oxide layer on the surface of the Ti slab. At higher temperatures, the Si atoms diffused from the first layer to the interior of the slab, while the Ti atoms moved from second layer to the first layer. The pair correlation function shows the formation of a disordered Ti-O network during the initial stage of oxidation. Si was found to have a strong influence on the penetration of oxygen in the Ti slab at high temperatures.

  40. First principles study of oxidation of Si-segregated alpha-Ti(0001) surfaces Peer-reviewed

    Somesh Kr. Bhattacharya, Ryoji Sahara, Tomonori Kitashima, Kyosuke Ueda, Takayuki Narushima

    JAPANESE JOURNAL OF APPLIED PHYSICS 56 (12) 125701-1-125701-7 2017/12

    Publisher: IOP PUBLISHING LTD

    DOI: 10.7567/JJAP.56.125701  

    ISSN:0021-4922

    eISSN:1347-4065

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    The oxidation of the alpha-Ti(0001) surface was studied using the density functional theory. To enhance the oxidation resistance, we substituted Ti atoms with Si atoms on the Ti(0001) surface. We observed that Si prefers to segregate at the surface layer of Ti(0001) compared with other subsurface layers. The Si solubility on the Ti(0001) surface, based on the segregation energy, was found to be much larger than the corresponding bulk solubility. Si segregation was found to reduce the binding between the oxygen atom and the Ti(0001) surface and hinder the diffusion of oxygen atoms into the slab. The dissociation of the oxygen molecule on the clean and Si-segregated surfaces of Ti was found to be barrierless. Overall, the Si segregation on the Ti(0001) surface was found to hinder the dissolution of oxygen in Ti. (C) 2017 The Japan Society of Applied Physics

  41. In vitro performance of Ag-incorporated hydroxyapatite and its adhesive porous coatings deposited by electrostatic spraying Peer-reviewed

    Ozkan Gokcekaya, Thomas J. Webster, Kyosuke Ueda, Takayuki Narushima, Celaletdin Ergun

    MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS 77 556-564 2017/08

    Publisher: ELSEVIER SCIENCE BV

    DOI: 10.1016/j.msec.2017.03.233  

    ISSN:0928-4931

    eISSN:1873-0191

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    Bacterial infection of implanted materials is a significant complication that might require additional surgical operations for implant retrieval. As an antibacterial biomaterial, Ag-containing hydroxyapatite (HA) may be a solution to reduce the incidences of implant associated infections. In this study, pure, 0.2 mol% and 0.3 mol% Ag incorporated HA powders were synthesized via a precipitation method. Colloidal precursor dispersions prepared from these powders were used to deposit porous coatings onto titanium and stainless steel substrates via electrostatic spraying. The porous coating layers obtained with various deposition times and heat treatment conditions were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Scratch tests were conducted to assess the adhesion strength of the coating. Antibacterial activity of Ag-incorporated HA was tested towards Escherichia coli (E. coli) at various incubation times. Osteoblast adhesion on Ag-incorporated HA was evaluated to assess biocompatibility. Improvement in adhesion strength of the coating layer was observed after the heat treatment process due to mutual ionic diffusion at the interface. The Ag-incorporated HA killed all viable E. coli after 24 h of incubation, whereas no antibacterial activity was detected with pure HA. In addition, in vitro cell culture tests demonstrated osteoblast adhesion similar to pure HA, which indicated good cytocompatibility. In summary, results of this study provided significant promise for the future study of Agincorporated HA for numerous medical applications. (C) 2017 Elsevier B.V.All rights reserved.

  42. Effect of heat treatment and alloying elements on precipitation and surface behavior of Co-Cr-Mo alloys Peer-reviewed

    Alfirano, A. Milandia, T. Narushima

    ARPN Journal of Engineering and Applied Sciences 12 (12) 3808-3812 2017/06/15

  43. In vitro evaluation of Ag-containing calcium phosphates: Effectiveness of Ag-incorporated beta-tricalcium phosphate Peer-reviewed

    Ozkan Gokcekaya, Kyosuke Ueda, Kouetsu Ogasawara, Hiroyasu Kanetaka, Takayuki Narushima

    MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS 75 926-933 2017/06

    Publisher: ELSEVIER SCIENCE BV

    DOI: 10.1016/j.msec.2017.02.059  

    ISSN:0928-4931

    eISSN:1873-0191

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    Development of bioceramics with antibacterial activity and without cytotoxicity would be beneficial for preventing infection associated with implants. This study aimed to capitalize on the antibacterial properties of silver (Ag) incorporated in or coexisting in metallic form with calcium phosphates (CaPs). The in vitro dissolution behavior, antibacterial activity, and cytotoxicity of Ag-containing CaPs with different phase fractions of hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP) were evaluated. The antibacterial activity of Ag-containing CaPs depended on the main phase of CaP), the chemical state of Ag, and the amount of incorporated Ag. Superior antibacterial activity was obtained from sustained release of Ag ions through continuous dissolution of Ag-incorporated beta-TCP compared to that obtained for HA coexisting with metallic Ag particles. Ag-containing CaPs did not exhibit any toxic effect on V79 fibroblasts. Thus, these results demonstrated the effectiveness of Ag-incorporated beta-TCP in preventing infection, with respect to long-term applications. (C) 2017 Elsevier B.V. All rights reserved.

  44. TRAV7-2*02 Expressing CD8⁺ T Cells Are Responsible for Palladium Allergy. International-journal Peer-reviewed

    Yuri Takeda, Yoshiko Suto, Koyu Ito, Wataru Hashimoto, Tadashi Nishiya, Kyosuke Ueda, Takayuki Narushima, Tetsu Takahashi, Kouetsu Ogasawara

    International journal of molecular sciences 18 (6) 1162-1-1162-12 2017/05/31

    DOI: 10.3390/ijms18061162  

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    While metallic biomaterials have led to an improvement in the quality of life, metal allergies, especially to palladium (Pd), has caused a recent increase in allergic patients. Metal allergy is known to be a T cell-mediated delayed-type hypersensitivity (DTH); however, the pathogenic T cell subsets and the specific T cell receptor (TCR) have not been identified. Therefore, we attempted to identify the pathogenic T cells responsible for Pd allergy. We found that activating CD8⁺ T cells significantly increased and that the TRAV (TCRα variable) 7-2*02 chain skewed in Pd allergic mice. Furthermore, adoptive transfer experiments revealed that in vitro-cultured Pd-stimulated antigen presenting cells (APCs) function as memory APCs with recipient mice developing Pd allergy and that the frequency of TRAV7-2*02 increases the same as conventional Pd allergic mice. In contrast, neither proliferation of CD8⁺ T cells nor increasing of TRAV7-2*02 was observed in major histocompatibility complex I (MHC I)-deficient Pd-APCs transferred to mice. Taken together, we revealed that TRAV7-2*02-expressing CD8⁺ T cells are the pathogenic T cells for the development of Pd allergy. We also identified the CDR3 consensus motif of pathogenic TCRs as CAAXSGSWQLIF in TRAV7-2*02/TRAJ (TCRα junction)22*01 positive cells. These results suggest that the specific TCRs represent novel targets for the development of diagnostics and treatments for metal allergy.

  45. Ceramic coating of Ti and its alloys using dry processes for biomedical applications Peer-reviewed

    T. Ueda, N. Kondo, S. Sado, O. Gokcekaya, K. Ueda, K. Ogasawara, T. Narushima

    Interface Oral Health Science 2016, Innovative Research on Biosis-Abiosis Intelligent Interface 23-34 2017/01/08

    DOI: 10.1007/978-981-10-1560-1_2  

  46. Development and performance of low-cost beta-type Ti-based alloys for biomedical applications using Mn additions Peer-reviewed

    P.F. Santos, M. Niinomi, H. Liu, M. Nakai, K. Cho, T. Narushima, K. Ueda, N. Ohtsu, M. Hirano, Y. Itoh

    Interface Oral Health Science 2016, Innovative Research on Biosis-Abiosis Intelligent Interface 229-245 2017/01/08

    DOI: 10.1007/978-981-10-1560-1_19  

  47. In vitro properties of Ag-containing calcium phosphates Peer-reviewed

    Ozkan Gokcekaya, Kyosuke Ueda, Takayuki Narushima, Kouetsu Ogasawara, Hiroyasu Kanetaka

    Ceramic Engineering and Science Proceedings 37 (4) 87-93 2017

    Publisher: American Ceramic Society

    DOI: 10.1002/9781119321682.ch10  

    ISSN:0196-6219

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    Infections caused by implants used for bone replacement often lead to revision surgery and delayed recovery. The use of implant materials that exhibit antibacterial activity is an effective method for decreasing the rate of such infections. Ag is widely used for fabricating implants because of its antibacterial properties. In this study, calcium phosphate powders with various Ag contents were synthesized by a precipitation method and sintered at 1373 K in air for 24 h to form compacts of biphasic hydroxyapatite (HA)/tricalcium phosphate (β-TCP) or single phase β-TCP. The in vitro dissolution test of sintered compacts was conducted in Tris-HCl solution (Tris-hydroxymethyl-aminomethane). An Escherichia coli suspension was used for the antibacterial tests. Cytotoxicity of sintered compacts toward V79 fibroblasts was evaluated. During the in vitro dissolution test of Ag-containing calcium phosphate sintered compacts, the amount of Ag ions in Tri-HCl solution initially increased and then decreased because of AgCl precipitation. The antibacterial activity of Ag-incorporated single β-TCP was clearly observed, and higher than that of the biphasic HA/β-TCP. No cytotoxicity toward V79 fibroblasts was detected for Ag-incorporated β-TCP sintered compacts.

  48. Effects of Mo Addition on the Mechanical Properties and Microstructures of Ti-Mn Alloys Fabricated by Metal Injection Molding for Biomedical Applications Peer-reviewed

    Pedro Fernandes Santos, Mitsuo Niinomi, Ken Cho, Huihong Liu, Masaaki Nakai, Takayuki Narushima, Kyosuke Ueda, Yoshinori Itoh

    MATERIALS TRANSACTIONS 58 (2) 271-279 2017

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.M2016286  

    ISSN:1345-9678

    eISSN:1347-5320

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    Ti-Mn alloys fabricated by metal injection molding (MIM) show promising performance for biomedical applications, but their low ductility (caused by high O content and the presence of pores and carbides) requires improvement. Previously, the addition of Mo to cold crucible levitation melted (CCLM) Ti-Mn alloys efficiently improved the ductility of those alloys by promoting mechanical twinning. In the present study, Mo was added to Ti-Mn alloys fabricated by MIM. Unlike fabrication by CCLM, fabrication by MIM can produce alloys with a smaller grain size, and also introduce microstructures such as pores and Ti carbides. Thus, in order to investigate how Mo addition interacts with these typical MIM features, four alloys for biomedical applications were fabricated by MIM: Ti-5Mn-3Mo (TMM-53), Ti-5Mn-4Mo (TMM-54), Ti-6Mn-3Mo (TMM-63), and Ti-6Mn-4Mo (TMM-64). Their microstructures, mechanical properties, and tensile deformation mechanisms were evaluated. Their hardness values range from 312-359 HV, and their Young s modulus values range from 84-88 GPa; both the Vickers hardness and Young s modulus show little variation among the alloys. Although the alloys show fracture features associated with a predominantly ductile fracture mode and Mo addition successfully promotes mechanical twinning in TMM-54, the elongation of these alloys is still critically low. Compared to the TMM alloys fabricated by CCLM, the TMM alloys fabricated by MIM show slightly lower hardness and Young s modulus, and comparable tensile strength, with their low elongation remaining inadequate for such applications. In particular, TMM-63 shows the best combination of mechanical properties among the present alloys, with an elongation of 4% and an ultimate tensile strength of 1145 MPa.

  49. Preparation of orthophosphate glasses in the MgO-CaO-SiO2-Nb2O5-P2O5 system Peer-reviewed

    Sungho Lee, Kyosuke Ueda, Takayuki Narushima, Takayoshi Nakano, Toshihiro Kasuga

    BIO-MEDICAL MATERIALS AND ENGINEERING 28 (1) 23-30 2017

    Publisher: IOS PRESS

    DOI: 10.3233/BME-171652  

    ISSN:0959-2989

    eISSN:1878-3619

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    BACKGROUND: Niobia/magnesia-containing orthophosphate invert glasses were successfully prepared in our earlier work. Orthophosphate groups in the glasses were cross-linked by tetrahedral niobia (NbO4) and magnesia. OBJECTIVE: The aim of this work is to prepare calcium orthophosphate invert glasses containing magnesia and niobia, incorporating silica, and to evaluate their structures and releasing behaviors. METHOD: The glasses were prepared by melt-quenching, and their structures and ion-releasing behaviors were evaluated. RESULTS: P-31 solid-state nuclear magnetic resonance (NMR) and Raman spectroscopies showed the glasses consist of orthophosphate (PO4), orthosilicate (SiO4), and NbO4 tetrahedra. NbO4 and MgO in the glasses act as network formers. By incorporating SiO2 into the glasses, the chemical durability of the glasses was slightly improved. The glasses reheated at 800 degrees C formed the orthophosphate crystalline phases, such as beta-Ca-3(PO4)(2), Mg-3(PO4)(2) and Mg3Ca3(PO4)(4) in the glasses. The chemical durability of the crystallized glasses was slightly improved. CONCLUSIONS: Orthosilicate groups and NbO4 in the glasses coordinated with each other to form Si-O-Nb bonds. The chemical durability of the glasses was slightly improved by addition of SiO2, since the field strength of Si is larger than that of Ca or Mg.

  50. Removal of Oxygen in Ti-Si Melts by Arc-Melting Peer-reviewed

    Masahito Watanabe, Fumiya Sato, Kyosuke Ueda, Daisuke Matsuwaka, Takayuki Narushima

    MATERIALS TRANSACTIONS 58 (4) 613-618 2017

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.M2017003  

    ISSN:1345-9678

    eISSN:1347-5320

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    Oxygen removal from Ti-Si melts (Si: 9.1-30 mass%) during arc melting was investigated. High-purity Si was added to either Ti with a high oxygen content (High O Ti, O: 1.6 mass%) or commercially pure Ti (CP Ti, O: 0.104 mass%) melted under Ar or He gasfiow conditions at atmospheric pressure. At Si additions of 23 mass% and 30 mass%, the oxygen content of the Ti-Si ingots decreased. After melting, Si and amorphous SiO2 powders were observed in the chamber, which suggested that the oxygen in the melts was removed in the form of SiO gas. The oxygen content of the Ti-Si ingots after melting varied as a function of position within the ingot; the residual oxygen content was lowest in the top section of the ingots and highest in the bottom section. Under the Ar gasfiow, the oxygen content of the High O Ti-30Si ingot decreased to 0.136 mass% and 0.609 mass% in the top and center sections of the ingot, respectively; similarly, the oxygen content of the CP Ti-30Si ingot decreased to 0.030 mass% and 0.051 mass% in the top and center sections, respectively. After melting under He gasfiow, the oxygen contents of the CP Ti-30Si ingot in the top, center, and bottom sections were 0.020 mass%, 0.021 mass%, and 0.029 mass%, respectively. Better uniformity of oxygen distribution in the ingots was achieved under the He gasfiow than under the Ar gasfiow because the melted region is extended in the depth direction by using He gas. During melting, no significant evaporation of Ti and Si occurred, which is an advantage of arc melting that operates at atmospheric pressure over electron beam melting that occurs in vacuum.

  51. Microstructure and Mechanical Properties of an alpha plus beta Type Ti-4V-0.6O Alloy Peer-reviewed

    Masahito Omiya, Kyosuke Ueda, Takayuki Narushima

    MATERIALS TRANSACTIONS 58 (9) 1250-1256 2017

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.L-M2017825  

    ISSN:1345-9678

    eISSN:1347-5320

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    This paper describes the design of a low-cost alpha+beta type Ti-4V-0.6O alloy and the investigation of its microstructure and mechanical properties, with a focus on heat treatability. The beta transus (T-beta) of the alloy was found to be 1195 K, as determined from the relationship between the heat treatment temperature and the volume fraction of the equiaxed a phase (f(a)). The formation of alpha' martensite exhibiting an acicular morphology was observed after heat treatments between 1073 and 1273 K. The O content in the equiaxed alpha and beta phases increased with increasing heat treatment temperature while the V content increased with decreasing heat treatment temperature. The alloy demonstrated a higher tensile strength and lower total elongation when heat-treated between 1073 and 1173 K as compared to the as-forged material, because of the formation of alpha' martensite. The reduced total elongation was caused by the increase in the hardness difference between the equiaxed a and beta (alpha' martensite) grains. The tensile strength and total elongation of the Ti-4V-0.6O alloy were comparable to those of the Ti-6Al-4V alloy, which marks the material as a low-cost alpha+beta type Ti alloy candidate.

  52. TiO2 layers on Ti-Au alloy formed by two-step thermal oxidation and their photocatalytic activity in visible-light Peer-reviewed

    Takatoshi Ueda, Shota Sado, Kyosuke Ueda, Takayuki Narushima

    MATERIALS LETTERS 185 290-294 2016/12

    Publisher: ELSEVIER SCIENCE BV

    DOI: 10.1016/j.matlet.2016.08.066  

    ISSN:0167-577X

    eISSN:1873-4979

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    Titania (TiO2) layers consisting of anatase and rutile phases were formed on Ti-4at%Au alloy surface, using a two-step thermal oxidation method of carburization followed by air oxidation. Au from the alloy was found in the formed TiO2 layer as metallic Au nanoparticles with diameter &lt; 10 nm and dissolved Au3+. The visible-light photocatalytic activity of the TiO2 layer was evaluated by the degradation of stearic acid coating upon irradiation. Marked degradation of stearic acid was observed through the measured decrease in the water contact angle. Possible mechanisms of the visible-light photocatalytic activity are discussed. (C) 2016 Elsevier B.V. All rights reserved.

  53. Improvement of microstructure, mechanical and corrosion properties of biomedical Ti-Mn alloys by Mo addition Peer-reviewed

    Pedro Fernandes Santos, Mitsuo Niinomi, Huihong Liu, Ken Cho, Masaaki Nakai, Adhitya Trenggono, Sebastien Champagne, Hendra Hermawan, Takayuki Narushima

    MATERIALS & DESIGN 110 (2016) 414-424 2016/11

    Publisher: ELSEVIER SCI LTD

    DOI: 10.1016/j.matdes.2016.07.115  

    ISSN:0264-1275

    eISSN:1873-4197

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    In previous studies, Ti-Mn alloys showed promising performance for biomedical applications, but their elongation required improvement. In this study, Mo was added to Ti-Mn alloys to promote mechanical twinning and improve their ductility. Four alloys for biomedical applications were designed and fabricated by cold crucible levitation melting: Ti-5Mn-3Mo (TMM-53), Ti-5Mn-4Mo (TMM-54), Ti-6Mn-3Mo (TMM-63), and Ti-6Mn-4Mo (TMM-64). The microstructure, mechanical properties, tensile deformation mechanisms, and electrochemical corrosion properties of the alloys were evaluated. Their hardness ranges from 336 to 373 HV. Their Young's modulus ranges from 89 to 100 GPa. Both hardness and Young's modulus tend to decrease with decreasing amount of athermal omega phase, which is caused by increasing alloying elements contents. Mo addition improves the elongation of TMM-53 and TMM-54 by promoting twinning. Conversely, it increases the tensile strength of TMM-63 and TMM-64. Particularly, TMM-54 shows an elongation of 34% with an ultimate tensile strength (UTS) of 935 MPa. TMM-63 shows an elongation of 14% and a UTS of 1220 MPa, associated to the formation of deformation-induced to phase. Moreover, Mo addition decreases the corrosion rate of the Ti-Mn alloys to a level comparable to that of commercially-pure Ti. (C) 2016 Elsevier Ltd. All rights reserved.

  54. Formation of porous layer with low Ni content on NiTi substrate by dealloying in metallic melts Peer-reviewed

    Kyosuke Ueda, Ryuma Hashimoto, Masahiro Hirohashi, Takeshi Wada, Hidemi Kato, Takayuki Narushima

    Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 63 (8) 766-770 2016/07/01

    Publisher: Journal of the Japan Society of Powder and Powder Metallurgy

    DOI: 10.2497/jjspm.63.766  

    ISSN:0532-8799

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    NiTi has been used in biomedical implants because of its shape memory effect and superelasticity. In this study, a dealloying process was applied to NiTi substrates to form porous surfaces with low Ni content. The NiTi substrates were immersed in Ce or Mg melts for dealloying Ni. The reaction layers were characterized by using SEM/EDX and XRD. Upon dealloying, a porous layer consisting of NiTi2 and α-Ti phases was obtained at the surface of the NiTi. The Ni content in the porous layer formed at the surface of the NiTi substrate decreased step-wise until it reached a value of 2.0 at%. The thickness of the porous layer obtained by using the Ce melt was higher than that obtained by using the Mg melt, which might be due to the high affinity of Ni with Ce. 1 mass% lactic acid solution was used as an eluent for eluting Ni ions from the reaction layers. Although the amount of Ni ions eluted from the reaction layer formed by using the Ce melt was higher than that eluted from the as-polished NiTi substrate, the amount of eluting Ni ions per unit area decreased. In the case of the reaction layer obtained by using the Mg melt, the amount of eluting Ni ions was comparable with that from the as-polished NiTi substrate.

  55. Microstructural evolution and mechanical properties of biomedical Co-Cr-Mo alloy subjected to high-pressure torsion Peer-reviewed

    Murat Isik, Mitsuo Niinomi, Ken Cho, Masaaki Nakai, Huihong Liu, Hakan Yilmazer, Zenji Horita, Shigeo Sato, Takayuki Narushima

    JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS 59 226-235 2016/06

    Publisher: ELSEVIER SCIENCE BV

    DOI: 10.1016/j.jmbbm.2015.11.015  

    ISSN:1751-6161

    eISSN:1878-0180

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    The effects of severe plastic deformation through high-pressure torsion (HPT) on the microstructure and tensile properties of a biomedical Co-Cr-Mo (CCM) alloy were investigated. The microstructure was examined as a function of torsional rotation number, N and equivalent strain, epsilon(eq) in the HPT processing. Electron backscatter diffraction analysis (EBSD) shows that a strain-induced martensitic transformation occurs by the HPT processing. Grain diameter decreases with increasing epsilon(eq), and the HPT-processed alloy (CCMHPT)for epsilon(eq)=45 exhibits an average grain diameter of 47 nm, compared to 70 mu m for the CCM alloy before HPT processing. Blurred and wavy grain boundaries with low-angle of misorientation in the CCMHPT sample for epsilon(eq) &lt;45 become better-defined grain boundaries with high-angle of misorientation after HPT processing for epsilon(eq)=45. Kernel average misorientation (KAM) maps from EBSD indicate that KAM inside grains increases with epsilon(eq) for epsilon(eq)&lt;45, and then decreases for epsilon(eq)=45. The volume fraction of the epsilon (hcp) phase in the CCMHPT samples slightly increases at epsilon(eq)=9, and decreases at epsilon(eq)=45. In addition, the strength of the CCM samples increases at epsilon(eq)=9, and then decrease at epsilon(eq)=45. The decrease in the strength is attributed to the decrease in the volume fraction of e phase, annihilation of dislocations, and decrease in strain in the CCMHPT sample processed at epsilon(eq)=45 by HPT. () 2015 Elsevier Ltd. All rights reserved.

  56. Fabrication of low-cost beta-type Ti-Mn alloys for biomedical applications by metal injection molding process and their mechanical properties Peer-reviewed

    Pedro Fernandes Santos, Mitsuo Niinomi, Huihong Liu, Ken Cho, Masaaki Nakai, Yoshinori Itoh, Takayuki Narushima, Masahiko Ikeda

    JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS 59 497-507 2016/06

    Publisher: ELSEVIER SCIENCE BV

    DOI: 10.1016/j.jmbbm.2016.02.035  

    ISSN:1751-6161

    eISSN:1878-0180

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    Titanium and its alloys are suitable for biomedical applications owing to their good mechanical properties and biocompatibility. Beta-type Ti-Mn alloys (8-17 mass% Mn) were fabricated by metal injection molding (MIM) as a potential low cost material for use in biomedical applications. The microstructures and mechanical properties of the alloys were evaluated. For up to 13 mass% Mn, the tensile strength (1162-938 MPa) and hardness (308-294 HV) of the MIM fabricated alloys are comparable to those of Ti-Mn alloys fabricated by cold crucible levitation melting. Ti-9Mn exhibits the best balance of ultimate tensile strength (1046 MPa) and elongation (4.7%) among the tested alloys, and has a Young's modulus of 89 GPa. The observed low elongation of the alloys is attributed to the combined effects of high oxygen content, with the presence of interconnected pores and titanium carbides, the formation of which is due to carbon pickup during the debinding process. The elongation and tensile strength of the alloys decrease with increasing Mn content. The Ti-Mn alloys show good compressive properties, with Ti-17Mn showing a compressive 0.2% proof stress of 1034 MPa, and a compressive strain of 50%. (C) 2016 Elsevier Ltd. All rights reserved.

  57. The antihistamine olopatadine regulates T cell activation in palladium allergy Peer-reviewed

    Naohiko Iguchi, Yuri Takeda, Naoki Sato, Kenichirou Ukichi, Akira Katakura, Kyosuke Ueda, Takayuki Narushima, Shigehito Higuchi, Kouetsu Ogasawara

    INTERNATIONAL IMMUNOPHARMACOLOGY 35 (35) 70-76 2016/06

    Publisher: ELSEVIER SCIENCE BV

    DOI: 10.1016/j.intimp.2016.03.021  

    ISSN:1567-5769

    eISSN:1878-1705

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    Because of its corrosion resistance palladium (Pd) has been widely used in many consumer products ranging from fashion accessories to dental materials. Recently, however, an increase in Pd allergy cases has been reported. Metal allergy is categorized as a Type IV allergy, which is characterized as a delayed-type hypersensitivity reaction in which T cells are known to play an important role; however, the precise mechanism of their action remains unclear. Here we defined the relationship between histamine and the Pd allergic reaction specifically with respect to T cell responses. To verify the effects of histamine on T cells, we examined whether there is a change in IFN-gamma production following stimulation of histamine or the antihistamine, olopatadine hydrochloride (OLP), in vitro. In addition, we assessed whether OLP administration affected the degree of footpad swelling or IFN-gamma production during the Pd allergy response in mice. We found that histamine stimulation increased IFN-gamma production in T cells, specifically enhancing IFN-gamma production in CD8(+) T cells compared with CD4(+) T cells. Interestingly, OLP suppressed the production of IFN-gamma in CD8(+) T cells, and this compound inhibited footpad swelling and IFN-gamma production in mice with Pd allergy. These results suggest that histamine promotes the Type IV allergic reaction and thus, the histamine 1 receptor (H1R) might be useful therapeutic target for treatment of metal allergy. (C) 2016 Elsevier B.V. All rights reserved.

  58. Microstructure and Mechanical Properties of Heat-Treated Co-20Cr-15W-10Ni Alloy for Biomedical Application Peer-reviewed

    Kosuke Ueki, Kyosuke Ueda, Takayuki Narushima

    METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE 47A (6) 2773-2782 2016/06

    Publisher: SPRINGER

    DOI: 10.1007/s11661-016-3488-5  

    ISSN:1073-5623

    eISSN:1543-1940

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    The microstructure and mechanical properties of a heat-treated biomedical ASTM F90 Co-20Cr-15W-10Ni (mass pct) alloy were investigated. The alloy was heat-treated at temperatures of 673 K to 1623 K (400 A degrees C to 1450 A degrees C) for holding times of 0.6 to 259.2 ks. The formation of M23X6-type (M: metallic element and X: C and N) and eta-phase (M6X-M12X type) precipitates was detected in the heat-treated alloys using a combination of electrolytic extraction and X-ray diffraction. The formation of precipitates deteriorated the ductility of the heat-treated alloys. On the other hand, both the tensile strength and elongation were improved by heat treatment at low temperatures of 673 K to 873 K (400 A degrees C to 600 A degrees C). In this heat-treated alloy, the density of stacking faults was higher than that of the as-received alloy, and the formation of the epsilon-phase was detected. (C) The Minerals, Metals & Materials Society and ASM International 2016

  59. Formation and evaluation of thermally-oxidized titania layers on commercially pure Ti Peer-reviewed

    T. Narushima, N. Umetsu, T. Ueda, S. Sado, K. Ueda

    Proceedings of Ti-2015: The 13th World Conference on Titanium 1717-1721 2016/05/06

    DOI: 10.1002/9781119296126.ch288  

  60. Preparation of Antibacterial ZnO-CaO-P2O5-Nb2O5 Invert Glasses Peer-reviewed

    Sungho Lee, Hirotaka Uehara, Anthony L, B. Maçon, Hirotaka Maeda, Akiko Obata, Kyosuke Ueda, Takayuki Narushima, Toshihiro Kasuga

    Materials Transactions 30 30-34 2016/04

  61. Improvement in mechanical strength of low-cost beta-type Ti-Mn alloys fabricated by metal injection molding through cold rolling Peer-reviewed

    Ken Cho, Mitsuo Niinomi, Masaaki Nakai, Huihong Liu, Pedro F. Santos, Yoshinori Itoh, Masahiko Ikeda, Mohamed Abdel-Hady Gepreel, Takayuki Narushima

    JOURNAL OF ALLOYS AND COMPOUNDS 664 272-283 2016/04

    Publisher: ELSEVIER SCIENCE SA

    DOI: 10.1016/j.jallcom.2015.12.200  

    ISSN:0925-8388

    eISSN:1873-4669

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    In order to develop new low-cost and high-strength beta-type titanium alloys, a Ti-13Mn was fabricated by metal injection molding. For improving its tensile strength, Ti-13Mn was subjected to cold-rolling at reduction ratios of 60% and 90%, respectively. The solutionized Ti-13Mn has pores and titanium carbide (Ti carbide) precipitates and consists of a beta phase and an athermal omega phase. The porosity of the alloy decreases from 6.1% to 0.01% after cold-rolling at a reduction ratio of 90%. Moreover, during cold-rolling, the Ti carbides are fragmented and a deformation-induced omega phase is formed. The ultimate tensile strength, 0.2% proof stress, Vickers hardness, and Young's modulus of Ti-13Mn increase from 888 MPa to 1852 MPa, from 827 MPa to 1823 MPa, from 279 Hv to 461 Hv, and from 96 GPa to 108 GPa, respectively, after cold-rolling at a reduction ratio of 90%. On the other hand, the elongations of both the solutionized and cold rolled Ti-13Mn are less than 2%. Although the elongation of Ti-13Mn is less than 2%, the tensile strength of the cold rolled Ti-13Mn is extremely high compared with that of existing titanium alloys. This large-improvement in the tensile strength of the cold rolled Ti-13Mn is attributed to the increase in the dislocation density, decrease in grain size, decrease in porosity, and formation of a deformation-induced omega phase. (c) 2015 Elsevier B.V. All rights reserved.

  62. Structures and dissolution behaviors of MgO-CaO-P2O5-Nb2O5 glasses Peer-reviewed

    Sungho Lee, Hirotaka Maeda, Akiko Obata, Kyosuke Ueda, Takayuki Narushima, Toshihiro Kasuga

    JOURNAL OF NON-CRYSTALLINE SOLIDS 438 18-25 2016/04

    Publisher: ELSEVIER SCIENCE BV

    DOI: 10.1016/j.jnoncrysol.2016.02.006  

    ISSN:0022-3093

    eISSN:1873-4812

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    MgO-CaO-P2O5-Nb2O5 glasses with the substitution of MgO for CaO consisting predominantly of meta-, pyro-, and orthophosphate groups were prepared using a melt-quenching method, and their structures and dissolution behaviors were investigated. Magnesium in the metaphosphate compositions was shown to act as a modifier oxide and coordinate phosphate groups. Magnesium in the pyro- and/or orthophosphate compositions was shown to act as a network former and to form P-O-Mg bonds, which crosslink short phosphate groups. The chemical durability of the metaphosphate glasses increased with increasing the substitution of MgO for CaO because magnesium exhibits a larger field strength than calcium. However, the durability of the pyro- and/or orthophosphate glasses decreased with increasing the MgO content: P-O-Mg bonds weakened the glass network structure and induced hydrolysis. (C) 2016 Elsevier B.V. All rights reserved.

  63. Structure and physicochemical properties of CaO-P2O5-Nb2O5-Na2O glasses Peer-reviewed

    Hirotaka Maeda, Sungho Lee, Tomohiro Miyajima, Akiko Obata, Kyosuke Ueda, Takayuki Narushima, Toshihiro Kasuga

    JOURNAL OF NON-CRYSTALLINE SOLIDS 432 60-64 2016/01

    Publisher: ELSEVIER SCIENCE BV

    DOI: 10.1016/j.jnoncrysol.2015.06.003  

    ISSN:0022-3093

    eISSN:1873-4812

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    Calcium phosphate glasses were prepared by adding Nb2O5 and Na2O. Spectroscopic analyses showed that the glasses included niobate groups, such as NbO4 and NbO6. The amount of NbO4 units, which was considered to be a network former, increased with the increase in Nb2O5 content, and the formation of an Nb-O-P bond appeared. The ion-releasing ability of the glasses in the Tris-buffer solution depended on their chemical composition. The process window of the glass, which was estimated from the temperature range between the glass transition and the onset of crystallization, increased with the increase of the Nb2O5 content of the glass. The excellent chemical durability and glass-forming ability of calcium phosphate glass were considered to originate from the formation of the Nb-O-P bond. (C) 2015 Elsevier B.V. All rights reserved.

  64. Microstructure and Mechanical Property of alpha plus beta Type Ti-(0 similar to 10) mass%V-(0.5 similar to 1) mass%O Alloys Peer-reviewed

    Kyosuke Ueda, Tatsuya Kobayashi, Takayuki Narushima

    JOURNAL OF THE JAPAN INSTITUTE OF METALS 80 (1) 60-65 2016

    Publisher: JAPAN INST METALS

    DOI: 10.2320/jinstmet.JB201503  

    ISSN:0021-4876

    eISSN:1880-6880

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    The microstructure and mechanical properties of the alpha+beta type Ti-V-O alloys with high oxygen content were investigated. Ti-(0 similar to 10) mass%V-(0.5, 0.75, 1.0) mass%O alloy ingots were prepared using arc melting and hot rolling at 1373 K and 1073 K. The alloys were heat-treated at temperatures varying from 923 K to 1323 K for 3.6 ks under Ar flow. The beta transus of the alloys was experimentally determined, and its value decreased with increasing V content and decreasing oxygen content in the alloy. Athermal omega was detected in the alloys with 6, 8 and 10 mass%V content and 0.5, 0.75 and 1 mass%O content after heat treatment at low temperatures in the range of 923 to 1123 K, wherein the V content in the beta phase was higher than 12 mass%. The formation of the athermal omega led to the increase in hardness and decrease in the elongation and reduction of area of the alloys. Based on the investigation results, it was suggested that the Ti-4 mass%V-(0.5 similar to 0.75) mass%O alloy had an excellent balance between strength and ductility.

  65. Grain Refinement Mechanism and Evolution of Dislocation Structure of Co-Cr-Mo Alloy Subjected to High-Pressure Torsion Peer-reviewed

    Murat Isik, Mitsuo Niinomi, Huihong Liu, Ken Cho, Masaaki Nakai, Zenji Horita, Shigeo Sato, Takayuki Narushima, Hakan Yilmazer, Makoto Nagasako

    MATERIALS TRANSACTIONS 57 (7) 1109-1118 2016

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.M2016052  

    ISSN:1345-9678

    eISSN:1347-5320

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    Ultrafine-grained materials often possess superior mechanical properties owing to their small grain size. The high-pressure torsion (IIPT) process is a severe plastic deformation method used to induce ultra-large strain and produce ultrafine grains. In this study, the grain refinement mechanisms in the Co-28Cr-6Mo (CCM) alloy, evolution of dislocation density as a result of HPT and its effects on mechanical properties were investigated. The dislocation density and subgrain diameter were also calculated by X-ray line profile analysis. The microstructure of the CCM alloy subjected to HPT processing (CCMHPT) was evaluated as a function of torsional rotation number, N and equivalent strain, epsilon(eq). Strain-induced gamma -&gt;epsilon transformation in neighboring ultrafine grains is observed in CCMHPT processed at epsilon(eq) = 2.25 and epsilon(eq) = 4.5. Low-angle crystal rotation around the [110] fcc direction occurs in different locations in the same elongated grain neighboring ultrafine grains, which suggests the formation of low-angle grain boundaries in CCMHPT processed at epsilon(eq) = 2.25 and epsilon(eq) = 4.5. Two possible grain refinement mechanisms are proposed. The maximum dislocation densities, which are 2.8 x 10(16) m(-2) in gamma phase and 3.8 x 10(16) m(-2) in epsilon phase, and maximum subgrain diameters, which are 21.2 nm in gamma phase and 36 nm in epsilon phase, are achieved in CCMHPT processed at epsilon(eq) = 9. IIPT processing causes a substantial increase in the tensile strength and hardness owing to the grain refinement and a significant increase in the volume fraction of epsilon phase and dislocation density.

  66. Optimization of Microstructure and Mechanical Properties of Co-Cr-Mo Alloys by High-Pressure Torsion and Subsequent Short Annealing Peer-reviewed

    Murat Isik, Mitsuo Niinomi, Huihong Liu, Ken Cho, Masaaki Nakai, Zenji Horita, Takayuki Narushima, Kyosuke Ueda

    MATERIALS TRANSACTIONS 57 (11) 1887-1896 2016

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.M2016112  

    ISSN:1345-9678

    eISSN:1347-5320

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    The main target of this study is to optimize the microstructure and to achieve an optimization for the mechanical properties in a biomedical Co-Cr-Mo (CCM) alloy with the nominal composition of Co-28Cr-6Mo (mass%) subjected to high-pressure torsion (HPT) and subsequent short annealing. The gamma -&gt;epsilon phase transformation and grain refinement occur in the CCM alloy subjected to HPT processing at an equivalent strain (epsilon(eq)) of 2.25 (CCMHPT). The HPT processing causes a decrease in the elongation due to the formation of an excessive amount of epsilon phase. For removal of the excessive amount of e phases, the CCMHPT was subjected to a short annealing (CCMHPTA). The effect of the short annealing temperature (1073 K, 1273 K, and 1473 K; annealing time was fixed at 0.3 ks) on CCMHPT was investigated. In addition, the effect of the length of duration for the short annealing (0.06 ks, 0.3 ks, and 0.6 ks;) for a fixed annealing temperature of 1273 K on CCMHPT was studied. CCMHPTA(1273 K) annealed for 0.3 ks shows a good optimization of mechanical properties that include high strength and large elongation owing to its ultra fine-grained microstructure, and removal of excessive e phases.

  67. Changes in Microstructure of Biomedical Co-Cr-Mo Alloys during Aging at 973 to 1373 K Peer-reviewed

    Kosuke Ueki, Yuto Kurihara, Shingo Mineta, Alfirano, Kyosuke Ueda, Shigenobu Namba, Takashi Yoneda, Takayuki Narushima

    MATERIALS TRANSACTIONS 57 (12) 2048-2053 2016

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MI201507  

    ISSN:1345-9678

    eISSN:1347-5320

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    Changes in the microstructure and hardness of biomedical Co-Cr-Mo forged alloys (Co-27Cr-6Mo-0.77Si-0.64Mn-0.17N-0.06C (mass%)) during aging were investigated with a focus on precipitation. After solution treatment at 1523 K for 1.8 ks, the alloys were subjected to aging at temperatures between 973 and 1373 K for up to 86.4 ks. eta-phase (M6X-M12X type), M23X6-type and pi-phase (A(2)T(3)X type) precipitates were detected after aging. The formation of pi-phase precipitates was detected in alloys aged between 1023 and 1123 K for holding times &gt;= 21.6 ks, with a nose temperature between 1073 and 1123 K. The presence of Tr-phase precipitates in the aged Co-Cr-Mo alloy is reported for the first time; N contained within the alloy is believed to contribute to formation of the yr-phase. The formation of a hexagonal-close-packed Co-based metallic phase (epsilon-phase) was observed between 1023 and 1123 K. The Vickers hardness increased in alloys aged at 1023 and 1073 K. This increase in hardness is attributed to the presence Of pi-phase and epsilon-phase and their wide-area precipitation.

  68. Effects of Precipitates and Albumin in Simulated Body Fluids on Pin-on-Disk Wear Behavior of Biomedical Co-Cr-Mo Alloys Peer-reviewed

    Kyosuke Ueda, Motoka Kasamatsu, Masanori Tanno, Kosuke Ueki, Jean Geringer, Takayuki Narushima

    MATERIALS TRANSACTIONS 57 (12) 2054-2059 2016

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MI201518  

    ISSN:1345-9678

    eISSN:1347-5320

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    Pin-on-disk wear tests using Co-Cr-Mo (CCM) alloy pins and disks were conducted in 0.14 NI NaCl solutions with and without albumin. To clarify the effect of precipitates in the CCM alloys on the alloy wear behavior, as-received (having precipitates) and solution-treated (having no precipitates) CCM alloys were used as specimens. Friction coefficients during wear testing were measured. After the wear testing, the mass loss of pins and disks, wear tracks on the disks, and the wear debris were examined using scanning electron microscopy (SEM) and laser microscopy (LM). The concentration of metallic ions in solution was analyzed by inductively coupled plasma-atomic emission spectroscopy (ICPAES). In the solution without albumin, the friction coefficient increased with increasing sliding time and discontinuous wear grooves with attached and detached sections were observed, indicating that adhesive wear was dominant. On the other hand, in the solution with albumin, the friction coefficient was constant independent of the sliding distance and continuous wear grooves were observed, indicating that abrasive wear was dominant. High amounts of mass loss were detected from the as-received alloys in the albumin solution, and it is theorized that the wear debris (including precipitates) enhanced the third-body wear. The concentration of Cr ions in solution was lower than the expected values based on the alloy composition. In the solution with albumin, it was thought that the Cr ions bonded with the albumin, increasing the amount of available Cr ions in solution.

  69. Preparation of Antibacterial ZnO-CaO-P2O5-Nb2O5 Invert Glasses Peer-reviewed

    Sungho Lee, Hirotaka Uehara, Anthony L. B. Macon, Hirotaka Maeda, Akiko Obata, Kyosuke Ueda, Takayuki Narushima, Toshihiro Kasuga

    MATERIALS TRANSACTIONS 57 (12) 2072-2076 2016

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MI201503  

    ISSN:1345-9678

    eISSN:1347-5320

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    ZnO-CaO-P2O5-Nb2O5 invert glasses, with ZnO substituted for CaO, were successfully prepared using a melt-quenching method. Their structures, dissolution behaviors, and antibacterial abilities were evaluated. Niobate switched its role of network former to modifier with increasing ZnO content, as Zn2+ ions preferentially coordinated with phosphate groups. In parallel, with increasing content of ZnO in the glasses, P-O-Zn bonds were formed, which crosslinked phosphate groups with ZnO acting as a network former. As a result, the glass-forming ability and chemical durability of the glasses were improved. The glasses showed antibacterial ability to gram-positive and-negative bacteria.

  70. Effect of light elements on fatigue properties of NiTi wires for designing biomedical stents Peer-reviewed

    K. Hara, K. Ueda, T. Narushima, F. Yamashita, K. Ishikawa

    Proceedings of the 24th International Symposium on Processing and Fabrication of Advanced Materials, PFAM XXIV 20-28 2015/12/18

  71. Microstructure, tensile properties and corrosive properties of ASTM F90 Co-20Cr-15W-10Ni Alloys Peer-reviewed

    K. Ueki, K. Ueda, T. Narushima

    Proceedings of the 24th International Symposium on Processing and Fabrication of Advanced Materials, PFAM XXIV 50-58 2015/12/18

  72. In vitro evaluation of Ag-containing calcium phosphates Peer-reviewed

    O. Gokcekaya, K. Ueda, T. Narushima, K. Ogasawara

    Proceedings of the 24th International Symposium on Processing and Fabrication of Advanced Materials, PFAM XXIV 95-103 2015/12/18

  73. Design, microstructural characterization and mechanical evaluation of novel Ti-Mn-Mo alloys for biomedical applications Peer-reviewed

    P.F. Santos, M. Niinomi, H. Liu, M. Nakai, K. Cho, T. Narushima

    Proceedings of the 24th International Symposium on Processing and Fabrication of Advanced Materials, PFAM XXIV 120-125 2015/12/18

  74. Behavior of oxygen in arc-melted Ti–Si alloys Peer-reviewed

    M. Watanabe, K. Ueda, T. Narushima, D. Matsuwaka

    Proceedings of the 24th International Symposium on Processing and Fabrication of Advanced Materials, PFAM XXIV 513-520 2015/12/18

  75. Microstructure and balanced mechanical properties of short-time solution treated Co-Cr-Mo alloys processed through high-pressure torsion Peer-reviewed

    M. Isik, M. Niinomi, H. Liu, M. Nakai, K. Cho, Z. Horita, T. Narushima

    Proceedings of the 24th International Symposium on Processing and Fabrication of Advanced Materials, PFAM XXIV 680-685 2015/12/18

  76. Formation of TiO2 layers on commercially pure Ti and Ti-Mo and Ti-Nb alloys by two-step thermal oxidation and their photocatalytic activity Peer-reviewed

    Shota Sado, Takatoshi Ueda, Kyosuke Ueda, Takayuki Narushima

    APPLIED SURFACE SCIENCE 357 2198-2205 2015/12

    Publisher: ELSEVIER SCIENCE BV

    DOI: 10.1016/j.apsusc.2015.09.211  

    ISSN:0169-4332

    eISSN:1873-5584

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    Anatase-containing TiO2 layers were formed on commercially pure (CP) Ti and Ti-25mass%Mo (Ti-25Mo) and Ti-25mass%Nb (Ti-25Nb) alloys by two-step thermal oxidation. The first-step treatment was conducted in an Ar-1%CO atmosphere at 1073K for 3.6 ks, and the second-step treatment was conducted in air at 673-1073 K for 10.8 ks. The second-step temperature range for anatase formation was wider in the Ti alloys than in CP Ti. Photo-induced superhydrophilicity under UV irradiation was observed for the TiO2 layers with anatase fractions &gt;= 0.6 on CP Ti and the Ti-25Mo alloy, and with anatase fractions &gt;= 0.18 on the Ti-25Nb alloy. The TiO2 layers on the Ti-25Nb alloy exhibited excellent photocatalytic activity in the low anatase fraction region, which is considered to be caused by the incorporation of 1-3 at% Nb into the TiO2 layers. The rate constant of methylene blue degradation showed maxima at anatase fractions of 0.6-0.9. (C) 2015 Elsevier B.V. All rights reserved.

  77. Visible light activities of TiO<SUB>2</SUB> layers formed on Ti-Ag and Ti-Au alloys by thermal oxidation Peer-reviewed

    T. Ueda, S. Sado, K. Ueda, T. Narushima

    Proceedings for International Symposium on Eco Topia Science 2015 2015/11

  78. Structures and dissolution behaviors of CaO-P2O5-TiO2/Nb2O5 (Ca/P &gt;= 1) invert glasses Peer-reviewed

    Sungho Lee, Hirotaka Maeda, Akiko Obata, Kyosuke Ueda, Takayuki Narushima, Toshihiro Kasuga

    JOURNAL OF NON-CRYSTALLINE SOLIDS 426 35-42 2015/10

    Publisher: ELSEVIER SCIENCE BV

    DOI: 10.1016/j.jnoncrysol.2015.06.024  

    ISSN:0022-3093

    eISSN:1873-4812

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    Common phosphate glasses for example, those in the metaphosphate region show potential as biodegradable materials. Some applications, such as biocompatible thin films coated on titanium or its alloys using radiofrequency magnetron sputtering methods, require films with good chemical durability. In the present work, CaO-P2O5-TiO2/Nb2O5 glasses with a Ca/P ratio of &gt;= 1.00 were prepared using a melt-quenching method, and their structures and dissolution behaviors were investigated. When the Ca/P ratio was increased, the amount of orthophosphate (Q(p)(0)) group in the glasses increased, and that of pyrophosphate (Q(p)(1)) group decreased. The amount of Q(p)(0) group was greater than the amount of Qp1 groups in glasses with a Ca/P ratio of &gt;= 1.14. Intermediate oxides (i.e., TiO2 and Nb2O5) in the glasses cross-linked with the phosphate groups to form P-O-Ti/Nb bonds; these bonds were expected to take a tetrahedral form. The glasses prepared in the present work showed excellent chemical durability, because of the P-O-Ti/Nb bonds and the delocalized P=O bonds that resulted from the increasing Q(p)(0) content in the glasses. (C) 2015 Elsevier B.V. All rights reserved.

  79. Microstructures, mechanical properties and cytotoxicity of low cost beta Ti-Mn alloys for biomedical applications Peer-reviewed

    Pedro Fernandes Santos, Mitsuo Niinomi, Ken Cho, Masaaki Nakai, Huihong Liu, Naofumi Ohtsu, Mitsuhiro Hirano, Masahiko Ikeda, Takayuki Narushima

    ACTA BIOMATERIALIA 26 366-376 2015/10

    Publisher: ELSEVIER SCI LTD

    DOI: 10.1016/j.actbio.2015.08.015  

    ISSN:1742-7061

    eISSN:1878-7568

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    The microstructures, mechanical properties and biocompatibility of low cost beta-type Ti-(6-18)Mn alloys were investigated after solution treatment. Ti-9Mn exhibits the best combination of tensile strength and elongation among the fabricated alloys, and its performance is comparable to or superior to those of Ti-6Al-4V ELI (Ti-64 ELI) in terms of every parameter evaluated. A hardness of 338 HV, a Young's modulus of 94 GPa, a 0.2% proof stress of 1023 MPa, an ultimate tensile strength of 1048 MPa and elongation of 19% were obtained for Ti-9Mn. Furthermore, the cell viability and metallic ion release ratios are comparable to those of commercially pure titanium, making this alloy promising for biomedical applications. The Young's modulus is also lower than that of Ti-64 ELI (110 GPa), which can possibly reduce the stress shielding effect in implanted patients. Statement of significance This study evaluates mechanical and biological performance of low cost solution treated beta-type Ti-(6, 9, 13 and 18 mass%)Mn alloys. It includes alloys containing a Mn content range higher than most previously published works (which is around or lower than 8 mass%). Furthermore, the effects of the omega phase and the beta phase stability of the alloys over some mechanical properties and microstructures are discussed. Ion release behavior under simulated body fluids and cell viability are also evaluated. For the case of the Ti-9Mn, a mechanical and biological performance that is comparable to or superior than that of the widely used Ti-6Al-4V ELI and commercially pure Ti was observed. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  80. Structure and dissolution behavior of MgO-P2O5-TiO2/Nb2O5 (Mg/P &gt;= 1) invert glasses Peer-reviewed

    Sungho Lee, Hirotaka Maeda, Akiko Obata, Kyosuke Ueda, Takayuki Narushima, Toshihiro Kasuga

    JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 123 (1442) 942-948 2015/10

    Publisher: CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI

    DOI: 10.2109/jcersj2.123.942  

    ISSN:1882-0743

    eISSN:1348-6535

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    Magnesium phosphate glasses exhibit unusual properties and were classified as 'anomalous phosphate glasses', because magnesium is attributed to a variation of the oxygen coordination number from 6 to 4. Magnesium in phosphate glasses acts as an intermediate oxide and its role was determined, relating to the phosphate chain length. In the present work, MgO-P2O5-TiO2/Nb2O5 glasses with Mg/P ratio between 1.00 and 1.36 were successfully prepared by a melt-quenching method. Magnesium in the glasses worked as a network former to form P-O-Mg bonds, which are cross-linked short phosphate chains that improved the glass-forming ability. Intermediate oxides (i.e., TiO2 and Nb2O5) in the glasses also cross-linked short phosphate chains to form P-O-Ti/Nb bonds. The chemical durability of the glasses decreased with an increase in the Mg/P ratio, because magnesium, which entered the phosphate network, weakened the glass network to induce hydrolysis. The dissolution rate of Ti4+ and Nb5+ ions showed a decreasing tendency with an increase in the Mg/P ratio. The surfaces of the glasses were considered to be covered with gel-like oxide layers containing titanium or niobium and phosphate.

  81. Formation of the chi-Phase Precipitate in Co-28Cr-6Mo Alloys with Additional Si and C Peer-reviewed

    Kei Sugawara, Alfirano, Shingo Mineta, Kyosuke Ueda, Takayuki Narushima

    METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE 46A (9) 4342-4350 2015/09

    Publisher: SPRINGER

    DOI: 10.1007/s11661-015-3008-z  

    ISSN:1073-5623

    eISSN:1543-1940

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    The precipitates of biomedical Co-28Cr-6Mo-(0.5 to 2)Si-(0.05 to 0.35)C alloys (mass pct) have been investigated before and after heat treatment, focusing on the formation of the chi-phase precipitate. The precipitates were precisely and directly analyzed after using electrolytic extraction to separate the precipitates from the alloys. Heat treatment was performed at 1523 K (1250 A degrees C) for a holding time of 0.6 ks. The chi-phase precipitate was detected with Si content of 1.3 to 2 mass pct and C content of 0.05 to 0.15 mass pct in both the as-cast and heat-treated alloys. The higher Si content and the mid-level C content of about 0.15 mass pct favored the formation of the chi-phase precipitate. Moreover, the chi-phase precipitate was not observed in the compositional range of the ASTM F 75 standard: Si content a parts per thousand currency sign1.0 mass pct and C content a parts per thousand currency sign0.35 mass pct. In the as-cast Co-28Cr-6Mo-1.3Si-0.15C alloy, which is outside of the ASTM F 75 standard, the content of the chi-phase precipitate was around 6 pct in area percent; the decrease in the ductility was detected in the tensile test of this alloy. The amount of precipitates decreased due to heat treatment at 1523 K (1250 A degrees C), where the dissolution of precipitates occurred. After the heat treatment, a single chi-phase precipitate region was detected.

  82. Synthesis and characterization of Ag-containing calcium phosphates with various Ca/P ratios Peer-reviewed

    Ozkan Gokcekaya, Kyosuke Ueda, Takayuki Narushima, Celaletdin Ergun

    MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS 53 111-119 2015/08

    Publisher: ELSEVIER SCIENCE BV

    DOI: 10.1016/j.msec.2015.04.025  

    ISSN:0928-4931

    eISSN:1873-0191

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    Ag-containing calcium phosphate (CaP) powders were synthesized by a precipitation method using aqueous solutions of calcium nitrate, silver nitrate, and ammonium phosphate. The powders were sintered at temperatures ranging from 1173 to 14731&lt;. The charged atomic ratios of (Ca + Ag)/P and Ag/(Ca + Ag) in solution were varied from 133 to 1.67 and from 0 to 030, respectively. The Ag content in the as-precipitated CaP powders increased with the charged Ag/(Ca + Ag) atomic ratio in solution and was lower than the charged Ag/(Ca + Ag) value. The as-precipitated CaP powders consisted of hydroxyapatite (HA) as the main phase. Ag nanoparticles were observed on the as-precipitated HA particles under all conditions of Ag addition. After the sintering, HA,beta-TCP (tricalcium phosphate), alpha-TCP, and beta-CPP (calcium pyrophosphate) were mainly detected as CaPs on the basis of the Ca/P atomic ratio of the as-precipitated powders. The addition of Ag stabilized the beta-TCP phase, and the distribution of Ag in beta-TCP was homogeneous. A metallic Ag phase coexisted with HA. The solubility of Ag in HA was estimated to be 0.0019-0.0061 (Ag/(Ca + Ag)) atomic ratio, which was lower than that in beta-TCP (higher than 0.0536) and higher than that of beta-CPP (below the detection limit of analyses). (C) 2015 Elsevier B.V. All rights reserved.

  83. Control of bioresorbability of amorphous calcium phosphate coating film with niobium added Peer-reviewed

    K. Ueda, T. Takahashi, A. Obata, T. Kasuga, T. Goto, T. Narushima

    Proceedings of the Biomaterials International Conference 2015 1026 2015/06

  84. Effect of heat treatment of the microstructure and mechanical properties of biomedical Co-20Cr-15W-10Ni alloy Peer-reviewed

    K. Ueki, K. Ueda, T. Narushima

    Proceedings of the Biomaterials International Conference 2015 1182 2015/06

  85. Evaluation of photocatalytic activity of the tio2 layer formed on ti by thermal oxidation Peer-reviewed

    Takayuki Narushima, Shota Sado, Natsumi Kondo, Kyosuke Ueda

    Interface Oral Health Science 2014: Innovative Research on Biosis-Abiosis Intelligent Interface 65-78 2015/01/01

    Publisher: Springer Japan

    DOI: 10.1007/978-4-431-55192-8_6  

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    Two-step thermal oxidation was proposed for Ti and Ti alloys as a surface-treatment process for preparing an anatase-containing TiO2 layer. This process consisted of treatment in a CO-containing atmosphere (first step) and subsequent treatment in air (second step). In this chapter, first, the current status of TiO2 coating onto Ti and Ti alloys for biomedical applications is reviewed then our recent work on the phase and microstructure of TiO2 layers prepared on commercially pure (CP) Ti, Ti-25mass%Mo alloy, and Ti-25mass%Nb alloy by two-step thermal oxidation is described. The anatase fraction in the TiO2 layer was controlled through process parameters such as the second-step temperature. Finally, photocatalytic activity of TiO2 layers formed on the Ti and Ti alloys is evaluated, including: results of water contact angle, decomposition of methylene blue, and antibacterial effects.

  86. CONTROL OF Ag RELEASE FROM Ag-CONTAINING CALCIUM PHOSPHATES IN SIMULATED BODY FLUID Peer-reviewed

    Ozkan Gokcekaya, Kyosuke Ueda, Takayuki Narushima

    BIOMATERIALS SCIENCE: PROCESSING, PROPERTIES, AND APPLICATIONS V 254 13-20 2015

    Publisher: JOHN WILEY & SONS INC

    DOI: 10.1002/9781119190134.ch2  

    ISSN:1042-1122

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    The dissolution behavior of Ag-containing hydroxyapatite (HA) powders and their sintered compacts in a Tris buffer solution (TBS) with a pH value of 7.4 was investigated. The Ag-containing calcium phosphate powders were prepared by a precipitation method using aqueous solutions. The (Ca+Ag)/P and Ag/(Ca+Ag) atomic ratios in the solutions were set to 1.33 and 1.67 and 0 and 0.10, respectively. The precipitated powders were sintered at 1373 K for 1 d. beta-tricalcium phosphate (TCP) and HA were the main phases of the sintered compacts at (Ca+Ag)/P ratios of 1.33 and 1.67, respectively. Metallic Ag coexisted with HA, and Ag was incorporated into the beta-TCP matrix. Ag ion release was observed in both the as-precipitated powders and the sintered compacts in the TBS. The amount of Ag ion release from the sintered compacts of the beta-TCP matrix was higher than that from the sintered compacts with the HA matrix and metallic Ag particles. The formation of AgCl was confirmed during the immersion of both the as-precipitated powders and the sintered compacts.

  87. Evaluation of Thin Amorphous Calcium Phosphate Coatings on Titanium Dental Implants Deposited Using Magnetron Sputtering Peer-reviewed

    Sou Yokota, Naruhiko Nishiwaki, Kyosuke Ueda, Takayuki Narushima, Hiroshi Kawamura, Tetsu Takahashi

    IMPLANT DENTISTRY 23 (3) 343-350 2014/06

    Publisher: LIPPINCOTT WILLIAMS & WILKINS

    DOI: 10.1097/ID.0000000000000098  

    ISSN:1056-6163

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    Objective: Calcium phosphate is used for dental material because of its biocompatibility and osteoconductivity. Amorphous calcium phosphate (ACP) coatings deposited by magnetron sputtering can control their thickness and absorbability. This study aimed to evaluate and characterize ACP coatings deposited via magnetron sputtering. It was hypothesized that ACP coatings would enhance bone formation and be absorbed rapidly in vivo. Methods: ACP coatings that are 0.5 mu m in thickness were deposited via magnetron sputtering on dental implants. Uncoated implants served as controls. The effect of the ACP coatings in vivo was investigated in New Zealand white rabbit. To evaluate the effect of the ACP coatings on the bone response of the implants, the removal torque, implant stability quotient, and histomorphometric analysis were performed on the implants at 1, 2, and 4 weeks after implantation. Results: Results of the x-ray diffraction analyses confirmed the deposition of ACP coatings. Images from the scanning electron microscopy revealed that the coatings were dense, uniform, and 0.5 mu m in thickness and that they were absorbed completely. Mechanical stability and bone formation in the case of the ACP-coated implants were higher than those of control. Conclusion: These results suggest that implants coated with thin ACP layers improve implant fixation and accelerate bone response.

  88. NKG2D(+) IFN-gamma(+) CD8(+) T Cells Are Responsible for Palladium Allergy Peer-reviewed

    Mitsuko Kawano, Masafumi Nakayama, Yusuke Aoshima, Kyohei Nakamura, Mizuho Ono, Tadashi Nishiya, Syou Nakamura, Yuri Takeda, Akira Dobashi, Akiko Takahashi, Misato Endo, Akiyo Ito, Kyosuke Ueda, Naoki Sato, Shigehito Higuchi, Takeru Kondo, Suguru Hashimoto, Masamichi Watanabe, Makoto Watanabe, Tetsu Takahashi, Keiichi Sasaki, Masanori Nakamura, Takehiko Sasazuki, Takayuki Narushima, Ryuji Suzuki, Kouetsu Ogasawara

    PLOS ONE 9 (2) e86810 2014/02

    Publisher: PUBLIC LIBRARY SCIENCE

    DOI: 10.1371/journal.pone.0086810  

    ISSN:1932-6203

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    Nickel, cobalt, and chromium are well known to be causal agents of allergic contact dermatitis. Palladium (Pd) can also cause allergic disease and exposure results from wide use of this metal in dental restorations and jewelry. Metal allergy is categorized as a delayed-type hypersensitivity, and metal-responsive T cell clones have been isolated from allergic patients. However, compared to nickel, little is known about the pathology of allergic disease mediated by Pd, and pathogenic T cells are poorly understood. To identify the pathogenic T cells that are responsible for onset of Pd allergy, we enriched metal-responsive lymphocytes by sequential adoptive transfer of involved lymph node cells. Here we show that sequential adoptive transfer gradually increased the incidence and the intensity of Pd allergy, and CD8(+) T cells are responsible for the disease as CD8(+) T cell-depleted mice and beta 2-microglobulin-deficient mice did not develop Pd allergy. In addition, we found that draining lymph node cells skewed toward CD8(+) T cells in response to Pd challenge in 8th adoptive transferred recipient mice. The CD8(+) T cells expressed NKG2D, a costimulatory molecule involved in the production of IFN-gamma. NKG2D ligand was also induced in Pd-injected tissues. Furthermore, both NKG2D ligand-transgenic mice, where NKG2D is downmodulated, and IFN-gamma-deficient mice showed impaired Pd allergy. Taken together, these results indicate that IFN-gamma-producing NKG2D(+) CD8(+) T cells are responsible for Pd allergy and suggest that NKG2D is a potential therapeutic target for treatment of metal allergy.

  89. Preparation of calcium pyrophosphate glass-ceramics containing Nb2O5 Peer-reviewed

    Hirotaka Maeda, Tomohiro Miyajima, Sungho Lee, Akiko Obata, Kyosuke Ueda, Takayuki Narushima, Toshihiro Kasuga

    JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 122 (1421) 122-124 2014/01

    Publisher: CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI

    DOI: 10.2109/jcersj2.122.122  

    ISSN:1882-0743

    eISSN:1348-6535

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    New types of calcium phosphate glass-ceramics were prepared with the addition of Nb2O5 to the pyrophosphate region. The glass-ceramics contained alpha-Ca2P2O7, beta-Ca2P2O7, and orthorhombic Nb2O5. The concentrations of Ca, P and Nb elements released from the glass-ceramics were lower than those released from glass of the same chemical composition. Apatite formed on the surface of the glass-ceramics after soaking in 1.5 simulated body fluid for 7 days. The crystal phases of the glass-ceramics improved the chemical durability and apatite forming ability of the material. (C)2014 The Ceramic Society of Japan. All rights reserved.

  90. Precipitate phases and mechanical properties of heat-treated ASTM F 90 Co-Cr-W-Ni alloy Peer-reviewed

    Kosuke Ueki, Kyosuke Ueda, Takayuki Narushima

    ADVANCED CERAMICS AND NOVEL PROCESSING 616 258-262 2014

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/KEM.616.258  

    ISSN:1013-9826

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    The precipitation behavior during heat treatment and resulting mechanical properties of ASTM F 90 Co-20Cr-15W-10Ni (mass%) alloys were investigated with regards to their biomedical applications. Heat treatment was conducted at temperatures of 873 to 1623 K, for a holding time of 259.2 ks. The precipitates produced were then electrolytically extracted from the alloys and analyzed by X-ray diffraction (XRD). This revealed that the precipitates formed were an M23X6 type and/or eta-phase (i.e., an M6X-M12X type). The M23X6-type precipitate was detected across the entire heat-treatment temperature range; however, the.-phase precipitate was only detected at 1073 to 1473 K, becoming dominant at 1173 to 1373 K. The formation of M23X6 type precipitates at 873 K is shown to improve the mechanical properties of this alloy, whereas the domination by the eta-phase precipitate at higher temperatures causes deterioration in the ductility.

  91. Microstructural analysis of biomedical Co-Cr-Mo alloy subjected to high-pressure torsion processing Peer-reviewed

    Murat Isik, Mitsuo Niinomi, Ken Cho, Masaaki Nakai, Junko Hieda, Hakan Yilmazer, Zenji Horita, Takayuki Narushima

    ADVANCED CERAMICS AND NOVEL PROCESSING 616 263-269 2014

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/KEM.616.263  

    ISSN:1013-9826

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    The effect of high-pressure torsion (HPT) processing on the microstructure and Vickers hardness of Co-Cr-Mo (CCM) alloys were investigated in this study. The microstructure of initial CCM alloy contains equiaxed grains with a grain diameter of approximately 50 mu m and twins. The clear grain boundaries of equiaxed grains and twins disappear after HPT processing at a rotation number, N, of 10. The phase maps of initial CCM alloy and CCM alloy subjected to HPT processing at N = 5 measured by electron backscatter diffraction exhibit that the ratio of. phase decreases from 93.5% to 34.1% and the ratio of e phase increases from 6.5% to 65.9% by applying HPT processing. These results indicate that the e phase is formed by high-strain, which is induced by the HPT processing. The Vickers hardness values on the surfaces of the CCM alloys subjected to HPT processing at N = 1, 5, and 10 increase with increasing the equivalent strain, epsilon(eq). These results suggest that an increase of Vickers hardness is correlated to an increase of the ratio of epsilon phase and the dislocation density, and grain refinement, which are caused by the high-strain induced by HPT processing.

  92. Photocatalytic evaluation of anatase layer formed on Ti alloys by thermal oxidation Peer-reviewed

    S. Sado, K. Ueda, T. Narushima, M. Kawano, K. Ogasawara

    Proceedings for International Symposium on Eco Topia Science 2013 1131 2013/11

  93. Ag distribution in calcium phosphates with various Ca/P ratios Peer-reviewed

    O. Gokcekaya, K. Ueda, T. Narushima, C. Ergun

    Proceedings for International Symposium on Eco Topia Science 2013 1113 2013/11

  94. Formation of Anatase on Commercially Pure Ti by Two-Step Thermal Oxidation Using N-2-CO Gas Peer-reviewed

    Nobuyuki Umetsu, Shota Sado, Kyosuke Ueda, Kazuki Tajima, Takayuki Narushima

    MATERIALS TRANSACTIONS 54 (8) 1302-1307 2013/08

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.ME201315  

    ISSN:1345-9678

    eISSN:1347-5320

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    The phase of a TiO2 layer formed on commercially pure Ti by two-step thermal oxidation using N-2-CO gas was investigated. The oxidation process comprised two steps: treatment in an N-2-(0.1, 1 and 5)%CO atmosphere and treatment in air. A Ti(C,N,O) phase was formed after the first-step treatment conducted at 873-1123 K. In the second step, the oxidation of this phase at 573-773 K resulted in the formation of an anatase phase, while its oxidation at 873 K resulted in the formation of a single rutile phase. An increase in the CO partial pressure in the first step lowered the temperature for anatase phase formation. Further, in the second step, a single-phase anatase layer was formed at temperatures of 623 and 673 K.

  95. Preparation of Ag-doped calcium phosphate Peer-reviewed

    O. Gokcekaya, K. Ueda, T. Narushima, C. Ergun

    Proceedings of the 8th Pacific Rim International Congress on Advanced Materials and Processing 1679-1685 2013/08

  96. 金属材料のセラミックスコーティング Peer-reviewed

    成島尚之, 上田恭介

    加工プロセスによる材料機能発現第176委員会 第24回研究会資料 62-81 2013

  97. Phase and Formation/Dissolution of Precipitates in Biomedical Co-Cr-Mo Alloys with Nitrogen Addition Peer-reviewed

    Shingo Mineta, Alfirano, Shigenobu Namba, Takashi Yoneda, Kyosuke Ueda, Takayuki Narushima

    METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE 44A (1) 494-503 2013/01

    Publisher: SPRINGER

    DOI: 10.1007/s11661-012-1399-7  

    ISSN:1073-5623

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    The precipitates in as-cast and heat-treated biomedical Co-28Cr-6Mo-(0 to 0.35)C-(0.15 to 0.25) N alloys (mass pct) were investigated. Heat treatment was carried out at temperatures of 1473 K to 1573 K (1200 degrees C to 1300 degrees C) for holding periods of 0 to 43.2 ks. In the as-cast and heat-treated Co-Cr-Mo-N alloys, no precipitates were detected; nitrogen effectively inhibited the formation of the sigma-phase and stabilized the face-centered cubic (fcc) metallic gamma-phase. The precipitates observed in the as-cast and heat-treated Co-Cr-Mo-C-N alloys were of the M23X6 type, M2X type, pi-phase (M2T3X type with a beta-Mn structure), and eta-phase (M6X-M12X type). Complete precipitate dissolution was detected in the alloys with carbon contents of less than 0.3 mass pct regardless of the nitrogen content. The main precipitates were of the M2X and M23X6 types after heat treatment for 1.8 to 43.2 ks. The pi-phase precipitate was detected in the early stage of heat treatment at high temperatures. The formation of the M2X-type precipitate was enhanced by the addition of nitrogen, although the constitution of the precipitates depended on the balance between the nitrogen and carbon contents and the heat-treatment conditions. DOI: 10.1007/s11661-012-1399-7 (C) The Minerals, Metals & Materials Society and ASM International 2012

  98. Effect of Ba deoxidation on oxygen content in NiTi alloys and non-metallic inclusions Peer-reviewed

    Daisuke Ito, Naruhiko Nishiwaki, Kyosuke Ueda, Takayuki Narushima

    JOURNAL OF MATERIALS SCIENCE 48 (1) 359-366 2013/01

    Publisher: SPRINGER

    DOI: 10.1007/s10853-012-6753-z  

    ISSN:0022-2461

    eISSN:1573-4803

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    The effect of Ba deoxidation on the oxygen content and non-metallic inclusions in NiTi alloys was investigated. The NiTi alloy melt was held in a CaO crucible at 1673 K under Ar gas flow for 0-600 s. Metallic Ba (0.5-1.5 mass% with respect to NiTi alloy melt) was added to the melt. After melting, oxygen content of 710 and 330 mass ppm decreased to 210 and 130 mass ppm, respectively, after a holding time of 300 s after the addition of Ba. The oxygen in the melts was reduced to as low as 64 mass ppm after a second Ba deoxidation. The non-metallic inclusions observed in the NiTi alloys were the Ti4Ni2O (X) and Ti(C,N,O) (X) types. Decreased oxygen content through Ba deoxidation caused a change in the main phase of the non-metallic inclusions from the Ti4Ni2O (X) type to the Ti(C,N,O) (X) type, and a decrease in the area percents of the non-metallic inclusions.

  99. beta-Grain Refinement of alpha+beta-Type Ti-4.5Al-6Nb-2Fe-2Mo Alloy by Using Rare-Earth-Oxide Precipitates Peer-reviewed

    Kyosuke Ueda, Shinichiro Nakaoka, Takayuki Narushima

    MATERIALS TRANSACTIONS 54 (2) 161-168 2013

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MC201207  

    ISSN:1345-9678

    eISSN:1347-5320

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    The effect of the addition of small amounts of rare-earth elements such as La (0.01 mass%), Y (0.1 mass%), Er (0.1 mass%) and Ce (0.1 mass%) on the refinement of beta-grains in an alpha+beta-type Ti-4.5Al-6Nb-2Fe-2Mo alloy was investigated in the temperature range 1173-1573 K. The beta-grain size and the rare-earth-oxide precipitates obtained after heat treatment were evaluated using optical microscopy, scanning electron microscopy, and transmission electron microscopy. Upon heating, alloys exhibited rapid beta-grain growth above a threshold temperature, and this temperature depended on the added rare-earth elements. The fine precipitates of rare-earth oxides formed in the alloy suppressed the beta-grain growth through pinning. Dissolution of the precipitates in the beta-matrix caused rapid beta-grain growth. Yttrium was found to be the most effective element for the suppression of beta-grain growth at high temperatures such as 1573 K.

  100. Mass loss and ion elution of biomedical Co-Cr-Mo alloys during pin-on-disk wear tests Peer-reviewed

    Kyosuke Ueda, Kaori Nakaie, Shigenobu Namba, Takashi Yoneda, Keita Ishimizu, Takayuki Narushima

    Materials Transactions 54 (8) 1281-1287 2013

    DOI: 10.2320/matertrans.ME201316  

    ISSN:1345-9678

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    Pin-on-disk wear tests using biomedical Co-Cr-Mo alloy pins and alumina disks were conducted in Kokubo and 1% lactic acid solutions. The mass loss and elution of metallic ions were measured and the surface of the pin was observed after the wear test. Mass loss of the alloy pins in 1% lactic acid solution was 10 times higher than the mass loss in Kokubo solution. In Kokubo solution, the as-cast pins exhibited higher mass loss and higher total amount of eluted ions than solution-treated pins. The Cr and Mn ion content in Kokubo solution was lower than expected, based on the chemical composition of the alloy. The incorporation of Cr and Mn ions into the calcium phosphate detected on the wear track of disks is the possible reason for the small amount of these ions in Kokubo solution. © 2013 The Japan Institute of Metals and Materials.

  101. RFマグネトロンスパッタリング法による非晶質リン酸カルシウムコーティングの評価

    横田 聡, 栗原 淳, 西脇 成彦, 玉手 総一郎, 上田 恭介, 成島 尚之, 川村 仁, 高橋 哲

    Japanese Journal of Maxillo Facial Implants 11 (3) 243-243 2012/11

    Publisher: (公社)日本顎顔面インプラント学会

    ISSN:1347-894X

  102. Effects of Niobium Ions Released from Calcium Phosphate Invert Glasses Containing Nb2O5 on Osteoblast-Like Cell Functions Peer-reviewed

    Akiko Obata, Yoshiaki Takahashi, Tomohiro Miyajima, Kyosuke Ueda, Takayuki Narushima, Toshihiro Kasuga

    ACS APPLIED MATERIALS & INTERFACES 4 (10) 5684-5690 2012/10

    Publisher: AMER CHEMICAL SOC

    DOI: 10.1021/am301614a  

    ISSN:1944-8244

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    The effects of niobium ions released from 60CaO-30P(2)O(5)-(10-x)Na2O-xNb(2)O(5) (mol %, x = 0-10) glasses on MC3T3-E1 cell functions were evaluated by culture tests with two systems; cell culture on glass plates, or in culture media containing glass extracts. Alkaline phosphatase (ALP) activity in the cells cultured on the glass plates containing 3 and 5 mol 96 of Nb2O5 was significantly higher than that on the Nb2O5-free glass, although proliferation was not enhanced on all glasses containing Nb2O5. Cells cultured in the medium containing 3 X 10(-7) M niobium ions showed the highest ALP activity in comparison with other Nb-containing media or normal medium, regardless of the presence of osteogenic factors (ascorbic acid, beta-glycerophosphate and dexamethasone) in the media. Calcium deposition by the cells cultured in the medium containing 3 x 10(-7) M niobium ions was twice as high as those cultured in medium containing no niobium ions. The effects of niobium ions were thought to depend on ion concentration, and to enhance differentiation and mineralization of osteogenic cells rather than their initial adhesion or proliferation.

  103. Quantitative analyses of osteogenic-differentiation-related gene expressions in human osteoblast-like cells (Saos-2) cultured on hydroxyapatite and titanium Peer-reviewed

    M. Taira, W. Hatakeyama, H. Kihara, H. Kondo, K. Ueda, T. Narushima

    J. Oral Tissue. Engin. 10 (1) 34-41 2012/10/01

    Publisher: Japanese Association of Regenerative Dentistry

    DOI: 10.11223/jarde.10.34  

    ISSN:1348-9623

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    The purpose of this study was to examine osteogenic differentiation behaviors at gene expression levels of osteoblast-like cells (SaOS-2) when cultured on polystyrene (PS), hydoroxyapatite (HAP) and titanium (Ti) for 8, 16 and 24 days, using six primer sets such as those for genes (mRNAs) of glyceraldehyde 3-phosphate dehydrogenase (GAPDH), alkaline phosphatase (ALPL), type 1 collagen (COL1A1), osteopontin (SPP1), bone Sialo protein (IBSP) and osteocalcin precursor (BGLAP). With respect to GAPDH control, ALPL and COL1A1; SPP1 and IBSP; and BGLAP were used as initial-stage, middle-to-late-stage, and last-stage osteogenic differentiation phenotype markers, respectively. Quantitative real-time RT-PCR analyses revealed that HAP most differentiated SaOS-2, followed by Ti while PS did least. It was re-confirmed that with respect to PS, HAP was an excellent osteo-conductive material while Ti also exerted moderate osteo-conductive effects on SaOS-2 in the cell culture condition.

  104. Precipitates in Biomedical Co-28Cr-6Mo-(0-0.41)C Alloys Heat-Treated at 1473 K to 1623 K (1200 degrees C to 1350 degrees C) Peer-reviewed

    Shingo Mineta, Alfirano, Shigenobu Namba, Takashi Yoneda, Kyosuke Ueda, Takayuki Narushima

    METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE 43A (9) 3351-3358 2012/09

    Publisher: SPRINGER

    DOI: 10.1007/s11661-012-1142-4  

    ISSN:1073-5623

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    The phase and formation/dissolution of biomedical Co-28Cr-6Mo-xC (x = 0, 0.12, 0.16, 0.24, 0.33, and 0.41, in mass pct) alloys were investigated before and after heat treatment at high temperatures. The heat-treatment temperatures and holding periods were varied from 1473 K to 1623 K (1200 A degrees C to 1350 A degrees C) and from 0 ks to 43.2 ks, respectively. The intermetallic sigma phase was observed in the as-cast and heat-treated alloys without added carbon. In the carbon-added alloys, the M23C6-type, pi-phase (M2T3X-type carbide with a beta-Mn structure), eta-phase (M6C-M12C-type), and M7C3-type carbides were observed depending on the carbon content and heat-treatment conditions. A complete precipitate dissolution was achieved in the alloys with a carbon content of 0 to 0.24 mass pct. The holding time required for complete precipitate dissolution in the carbon-added alloys increased with increasing heat-treatment temperature above 1548 K (1275 A degrees C). The formation of pi-phase and M7C3-type carbides was observed in the carbon-added alloys during heat treatment at high temperatures of 1548 K to 1623 K (1275 A degrees C to 1350 A degrees C). Two types of pi phase with different lattice constants and chemical compositions were confirmed in the alloys with carbon contents of 0.24, 0.33, and 0.41 mass pct after heat treatment at 1573 K to 1623 K (1300 A degrees C to 1350 A degrees C). The M7C3-type carbide observed at high temperatures occurred in a starlike precipitate with a complicated microstructure.

  105. Biomechanical Evaluation of Amorphous Calcium Phosphate Coated TNTZ Implants Prepared Using a Radiofrequency Magnetron Sputtering System Peer-reviewed

    Naru Shiraishi, Rong Tu, Risa Uzuka, Takahisa Anada, Takayuki Narushima, Takashi Goto, Mitsuo Niinomi, Keiichi Sasaki, Osamu Suzuki

    MATERIALS TRANSACTIONS 53 (7) 1343-1348 2012/07

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.M2012078  

    ISSN:1345-9678

    eISSN:1347-5320

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    Ti-29Nb-13Ta-4.6Zr alloy (TNTZ), a new beta-type Ti alloy, has excellent advantages as a biomaterial, such as low Young's modulus and cytotoxicity, and the absence of allergens. However, it is unclear whether TNTZ can achieve sufficient osseointcgration for it to be used as a dental implant. The effectiveness of surface modification of TNTZ implants by radiofrequency (RF) magnetron sputtering is also unclear. We investigated the biomechanical behaviors of TNTZ implants in vivo, using cylindrical implants of four types: pure Ti, TNTZ, and pure Ti and TNTZ coated with amorphous calcium phosphate (ACP). The implants were inserted in rat femurs, and the femurs were subjected to biomechanical analyses after various time intervals. The results suggest that TNTZ implants can achieve osseointegration similar to that of pure Ti, and that surface modification with ACP by RF magnetron sputtering improves osseointegration, especially in the later stages of healing. doi:10.2320/matertrans.M2012078]

  106. Precipitates in Biomedical Co-Cr-Mo-C-N-Si-Mn Alloys Peer-reviewed

    Alfirano, Shingo Mineta, Shigenobu Namba, Takashi Yoneda, Kyosuke Ueda, Takayuki Narushima

    METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE 43A (6) 2125-2132 2012/06

    Publisher: SPRINGER

    DOI: 10.1007/s11661-011-1009-0  

    ISSN:1073-5623

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    The microstructures of biomedical ASTM F 75/F 799 Co-28Cr-6Mo-0.25C-0.175N-(0 to 1)Si-(0 to 1)Mo alloys (mass pct) were investigated before and after heat treatment, with special attention paid to the effect of nitrogen on the phases and the dissolution of precipitates. The heat treatment temperatures and holding periods employed ranged from 1448 to 1548 K (1175 to 1275 A degrees C) and 0 to 43.2 ks, respectively. A blocky-dense pi-phase precipitate and a lamellar cellular colony, which consisted of an M2X type precipitate and a gamma phase, were mainly detected in the as-cast alloys with and without added Si, respectively. The addition of nitrogen caused cellular precipitation, while the addition of Si suppressed it and enhanced the formation of the pi phase. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses suggested that a discontinuous reaction, i.e., gamma (1) -&gt; gamma (2) + M2X, might be a possible formation mechanism for the lamellar cellular colony. Nitrogen was enriched in the M2X type, eta-phase, and pi-phase precipitates, but was excluded from the M23X6 type precipitate. Complete precipitate dissolution was observed in all of the alloys under varied heat treatment conditions depending on the alloy composition. The addition of nitrogen decreased the time required for complete precipitate dissolution at low heat-treatment temperatures. At high temperatures, i.e., 1548 K (1275 A degrees C), complete precipitate dissolution was delayed by the partial melting that accompanied the formation of the precipitates such as the pi phase resulting in the boundary between the complete and incomplete precipitate dissolution regions in having a C-curved shape.

  107. π-phase and χ-phase: new precipitates in biomedical Co-Cr-Mo alloys Invited Peer-reviewed

    T. Narushima, S. Mineta, Alfirano, K. Ueda

    Interface Oral Health Science 2011 72-80 2012/04

    DOI: 10.1007/978-4-431-54070-0_102  

  108. Calcium phosphate-coated titanium alloy implants prepared by radiofrequency magnetron sputtering: A review Peer-reviewed

    Naru Shiraishi, Yuko Suzuki, Naoko Sato, Takahisa Anada, Takashi Goto, Rong Tu, Mitsuo Niinomi, Takayuki Narushima, Kyosuke Ueda, Risa Uzuka, Osamu Suzuki, Keiichi Sasaki

    Interface Oral Health Science 2011 352-354 2012/01/01

    Publisher: Springer Japan

    DOI: 10.1007/978-4-431-54070-0_102  

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    This review summarized dental implant coated with calcium phosphate films, especially prepared by radiofrequency (RF) magnetron sputtering system. Calcium phosphate films on titanium alloys fabricated by RF magnetron sputtering system have very thin layer (within 500 nm), high bonding strength (over 60 MPa) and excellent biocompatibilities, even though its films created under the condition of room temperature. This method may be providing the effective interface between tissues and some other materials.

  109. Accelerated bone formation around titanium dental implants with amorphous calcium phosphate coating in rabbits Peer-reviewed

    Sou Yokota, Jun Kurihara, Naruhiko Nishiwaki, Soichiro Tamate, Kyosuke Ueda, Takayuki Narushima, Hiroshi Kawamura

    Interface Oral Health Science 2011 243-245 2012/01/01

    Publisher: Springer Japan

    DOI: 10.1007/978-4-431-54070-0_69  

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    The aim of this study was to investigate the bone response of titanium dental implant with amorphous calcium phosphate (ACP) coating film fabricated using RF magnetron sputtering in rabbit. Calcium phosphate coating using RF magnetron sputtering acquires high bonding strength and nanouniformity of films. Moreover, it is reported that ACP was resorbed rapidly in vitro. The ACP-coated and noncoated implants were placed into rabbits. After 1, 2 and 4 weeks of implantation, the implant stability was evaluated by resonance frequency analysis (RFA) and bone formation was also evaluated histomorphometrically. The ACP-coated implants showed higher stability in RFA and improved bone-implant contact ratio in 4 weeks. Titanium dental implant coated with ACP fabricated using RF magnetron sputtering accelerated bone formation compared with that of non coated implants.

  110. Grain Refinement in alpha plus beta-type Ti-4. 5Al-6Nb-2Fe-2Mo Alloys through Precipitation of TiB or Rare Earth Oxides Peer-reviewed

    Yasunori Kimura, Nobuyuki Umetsu, Naomichi Iwata, Shinichiro Nakaoka, Kyosuke Ueda, Takayuki Narushima

    TI-2011: PROCEEDINGS OF THE 12TH WORLD CONFERENCE ON TITANIUM, VOL III 2077-2080 2012

    Publisher: SCIENCE PRESS BEIJING

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    The beta-grain growth in biomedical alpha+beta type Ti-4. 5Al-6Nb-2Fe-2Mo (mass%) alloys with the addition of small amounts of rare earth metals such as La, Y; Ce, and Er and boron was investigated in the beta region of the alloys at temperatures of 1173-1573 K. The addition of Er (0. lmass%), La (0. 01mass%), and Y (0. 1mass %) suppressed the beta-grain coarsening up to heating temperatures of 1273,1373, and 1473 K, respectively; however, this effective suppression of grain growth was not observed in the Ce-added (0. 1mass %) alloy. The marked beta-grain refinement in the Y-added alloy appears to be caused by the relatively high stability of theY(2)O(3) precipitate at high temperatures compared with other rare earth metal oxides. The addition of 0. 003-0. 03mass% boron was effective in suppressing the beta-grain growth, where the effectiveness depended on the content of boron. An increase in the boron content extended the effective temperature range for beta-grain growth suppression. The TiB precipitates were rod-shaped elongated along the forging direction in the beta matrix or small round-shaped.

  111. Two-step Gas Treatment of Commercially Pure Titanium for Anatase Layer Formation Peer-reviewed

    Nobuyuki Umetsu, Takuro Okazumi, Kyosuke Ueda, Takayuki Narushima

    TI-2011: PROCEEDINGS OF THE 12TH WORLD CONFERENCE ON TITANIUM, VOL III 2106-2110 2012

    Publisher: SCIENCE PRESS BEIJING

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    A two-step gas treatment of commercially pure titanium (CP Ti) was investigated with a focus on the formation of the anatase phase. The first step was carried out in Ar-1%C0 atmosphere at 1073 K for 0 ks or in N-2 atmosphere at 1123 K for 14.4 ks. The subsequent second step was carried out in air at 473-873 K for 0 ks and 86.4 ks. A titanium oxycarbide (TiC1-xOx) layer was formed after the first-step treatment in Ar-1% CO atmosphere, and an anatase-rich TiO2 layer was obtained after the second-step treatments in air at 673-873 K for 0 ks and at 573-773 K for 86.4 ks. In particular, single-phase anatase formed under the condition of the second step in air at 573 K for 86.4 ks. The anatase fraction in reaction layer could be controlled by varying the temperature and holding time of the second step. Both the TiN and Ti2N phases were detected as reaction products after the first step in N-2 atmosphere, and an anatase-containing TiO2 layer was obtained after the second-step treatment in air at 723 K for 86.4 ks. The formation of TiN and its oxidation at low temperatures seem to be required for the preparation of an anatase-containing TiO2 layer on Ti.

  112. Deoxidation of NiTi Alloys Using Metallic Barium and their Microstructures Peer-reviewed

    Takayuki Narushima, Daisuke Ito, Kyosuke Ueda

    TI-2011: PROCEEDINGS OF THE 12TH WORLD CONFERENCE ON TITANIUM, VOL III 2050-2053 2012

    Publisher: SCIENCE PRESS BEIJING

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    The Ba deoxidation of NiTi alloy melts with two different levels of initial oxygen content was investigated. Metallic Ba was added to the NiTi alloy melts held in CaO crucibles at 1673 K. The oxygen and Ba contents in the melts were quantitatively measured, and the precipitates in the NiTi alloys were analyzed, based on electrolytic extraction, after cooling in the CaO crucibles. The oxygen contents of the NiTi alloy melts decreased to 131 ppm and to 212 ppm in the NiTi alloy melts with low and high levels of initial oxygen contents, respectively, through the Ba deoxidation. The Ba content in the NiTi alloy melts was less than 10 ppm,120 s after the addition of Ba, independent of the initial oxygen content levels. The content of the precipitates was decreased by the Ba deoxidation. The phase of the precipitates depended on the oxygen and carbon contents in the NiTi alloy melts; the Ba deoxidation changed the phase of the precipitates from Ni2Ti4O and Ti(C, N, O) types to Ti(C, N, O) and from Ni2Ti4O type to Ti(C,N, O) type for NiTi alloys with low and high levels of initial oxygen contents, respectively.

  113. Precipitates in As-Cast and Heat-Treated ASTM F75 Co-Cr-Mo-C Alloys Containing Si and/or Mn Peer-reviewed

    Alfirano, Shingo Mineta, Shigenobu Namba, Takashi Yoneda, Kyosuke Ueda, Takayuki Narushima

    METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE 42A (7) 1941-1949 2011/07

    Publisher: SPRINGER

    DOI: 10.1007/s11661-011-0604-4  

    ISSN:1073-5623

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    The effect of the addition of Si or Mn to ASTM F75 Co-28Cr-6Mo-0.25C alloys on precipitate formation as well as dissolution during solution treatment was investigated. Three alloys-Co-28Cr-6Mo-0.25C-1Si (1Si), Co-28Cr-6Mo-0.25C-1Mn (1Mn), and Co-28Cr-6Mo-0.25C-1Si-1Mn (1Si1Mn)-were heat treated from 1448 K to 1548 K (1175 A degrees C to 1275 A degrees C) for a holding time of up to 43.2 ks. In the case of the as-cast 1Si and 1Si1Mn alloys, the precipitates were M(23)C(6)-type carbide, eta phase (M(6)C-M(12)C-type carbide), and pi phase (M(2)T(3)X-type carbide with a beta-Mn structure), while in the case of the as-cast 1Mn alloy, M(23)C(6)-type carbide and eta phase were detected. The 1Si and 1Si1Mn alloys required longer heat-treatment times for complete precipitate dissolution than did the 1Mn alloys. During the solution treatment, blocky dense M(23)C(6)-type carbide was observed in all the alloys over the temperature range of 1448 K to 1498 K (1175 A degrees C to 1225 A degrees C). At the heat-treatment temperature of 1523 K (1250 A degrees C), starlike precipitates with stripe patterns-comprising M(23)C(6)-type carbide and metallic face-centered-cubic (fcc) gamma phase-were detected in the 1Si and 1Si1Mn alloys. A pi phase was observed in the 1Si and 1Si1Mn alloys heat treated at 1523 K and 1548 K (1250 A degrees C and 1275 A degrees C) and in the 1Mn alloy heat treated at 1548 K (1275 A degrees C); its morphology was starlike-dense. The addition of Si appeared to promote the formation of the pi phase in Co-28Cr-6Mo-0.25C alloys at 1523 K and 1548 K (1250 A degrees C and 1275 A degrees C). Thus, the addition of Si and Mn affects the phase and morphology of the carbide precipitates in biomedical Co-Cr-Mo alloys.

  114. Anatase formation on titanium by two-step thermal oxidation Peer-reviewed

    Takuro Okazumi, Kyosuke Ueda, Kazuki Tajima, Nobuyuki Umetsu, Takayuki Narushima

    JOURNAL OF MATERIALS SCIENCE 46 (9) 2998-3005 2011/05

    Publisher: SPRINGER

    DOI: 10.1007/s10853-010-5177-x  

    ISSN:0022-2461

    eISSN:1573-4803

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    Two-step thermal oxidation of commercially pure Ti was investigated with a focus on the formation of anatase. A first-step treatment was conducted in Ar-(0.1-20)%CO atmosphere at a temperature of 773-1173 K for a holding time of 0 or 86.4 ks, and a subsequent second-step treatment was conducted in air at 473-873 K for 0-86.4 ks. Titanium oxides and titanium oxycarbide were obtained in the first step, with relative amounts depending on heating temperature, holding time, and CO partial pressure. An anatase-rich layer on Ti was obtained after second-step treatment in air at 573-773 K in cases where single-phase titanium oxycarbide formed in the first step. Thus, the formation of single-phase titanium oxycarbide in the first step and temperature control in the second step were required for the formation of an anatase-rich layer. The bonding strength of an anatase-rich layer with a thickness of 0.5 mu m was calculated to be around 90 MPa. This study reveals the conditions under which an anatase-rich layer with excellent adherence to Ti can be prepared by thermal oxidation.

  115. Enhancement of nickel elution by lipopolysaccharide-induced inflammation Peer-reviewed

    Rina Tanaka, Yoshiaki Goi, Kenji Ishihara, Kyosuke Ueda, Takayuki Narushima, Hiroshi Ohtsu, Masahiro Hiratsuka, Noriyasu Hirasawa

    JOURNAL OF DERMATOLOGICAL SCIENCE 62 (1) 50-57 2011/04

    Publisher: ELSEVIER IRELAND LTD

    DOI: 10.1016/j.jdermsci.2010.12.006  

    ISSN:0923-1811

    eISSN:1873-569X

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    Background: Implantations of metallic biomedical devices into bodies are increasing. The elution of Ni ions from these devices can lead to metal allergies. However, the molecular mechanisms of the elution have not been fully examined. Furthermore, it is not clear whether infection and inflammation affect the corrosion of metals. Objective: We examined whether the elution of Ni from metal wires and plates was enhanced by inflammation in vivo and in vitro. Methods: A Ni or SUS316L wire was implanted subcutaneously in the dorsum of mice. Lipopolysaccharide (LPS) was injected at the site immediately following the implantation. After 8, 24, and 72 h, the tissue around the wire was excised. RAW 264 cells were seeded on a Ni plate and incubated for 24 h in medium containing LPS. The amount of Ni in the tissue or conditioned medium was determined fluorometrically. Results: The release of Ni ions from the wire was significantly increased from 8 to 72 h, and further increased by LPS. LPS also enhanced the release of Ni ions by the cells, but only when they were attached to the Ni plate. Chloroquine, bafilomycin A(1) and amiloride markedly inhibited the effects of LPS. Conclusion: The activation of inflammatory cells on metals enhanced the elution of Ni probably via the release of protons at the interface of the cells and material. (C) 2011 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

  116. Assessment of the release of nickel from biomaterials in vivo and in vitro: enhancement by lipopolysaccharide Peer-reviewed

    Rina Tanaka, Yoshiaki Goi, Kenji Ishihara, Kyosuke Ueda, Takayuki Narushima, Hiroshi Ohtsu, K. Ohuchi, Masahiro Hiratsuka, Noriyasu Hirasawa

    Inflam. Regene. 31 (3) 302-306 2011

    Publisher: The Japanese Society of Inflammation and Regeneration

    DOI: 10.2492/inflammregen.31.302  

    ISSN:1880-9693

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    Biodevices are implanted for long periods of time, so the release of metal ions from alloys should be tested in tissues to assess the risk of inducing metal allergies. However there is little evidence that the release of metal ions from alloys <I>in vivo</I> is similar to that <I>in vitro</I>. We implanted metal wires in mice and determined the concentration of metal ions in tissue to analyze the mechanisms responsible for metal allergies. The release of ions from the Ni wire was detected within 8 h and attained a plateau 72 h after the implantation. Furthermore, it was significantly increased by an injection of LPS. The results indicated that the release of Ni was apparently enhanced by inflammatory responses. We also established an <I>in vitro</I> assay system using the murine macrophage cell line RAW 264. The addition of LPS apparently increased the amount of Ni released into the medium, indicating the activation of the cells to have enhanced the elution of ions from the Ni plate. Our <I>in vitro</I> model using LPS-stimulated RAW264 cells might reflect the elution of Ni in inflamed tissue.

  117. Alkali Hydrothermal Synthesis of Zeolite A Using Oxide By-products Peer-reviewed

    Taichi Murakami, Yoshiyuki Sugano, Tsunetoshi Kinami, Takayuki Narushima, Yasutaka Iguchi, Chiaki Ouchi

    ISIJ INTERNATIONAL 51 (1) 158-165 2011

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.51.158  

    ISSN:0915-1559

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    The alkali hydrothermal synthesis of zeolite A using oxide by-products such as blast furnace (BF) slag and aluminum dross was investigated. Na-P1 (Na(6)Al(6)Si(6)O(32) center dot 12H(2)O) was synthesized directly in NaOH aqueous solution for 86.4 ks at 373 K using BF slag, Al(2)O(3), and SiO(2). On the other hand, zeolite A was successfully synthesized by a two-step method including an elution treatment of Al(2)O(3). Under optimal conditions, the formation ratio of zeolite A in various compounds contained in the product was 56 %. The utilization of dross residue squeezed out from the aluminum dross as a raw material to synthesis of zeolite A let this ratio increase to 60 %. The heat of water adsorption of the product synthesized by the two-step method using BF slag, SiO(2), and aluminum dross residue was measured, and it was 184 J/g, being higher than that of commercial zeolite A.

  118. Recovery of Calcium from BF Slag and Synthesis of Zeolite A Using Its Residue Peer-reviewed

    Taichi Murakami, Yoshiyuki Sugano, Takayuki Narushima, Yasutaka Iguchi, Chiaki Ouchi

    ISIJ INTERNATIONAL 51 (6) 901-905 2011

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.51.901  

    ISSN:0915-1559

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    The elution and recovery of Ca from blast furnace slag and the alkali hydrothermal synthesis of zeolite A using the residue from the elution treatment were investigated using a ball-milling-type reaction vessel. The superior elution was obtained by using citric and formic acid solutions from which Ca could be selectively eluted from the slag. Whereas hydrochloric acid solution and ion-exchanged water were ineffective for Ca elution. Ca ions eluted in the solution were recovered as calcium formate by evaporation of water. From the formic acid eluted slag residue after three elution treatment cycles of the slag for 7.2 ks, zeolite A was synthesized in 1 mol/L NaOH solution with a reaction time of 86.3 ks at 343 K, without the addition of any other materials.

  119. Precipitates in Biomedical Co-Cr-Mo-C-Si-Mn Alloys Peer-reviewed

    T. Narushima, Alfirano, S. Mineta, S. Namba, T. Yoneda, K. Ueda

    ADVANCED MATERIALS RESEARCH QIR 12 277 51-+ 2011

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/AMR.277.51  

    ISSN:1022-6680

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    The phase and dissolution behavior of precipitates in biomedical ASTM F75 Co-Cr-Mo-C-Si-Mn alloys were investigated. Alloys of five different compositions, Co-28Cr-6Mo-0.25C-1Si, Co-28Cr-6Mo-0.25C-1Mn, Co-28Cr-6Mo-0.25C-1Si-1Mn, Co-28Cr-6Mo-0.15C-1Si, and Co-28Cr-6Mo-0.35C-1Si, were heat-treated from 1448 to 1548 K. The precipitates observed in the as-cast and heat-treated alloys were carbides (M23C6 type, eta-phase, and pi-phase) and an intermetallic compound (pi-phase). The main precipitates observed after heat treatment at high temperatures such as 1548 K were pi-phase and M23C6 type carbide. At these high temperatures, two types of starlike precipitates-dense and stripe-patterned-were observed. The starlike-dense precipitate was the pi-phase, and the starlike precipitate with a stripe pattern was identified as the M23C6 type carbide and metallic fcc gamma-phase. In the alloys heat-treated at 1448 to 1498 K, blocky-dense M23C6 type carbide was primarily observed. chi-phase was detected in the Co-28Cr-6Mo-0.15C-1Si alloy under as-cast condition and after heat treatment at 1448-1523 K for a short holding time. The addition of Si seemed to increase the holding time for complete precipitate dissolution because of the effects of Si on the promotion of pi-phase formation at high temperatures and the increased carbon activity in the metallic matrix.

  120. Surface modification of titanium by pack cementation treatment using calcium phosphate powders for biomedical applications Peer-reviewed

    Kyosuke Ueda, Hajime Suto, Takayuki Narushima

    METALS AND MATERIALS INTERNATIONAL 16 (4) 569-572 2010/08

    Publisher: KOREAN INST METALS MATERIALS

    DOI: 10.1007/s12540-010-0808-y  

    ISSN:1598-9623

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    The surface modification of commercially pure titanium by pack cementation treatment using hydroxyapatite (HAp) or tetracalcium phosphate (TTCP) powder was investigated for temperatures ranging from 773 K to 1073 K. An HAp phase was detected on the surface of the titanium substrates after pack cementation treatment at temperatures of 973 K and 1073 K. After treatment using HAp and TTCP powders, a reaction layer with small HAp particles and pores containing small HAp particles, respectively, was observed. Apatite crystallites with a network pattern formed on the pack-cementation-treated titanium substrates after the substrates were immersed in Kokubo solution for 43.2 ks; such rapid apatite formation suggests that pack cementation treatment improves the biocompatibility of titanium.

  121. Carbide Formation and Dissolution in Biomedical Co-Cr-Mo Alloys with Different Carbon Contents during Solution Treatment Peer-reviewed

    Shingo Mineta, Shigenobu Namba, Takashi Yoneda, Kyosuke Ueda, Takayuki Narushima

    METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE 41A (8) 2129-2138 2010/08

    Publisher: SPRINGER

    DOI: 10.1007/s11661-010-0227-1  

    ISSN:1073-5623

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    The microstructures of as-cast and heat-treated biomedical Co-Cr-Mo (ASTM F75) alloys with four different carbon contents were investigated. The as-cast alloys were solution treated at 1473 to 1548 K for 0 to 43.2 ks. The precipitates in the matrix were electrolytically extracted from the as-cast and heat-treated alloys. An M(23)C(6) type carbide and an intermetallic sigma phase (Co(Cr,Mo)) were detected as precipitates in the as-cast Co-28Cr-6Mo-0.12C alloy; an M(23)C(6) type carbide, a sigma phase, an eta phase (M(6)C-M(12)C type carbide), and a pi phase (M(2)T(3)X type carbide with a beta-manganese structure) were detected in the as-cast Co-28Cr-6Mo-0.15C alloy; and an M(23)C(6) type carbide and an eta phase were detected in the as-cast Co-28Cr-6Mo-0.25C and Co-28Cr-6Mo-0.35C alloys. After solution treatment, complete precipitate dissolution occurred in all four alloys. Under incomplete precipitate dissolution conditions, the phase and shape of precipitates depended on the heat-treatment conditions and the carbon content in the alloys. The pi phase was detected in the alloys with carbon contents of 0.15, 0.25, and 0.35 mass pct after heat treatment at high temperature such as 1548 K for a short holding time of less than 1.8 ks. The presence of the pi phase in the Co-Cr-Mo alloys has been revealed in this study for the first time.

  122. Fabrication and evaluation of multi-layered calcium phosphate coating film on titanium Peer-reviewed

    Kyosuke Ueda, Yuuki Kawasaki, Takashi Goto, Jun Kurihara, Hiroshi Kawamura, Takayuki Narushima

    Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 57 (5) 314-320 2010/05

    DOI: 10.2497/jjspm.57.314  

    ISSN:0532-8799

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    Double-layered calcium phosphate coating films consisting of layers with different crystallinity and composition were fabricated on titanium substrates by RF magnetron sputtering. The first layer of the double-layered coating film, i.e., the inner layer, was made of calcium phosphate having high crystallinity, the second layer, i.e., the outer layer, was made of calcium phosphate having low crystallinity. A double-layered HAp/OAp coating film was fabricated on the titanium substrate as an inner layer, an HAp film was prepared on the titanium substrate by heat treatment of an OAp film in air at 873 K for 7.2 ks, and then, the HAp layer was coated with the OAp film. In the fabrication of a double-layered OAp/ACP coating film, the inner OAp and the outer ACP films were coated on the titanium substrate under different sputtering conditions. The thickness of the single layer was controlled to be 0.5 μm, and the total thickness of these double-layered coating films was around 1 μm. The coating film that comprises the double-layer was dense with a uniform thickness, and the two layers were in close contact with each other. The bonding strength of the HAp/OAp coating film was greater than 50 MPa. As in vivo evaluation, the removal torque of HAp/OAp-coated titanium implants from the femur of Japanese white rabbits was measured. The value of this torque was considerably higher than that of the removal torque of non-coated titanium implants. The outer OAp layer with low crystallinity appeared to dissolve after the 4-week implantation, while the inner HAp layer remained intact and was directly attached to the new bone.

  123. S0201-1-2 Formation of anatase film on titanium and its evaluation of bone compatibility

    NARUSHIMA Takayuki, UEDA Kyosuke, OKAZUMI Takuro

    The proceedings of the JSME annual meeting 2010 13-14 2010

    Publisher: The Japan Society of Mechanical Engineers

    DOI: 10.1299/jsmemecjo.2010.5.0_13  

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    The oxide phase on Ti, TiO_2, is known to affect their properties. Anatase has been suggested to have excellent bone forming ability as compared to rutile. The anatase layer formation on Ti and its alloys by thermal oxidation could be the low-cost and simple surface treatment for improving their bone compatibility. We developed the two-step thermal oxidation process for the anatase layer formation on CP Ti. At the first-step, CP Ti is heat-treated in an Ar-CO atmosphere. At the second-step, the specimens were oxidized in air, and anatase-rich layer was obtained in the case of that oxycarbide (TiC_xO_y) single phase was formed at the first-step. The immersion tests in simulated body fluid showed that the anatase-rich layer improved the bone compatibility of CP Ti. The bonding strength between the anatase-rich layer and CP Ti was higher than 90 MPa.

  124. New-generation metallic biomaterials Peer-reviewed

    T. Narushima

    Metals for Biomedical Devices 355-378 2010

    Publisher: Elsevier Ltd

    DOI: 10.1533/9781845699246.4.355  

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    In this chapter, the current status of metallic biomaterials and the research and development of new-generation metallic biomaterials are discussed. First, the traditional metallic biomaterials are reviewed. The alloy design and properties of the new metallic biomaterials and the new processing technologies used in fabricating porous metallic biomaterials and in grain refining are then discussed. This chapter focuses on the following metallic biomaterials: stainless steels, cobalt (Co)-chromium (Cr) alloys, titanium (Ti) and its alloys, magnesium (mg) alloys, and bulk metallic glasses. Finally, the future trends in new-generation metallic biomaterials are presented. © 2010 Woodhead Publishing Limited All rights reserved.

  125. Preparation of functionally graded bio-ceramic film by MOCVD Peer-reviewed

    Mitsutaka Sato, Rong Tu, Takashi Goto, Kyosuke Ueda, Takayuki Narushima

    MULTISCALE, MULTIFUNCTIONAL AND FUNCTIONALLY GRADED MATERIALS 631-632 193-+ 2010

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/MSF.631-632.193  

    ISSN:0255-5476

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    Functionally graded Ca-Ti-O/Ca-P-O films were prepared by MOCVD. The phases, composition and morphology of Ca-Ti-O and Ca-P-O films changed depending on the molar ratio of each precursors, total pressure (P-tot) and substrate temperature (T-sub). CaTiO3 films in a single phase were obtained at T-sub = 973 and 1073 K. CaTiO3 films prepared at 873 K had a dense and smooth surface, whereas that prepared at T-sub = 1073 K had complicated rough surface with a cauliflower-like texture. The graded texture of CaTiO3 films from columnar to fine grains was advantageous to good adherence for metal substrates. alpha-TCP and HAp films in a single phase were obtained at T-sub = 973 and 1073 K. Both alpha-TCP and HAp films had a dense and smooth surface. The maximum deposition rate of Ca-Ti-O and Ca-P-O films were 44 and 20 mu m/h, respectively, and several 10 times grater than that of sputtering method. Apatite formation rate strongly depended on the surface morphology of film. Apatite formed after 3 days on the CaTiO3 film, 14 days on the alpha-TCP film and 6 hours on the HAp film in a Hanks' solution.

  126. Calcium Phosphate Coating on Blast-treated Titanium Implants by RF Magnetron Sputtering Peer-reviewed

    K. Ueda, T. Narushima, T. Goto, T. Katsube, H. Nakagawa, H. Kawamura, M. Taira

    MULTISCALE, MULTIFUNCTIONAL AND FUNCTIONALLY GRADED MATERIALS 631-632 211-+ 2010

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/MSF.631-632.211  

    ISSN:0255-5476

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    Calcium phosphate coating films were fabricated on Ti-6Al-4V plates and screw-type implants with a blast-treated surface using radiofrequency (RF) magnetron sputtering and were evaluated in vitro and in vivo. Amorphous calcium phosphate (ACP) and oxyapatite (OAp) films obtained in this study could cover the blast-treated substrate very efficiently, maintaining the surface roughness. For the in vitro evaluations of the calcium phosphate coating films, bonding strength and alkaline phosphatase (ALP) activity were examined. The bonding strength of the coating films to a blast-treated substrate exceeded 60 MPa, independent of film phases except for the film after post-heat-treatment in silica ampoule. When compared with an uncoated substrate, the increase in the ALP activity of osteoblastic SaOS-2 cells on a calcium phosphate coated substrate was confirmed by a cell culture test. The removal torque of screw-type Ti-6Al-4V implants with a blast-treated surface from the femur of Japanese white rabbit increased with the duration of implantation and it was statistically improved by coating an ACP film 2 weeks after implantation. The in vitro and in vivo studies suggested that the application of the sputtered ACP film as a coating on titanium implants was effective in improving their biocompatibility with bones.

  127. Changes in microstructure of biomedical Co-Cr-Mo-C alloys with solution treating and aging Peer-reviewed

    S. Mineta, S. Namba, T. Yoneda, K. Ueda, T. Narushima

    THERMEC 2009 SUPPLEMENT 89-91 377-+ 2010

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/AMR.89-91.377  

    ISSN:1022-6680

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    Microstructural changes occurring in biomedical Co-Cr-Mo alloys with three carbon levels due to solution treatment and aging were investigated. Ingots of Co-Cr-Mo alloys with three different carbon levels were prepared by vacuum furnace melting; their chemical composition was Co-28Cr-6Mo-xC (x = 0.12, 0.25 and 0.35 mass%). Precipitates were electrolytically extracted from as-cast and heat-treated alloys. An M23C6 type carbide and a sigma phase were detected as precipitates in as-cast Co-28Cr-6Mo-0.12C alloy, and an M23C6 type carbide and an eta phase (M6C-M12C type carbide) were detected in as-cast Co-28Cr-6Mo-0.25C and Co-28Cr-6Mo-0.35C alloys. Only the M23C6 type carbide was detected during solution treatment. Complete precipitate dissolution occurred in all the three alloys after solution treatment. The holding time required for complete precipitate dissolution increased with increasing carbon content and decreasing solution treatment temperature. Complete precipitate dissolution occurred in the Co-Cr-Mo-C alloys solution treated at 1523 K for 43.2 ks; they were then subjected to aging from 873 to 1473 K for a heating time up to 44.1 ks after complete precipitate dissolution in solution treatment at 1523 K for 43.2 ks. The M23C6 type carbide with a grain size of 0.1-3 mu m was observed after aging. A time-temperature-precipitation diagram of the M23C6 type carbide formed in the Co-28Cr-6Mo-0.25C alloy was plotted.

  128. Microscopic observations and inflammatory cytokine productions of human macrophage phagocytising submicron titanium particles Peer-reviewed

    Masayuki Taira, Tadayoshi Kagiya, Hidemitsu Harada, Minoru Sasaki, Shigenobu Kimura, Takayuki Narushima, Takashi Nezu, Yoshima Araki

    JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE 21 (1) 267-275 2010/01

    Publisher: SPRINGER

    DOI: 10.1007/s10856-009-3834-x  

    ISSN:0957-4530

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    This study was performed to microscopically observe and measure inflammatory cytokine production by human macrophages phagocytosing submicron titanium (Ti) particles. Observations with secondary electron microscopy (SEM), SEM/electron probe microanalysis (EPMA) and transmission electron microscopy (TEM) indicated that macrophages [phorbol-12-myristate-13-acetate (PMA)-differentiated THP-1 cells] at 24 h in culture actively phagocytosed and accumulated submicron Ti particles in intracellular phagosomes, in which refinement of Ti particles occurred. The macrophages were also cultured for 24 h in four media with and without submicron Ti particles and lipopolysaccharide (LPS; components of bacteria). Whilst neither stimulus reduced cell viability, submicron Ti particles and LPS activation independently and synergistically caused the macrophages to produce three inflammatory cytokines (TNF-alpha, IL-1 beta and IL-6) at high levels in the culture supernatants. The inflammatory and osteolysis conditions caused by macrophages phagocytosing submicron Ti particles would be worsened by challenge with LPS in patients wearing Ti prostheses.

  129. Phase and Morphology of Carbides in ASTM F75 Co-Cr-Mo-C Alloys Formed at 1473 to 1623 K Peer-reviewed

    Shingo Mineta, Alfi Rano, Shigenobu Namba, Takashi Yoneda, Kyosuke Ueda, Takayuki Narushima

    PRICM 7, PTS 1-3 654-656 2176-+ 2010

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/MSF.654-656.2176  

    ISSN:0255-5476

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    The phase and morphology of precipitates in heat-treated Co-28Cr-6Mo-xC (x = 0.12, 0.15, 0.25, and 0.35mass%) alloys were investigated. The as-cast alloys were solution-treated in the temperature range of 1473 to 1623 K for 0 to 43.2 ks. Complete precipitate dissolution was observed in all four alloys, each of which had different carbon contents. The holding time for complete dissolution was greater for alloys with greater carbon content. The curve representing the boundary between the complete- and incomplete-dissolution conditions for each alloy is C shaped. Under the incomplete precipitate dissolution conditions of the Co-28Cr-6Mo-0.25C alloy, an M23C6 type carbide and a pi-phase (M2T3X type carbide with beta-Mn structure) were observed at 1548 to 1623 K, and starlike precipitates with a stripe pattern and with a dense appearance were both observed; the former comprised the M23C6 type carbide + gamma-phase, and the latter was the pi-phase. In contrast, only a blocky-dense M23C6 type carbide was observed at 1473 to 1523 K.

  130. Heat Treatment of ASTM F75 Co-Cr-Mo-C-Si-Mn Alloys Peer-reviewed

    Alfirano, Shingo Mineta, Shigenobu Namba, Takashi Yoneda, Kyosuke Ueda, Takayuki Narushima

    PRICM 7, PTS 1-3 654-656 2180-+ 2010

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/MSF.654-656.2180  

    ISSN:0255-5476

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    In this study, the carbide dissolution and formation of biomedical Co-28Cr-6Mo-0.25C-1Si (1Si) and Co-28Cr-6Mo-0.25C-1Mn (1Mn) alloys occurring during solution treatment and aging were investigated. The addition of Si or Mn markedly affected the behavior of precipitates during heat treatment. The alloy with added Si required a longer solution treatment time for complete precipitate dissolution as compared to the alloy with added Mn. Blocky M23C6-type carbide was observed during solution treatment at 1448-1523 K. Starlike precipitates were observed in the I Si and 1Mn alloys at 1523-1548 K and 1523 K, respectively. The starlike precipitates exhibited two types of morphologies: dense and stripe patterned. The starlike precipitates with dense and stripe-patterned appearances were a pi-phase and M23C6-type carbide + metallic gamma-phase, respectively. An M23C6-type carbide and an eta-phase were formed during the aging of both the 1Si and the 1Mn alloys. In addition, an intermetallic sigma-phase was detected during the aging of the 1Si alloy at 1373 K.

  131. Pack Cementation Treatment of Titanium Using Tetracalcium Phosphate Powder for Biomedical Applications Peer-reviewed

    Kyosuke Ueda, Hajime Suto, Kaori Nakaie, Takayuki Narushima

    PRICM 7, PTS 1-3 654-656 2172-2175 2010

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/MSF.654-656.2172  

    ISSN:0255-5476

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    The surface modification of commercially pure titanium (CP Ti) by pack cementation treatment at 973 K using tetracalcium phosphate (Ca(4)(PO(4))(2)O, TTCP) slurry was investigated. An HAp phase and a CaTiO(3) phase were observed on the reaction layer of the CP Ti substrate after pack cementation treatment at 973 K for 86.4 ks. TTCP powder decomposed to HAp and CaO, and CaO reacted with TiO(2) to form CaTiO(3). The reaction layer on the CP Ti substrate consisted of inner and outer layers and the particles were in the outer reaction layer. The pores observed on the reaction layer were formed by the detachment of particles from the outer layer. The bonding strength of the reaction layer was 68.1 MPa. Apatite completely covered the surface of the pack-cementation-treated CP Ti after immersion in Kokubo solution for 21.6 ks; such rapid apatite formation suggests that pack cementation treatment improves the biocompatibility of titanium.

  132. Calcium Phosphate Coating on Titanium Using Dry Process Peer-reviewed

    Takayuki Narushima, Kyosuke Ueda, Takashi Goto, Jun Kurihara, Hiroshi Kawamura

    PRICM 7, PTS 1-3 654-656 2162-+ 2010

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/MSF.654-656.2162  

    ISSN:0255-5476

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    Oxyapatite, amorphous calcium phosphate, and double-layered calcium phosphate coating films were fabricated on mirror-polished commercially pure titanium (CP Ti) and blasted Ti-6Al-4V alloy substrates by radiofrequency (RF) magnetron sputtering; the properties of these films were evaluated in vivo and in vitro. The bonding strength between the calcium phosphate films and the Ti substrates was higher than 50 MPa. This value is higher than the bonding strength reported in the case of plasma-sprayed calcium phosphate coating films fabricated on Ti substrates. The removal torque of screw-type blasted Ti-6Al-4V alloy implants in the femurs of Japanese white rabbits increased with the duration of implantation, and the removal torque values of the coated implants was observed to be higher than those of the non-coated implants. In vitro and in vivo studies indicate that coating Ti implants with calcium phosphate films using RF magnetron sputtering is effective in improving the bone compatibility of Ti implants. Finally, the factors that should be considered in fabricating biomedical coating films were discussed.

  133. Effect of yttrium addition on grain growth of alpha, beta and alpha plus beta titanium alloys Peer-reviewed

    B. Poorganji, A. Kazahari, T. Narushima, C. Ouchi, T. Furuhara

    15TH INTERNATIONAL CONFERENCE ON THE STRENGTH OF MATERIALS (ICSMA-15) 240 012170 2010

    Publisher: IOP PUBLISHING LTD

    DOI: 10.1088/1742-6596/240/1/012170  

    ISSN:1742-6588

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    In this study effects of small amount of yttrium addition on grain growth of C. P titanium (single alpha), Ti-14Mo-3Nb-1.5Zr (single beta) and a newly developed Ti-4.5Al-6Nb-2Mo-2Fe (alpha+beta) titanium alloy are investigated. By adding yttrium nano-sized Y(2)O(3) particles are formed in &apos;in-situ&apos; mode. These particles lead to significant suppression of grain growth in single alpha and beta alloys rather than in the alpha+beta alloy. The results are discussed with regard to conventional grain growth and grain boundary pinning models. It is concluded that yttrium is a potential micro alloying element in titanium alloys and could be used as a grain refining agent.

  134. Oxygen Distribution in Titanium Single Crystal Fabricated by Optical Floating-Zone Method under Extremely Low Oxygen Partial Pressure Peer-reviewed

    Koji Hagihara, Takahiro Tachibana, Keita Sasaki, Yoshiyuki Yoshida, Naoki Shirakawa, Tohru Nagasawa, Takayuki Narushima, Takayoshi Nakano

    MATERIALS TRANSACTIONS 50 (12) 2709-2715 2009/12

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MA200903  

    ISSN:1345-9678

    eISSN:1347-5320

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    This study examines the properties of a titanium single crystal fabricated by the floating-zone-melting process in Ar gas flow atmosphere where the partial pressure of oxygen was maintained extremely low at P-O2 = similar to 10(-23) atm by the newly developed oxygen pump system. The distribution of solute oxygen atoms in the obtained single crystal exhibited a peculiar gradient. In the early stage of the titanium single crystal growth, the oxygen content in the single crystal (approximately 1600 ppm) was higher than that in the mother ingot (980 ppm). However, as the crystal growth progressed. the oxygen content gradually decreases and then reduced to 660 ppm in the final stage of crystal growth. Such a gradient of oxygen composition was not detected in titanium single crystals fabricated under conventional, commercial Ar gas flow atmosphere. owing to the unique gradient of oxygen content formed under extremely low oxygen partial pressure, the Vickers hardness of the single crystal decreased gradually along the crystal growth direction. [doi: 10.2320/matertrans.MA200903]

  135. Surface Hardening Treatment for Titanium Materials Using Ar-5%CO Gas in Combination with Post Heat Treatment under Vacuum Peer-reviewed

    Y. Z. Kim, Takashi Konno, Taichi Murakami, Takayuki Narushima, Chiaki Ouchi

    MATERIALS TRANSACTIONS 50 (12) 2763-2771 2009/12

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MA200911  

    ISSN:1345-9678

    eISSN:1347-5320

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    Surface hardening using solute oxygen formed by the dissociation of titanium oxide (TiO2) layer on commercially pure (C.P.) titanium, alpha + beta type Ti-4.5Al-3V-2Fe-2Mo (SP-700) alloy, and beta type Ti-15Mo-5Zr-3Al (Ti-15-53) alloy was investigated. This method consists of two steps: surface hardening using Ar-5%CO gas for a short time period and subsequent heat treatment under vacuum. Both treatments were carried out at 1073 K. The maximum Surface hardness and hardening layer depth for C.P. titanium obtained by surface hardening in Ar-5%CO gas for 1.8 ks were 420 Hv and 30 mu m, respectively. After post heat treatment for 14.4 ks, these values increased to 820 Hv and 70 mu m, respectively. The increase of surface hardening achieved by post heat treatment was yielded by solid solution hardening of oxygen via the following steps. Solute oxygen was continuously formed at the oxide layer/titanium interface by the dissociation of the oxide layer formed during surface hardening treatment. Oxygen then diffused into titanium matrix, which resulted in solid solution hardening. The highest and lowest values of the maximum surface hardness were obtained in C.P. titanium and Ti-15-53 alloy, respectively. On the other hand, the hardening layer depth was largest for Ti-15-53 alloy and smallest for C.P. titanium. These results can be explained by the differences in solubility and diffusivity of oxygen between the titanium a phase and phase. This two-step process appears to be a beneficial industrial surface hardening method for titanium materials because it enables the removal of the oxide layer while yielding surface hardness comparable to that obtained by the one-step process under the same total heat-treating time. [doi: 10.2320/matertrans.MA200911]

  136. Behavior of Precipitates in Biomedical Co-Cr-Mo-C Alloys during Heat Treatment Peer-reviewed

    S. Mineta, Alfirano, S. Namba, T. Yoneda, K. Ueda, T. Narushima

    Proceedings of Processing and Fabrication of Advance Materials 2009/12

  137. Effect of Addition of Alloying Elements on Microstructure of Biomedical Co-Cr-Mo Alloy Peer-reviewed

    Alfirano, S. Mineta, S. Namba, T. Yoneda, K. Ueda, T. Narushima

    Proceedings of Processing and Fabrication of Advance Materials 2009/12

  138. Surface modification of titanium by dry process for biomedical applications Peer-reviewed

    T. Narushima, K. Ueda, T. Goto

    Proceedings of the 9th International Symposium on Biomaterials 22-27 2009/10/29

  139. Precipitation Behavior in a Hanks' Solution on Ca-P-O Films Prepared by Laser CVD Peer-reviewed

    Mitsutaka Sato, Rong Tu, Takashi Goto, Kyosuke Ueda, Takayuki Narushima

    MATERIALS TRANSACTIONS 50 (10) 2455-2459 2009/10

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.M2009160  

    ISSN:1345-9678

    eISSN:1347-5320

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    Ca-P-O films were prepared by laser CVD using Ca(dpm)(2) and (C6H5O)(3)PO metal organic precursors. The crystal phase of Ca-P-O films changed depending on deposition temperature (T-deP), total pressure (P-tot), laser power (P-L) and molar ratio of Ca to P (R-Ca/P). beta-TCP films in a single phase were obtained in a P-rich and high T-dep region, while HAp films in a single phase were obtained in a Ca-rich and low T-dep region. The beta-TCP films had a (220) orientation with an elongated and angular roof-shaped surface texture, whereas HAp films had a (300) orientation with a granular surface texture. Both the beta-TCP film and the HAp film had a dense cross section. The Ca-P-O films were immersed in a Hanks' solution for 6 h to 7 d. Particle-shaped precipitates were observed on the beta-TCP and HAp films after 3 d immersion. Needle-shaped precipitates covered the whole surface of HAp film after 7 d immersion. [doi:10.2320/matertrans.M2009160]

  140. Fatigue Behaviors of Ultra Fine Wires of beta-Type and alpha-Type Titanium Alloys Peer-reviewed

    Satoshi Yonezawa, Takayuki Narushima, Kyosuke Ueda, Hisamichi Kimura, Chiaki Ouchi, Yasutaka Iguchi

    MATERIALS TRANSACTIONS 50 (7) 1713-1719 2009/07

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MF200920  

    ISSN:1345-9678

    eISSN:1347-5320

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    Fatigue behaviors of ultra fine wires of beta-type Ti-14Mo-3Nb-1.5Zr alloy and alpha-type Ti-10Zr alloy and alpha-type CP (commercially pure) titanium with diameters in the range of 35-100 mu m were investigated by rotating-bending fatigue testing in 1 mass% lactic acid solution maintained at 310 K. The maximum number of cycles during fatigue testing was 10(7). The beta-type Ti-14Mo-3Nb-1.5Zr alloy wires showed a clear fatigue limit. On the other hand, the alpha-type Ti-10Zr alloy wire and alpha-type CP titanium wire did not show a clear fatigue limit, and their fatigue strengths gradually decreased with decreasing maximum bending stress. The fatigue limit of a beta-type Ti-14Mo-3Nb-1.5Zr alloy wire with a polished surface was greater than 50% of its tensile strength, while the fatigue limits of titanium wires with as-drawn surfaces were less than 50% of their tensile strengths. Surface defects that were introduced during the cold drawing process of the wires might act as crack origins of the fatigue fracture. Therefore, surface polishing is an effective technique for improving fatigue properties of titanium wires. The elution of metallic ions from the wires into the I mass% lactic acid solution was suppressed at a very low level during fatigue testing of all the investigated titanium wires. [doi:10.2320/matertrans.MF200920]

  141. Apatite formation behavior on bio-ceramic films prepared by MOCVD Peer-reviewed

    Mitsutaka Sato, Rong Tu, Takashi Goto, Kyosuke Ueda, Takayuki Narushima

    JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 117 (1364) 461-465 2009/04

    Publisher: CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI

    DOI: 10.2109/jcersj2.117.461  

    ISSN:1882-0743

    eISSN:1348-6535

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    Calcium titanate (CaTiO3), alpha-tricalcium phosphate (alpha-TCP) and hydroxyapatite (HAp) films were prepared by metal-organic chemical vapor deposition (MOCVD) using Ca(dpm)(2), Ti(O-i-Pr)(2)(dpm)(2) and (C6H5O3)PO precursors. The phases, composition and surface morphology of these films changed depending on substrate temperature (T-sub), total pressure (P-tot) and molar ratio of each precursors (R-Ca/Ti, R-Ca/P). The surface morphology of CaTiO3 films changed from granular structure to cauliflower-like texture, and its cross-sectional morphology changed from dense to columnar structure with increasing T-sub alpha-TCP and HAp films had granular surface and dense cross-sectional morphology. CaTiO3, alpha-TCP and HAp films were immersed in a Hanks' solution for 28 d. Apatite formation rate strongly depended on the surface morphology of CaTiO3 film, and apatite covered CaTiO3 film having a granular surface after 4 w while CaTiO3 film having a cauliflower-like texture after 3 d. Apatite covered alpha-TCP films after 14 d and HAp films after 6 h, respectively. HAp films prepared by MOCVD were promising as bone conductive materials. (C) 2009 The Ceramic society of Japan. All rights reserved.

  142. Gene expression analyses of human macrophage phagocytizing sub-mu titanium particles by allergy DNA chip (Genopal (TM)) Peer-reviewed

    Masayuki Taira, Takashi Nezu, Minoru Sasaki, Shigenobu Kimura, Tadayoshi Kagiya, Hidemitsu Harada, Takayuki Narushima, Yoshima Araki

    BIO-MEDICAL MATERIALS AND ENGINEERING 19 (1) 63-70 2009

    Publisher: IOS PRESS

    DOI: 10.3233/BME-2009-0564  

    ISSN:0959-2989

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    The purpose of this study was to examine gene expressions of macrophage phagocytizing sub-mu Ti particles by a DNA chip. Human monocytic cell line THP-1 was differentiated into macrophages by culturing for two days in medium supplemented with 200 nM phorbol ester (PMA). The macrophages were then cultured in four media: medium without PMA (control); medium with suspended sub-mu Ti particles (0.5 wt%); medium with 1.0 mu g/ml lipopolysaccharide (LPS); and medium with LPS and Ti particles. After 6 hours&apos; culture, total RNA were extracted and gene expressions were evaluated by DNA allergy chip with 205 allergy and inflammation related gene spots. We found that phagocytosis of sub-mu Ti particles and LPS independently and synergistically up-regulated 17 inflammation-related genes more than two-fold. The extensive expressions of four genes (CCL1, IL1B, IL6 and IL8) were further confirmed by real-time quantitative PCR. It turned out that dual stimulation of LPS and Ti particles most up-regulated three genes (IL1B, IL6 and IL8), followed by LPS while Ti particles moderately but least increased, suggesting that phagocytosis of sub-mu Ti particles induces moderate inflammation with its degree less than LPS, but phagocytosis of sub-mu Ti particles has the potential to worsen inflammation caused by LPS-stimulated macrophages.

  143. Calcium phosphate films with/without heat treatments fabricated using RF magnetron sputtering Peer-reviewed

    Kyosuke Ueda, Yuuki Kawasaki, Takayuki Narushima, Takashi Goto, Jun Kurihara, Hironobu Nakagawa, Hiroshi Kawamura, Masayuki Taira

    Journal of Biomechanical Science and Engineering 4 (3) 392-403 2009

    DOI: 10.1299/jbse.4.392  

    ISSN:1880-9863

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    Calcium phosphate coating films were fabricated on blast-treated titanium plates and screw-type titanium implants using RF magnetron sputtering. A uniform and dense coating film with a thickness of 0.5 μm could cover the blast-treated titanium plate efficiently, maintaining the surface roughness of the substrates. The as-sputtered coating films consisted of amorphous calcium phosphate (ACP) or oxyapatite (Ca10(PO4)6O, OAp). Heat treatments of the OAp coating films were conducted in a silica ampoule or in air, and it was observed that the crystallinity of the coating films increased after the heat treatment. The bonding strength between the as-sputtered coating films, subjected to heat treatment in air, and the blast-treated titanium plates exceeded 60 MPa. An immersion test was conducted and alkaline phosphatase (ALP) activity of osteoblasts was investigated in vitro. The dissolution rate of the coating films in the 0.9% NaCl solution decreased with an increase in their crystallinity. The ACP coating film exhibited high ALP activity. As the in vivo evaluation, the coated and non-coated titanium implants were implanted into the femur of Japanese white rabbits. The percentage of bone-implant contact and the removal torque value of the coated titanium implants were greater than those of the non-coated titanium implants.

  144. チタンのユビキタス化戦略 Peer-reviewed

    新家光雄, 塙 隆夫, 池田勝彦, 千葉昌彦, 古原 忠, 成島尚之, 土谷浩一, 江村 聡, 中野貴由, 竹中俊英

    2008/12

  145. Fabrication of Titanium Single Crystal by a Floating Zone Method under Extremely Low Oxygen Partial Pressure Peer-reviewed

    Koji Hagihara, Takahiro Tachibana, Keita Sasaki, Yoshiyuki Yoshida, Naoki Shirakawa, Tohru Nagasawa, Takayuki Narushima, Takayoshi Nakano

    JOURNAL OF THE JAPAN INSTITUTE OF METALS 72 (12) 928-934 2008/12

    Publisher: JAPAN INST METALS

    DOI: 10.2320/jinstmet.72.928  

    ISSN:0021-4876

    eISSN:1880-6880

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    In this study, we focused on the fabrication of titanium single crystal by the floating zone melting process under the Ar gas flow atmosphere where partial pressure of oxygen was kept to be extremely low around P-O2 = 10(-23) atm, by using the newly developed oxygen reduction system. In the obtained single crystal, distribution of solute oxygen atoms exhibited a peculiar gradient. In the portion gained in an early stage of the crystal growth the oxygen content showed a higher value of about 1600 ppm than that in the mother ingot of 980 ppm. As the crystal growth proceeded, however, the oxygen content showed a gradual decrease, and in the final portion of the crystal growth, the oxygen content dropped down to 660 ppm. Such a gradient of oxygen composition was not detected in Ti single crystals fabricated under the standard and usual Ar gas flow condition. Owing to the unique gradient of oxygen content under extremely low oxygen partial pressure; the Vickers hardness in the single crystal showed a gradual decrease along the crystal growth direction.

  146. Surface Hardening Method for Titanium Materials Using Ar-5%CO Gas in Combination with Post Heat Treatment under Vacuum Peer-reviewed

    Y. Z. Kim, Takashi Konno, Taichi Murakami, Takayuki Narushima, Chiaki Ouchi

    JOURNAL OF THE JAPAN INSTITUTE OF METALS 72 (12) 1002-1009 2008/12

    Publisher: JAPAN INST METALS

    DOI: 10.2320/jinstmet.72.1002  

    ISSN:0021-4876

    eISSN:1880-6880

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    Surface hardening using solute oxygen formed by dissociation of oxidation film on C.P. (commercially pure) titanium, alpha+beta type Ti-4.5Al-3V-2Fe-2Mo (SP-700) alloy and beta type Ti-15Mo-5Zr-3Al (Ti-15-53) alloy was investigated. This method consists of two processes at 1073 K; surface hardening in use of Ar-5%CO gas with a short period of time and subsequent heat treatment under vacuum. The maximum surface hardness and hardening layer depth of C.P. titanium obtained by surface hardening for 1.8 ks were 420 Hv and 30 pm, respectively and these values increased to 820 Hv and 70 mu m, respectively, by post heat treatment for 14.4 ks. The extra-surface hardening obtained by post heat treatment was yielded by solid solution hardening of oxygen with the following steps; the solute oxygen is continuously formed at oxide/titanium interface by the dissociation of oxidation film formed by the surface hardening treatment, and then it diffuses into titanium matrix. The maximum surface hardness was the highest in C.P. titanium and the lowest in Ti-15-53. On the other hand, the hardening layer depth was the deepest in Ti-15-53 and the shallowest in C.P. titanium. These results could be explained by the difference of solubility and diffusivity of solute oxygen between titanium alpha and beta phases. This two-step process seems to be a beneficial industrial surface hardening method for titanium materials because it enables to remove the oxide film, achieving the very high maximum surface hardness comparable to that obtained by one-step surface hardening under the same total processing time.

  147. Hydroxyapatite formation on Ca-P-O coating prepared by MOCVD Peer-reviewed

    Mitsutaka Sato, Rong Tu, Takashi Goto, Kyosuke Ueda, Takayuki Narushima

    MATERIALS TRANSACTIONS 49 (8) 1848-1852 2008/08

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MRA2008097  

    ISSN:1345-9678

    eISSN:1347-5320

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    Ca-P-O coatings of alpha-tricalcium phosphate (alpha-TCP) and hydroxyapatite (HAp) films were prepared on commercially pure Ti (CP-Ti) by MOCVD using Ca(dpm)(2) and (C6H5O)(3)PO precursors. The behavior of apatite formation on the Ca-P-O coatings was investigated by immersing specimens in a Hanks' solution. An apatite phase has regenerated on the alpha-TCP coating after 1 day and has covered the whole specimen surface after 14d. On the HAp coating. an apatite phase has regenerated after 1 h and has covered the whole surface after 6h. The microstructure of the regenerated apatite phase on the HAp coating has changed from a needle-like to a network texture after 12h.

  148. In Vivo Evaluation of Bioresorbable Calcium Phosphate Films Coated on Titanium Implant by RF Magnetron Sputtering Peer-reviewed

    H.Nakagawa, T.Katsube, K.Ueda, J.Kurihara, T.Goto, T.Narushim, H.Kawamura

    Japanese Journal of Maxillo Facial Implants 7 (1) 3-13 2008/06/25

  149. Fabrication and evaluation of calcium phosphate coating films on blast-treated Ti-6Al-4V alloy substrate Peer-reviewed

    Takayuki Narushima, Kyosuke Ueda, Takashi Goto, Tomoyuki Katsube, Hiroshi Kawamura, Hironobu Nakagawa, Masayuki Taira

    Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 55 (5) 318-324 2008/05

    DOI: 10.2497/jjspm.55.318  

    ISSN:0532-8799

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    Calcium phosphate coating films were fabricated on Ti-6Al-4V alloy plates and implants with a blast-treated surface using radiofrequency (RF) magnetron sputtering and were evaluated in vitro and in vivo. Amorphous calcium phosphate (ACP) and oxyapatite (OAp) films obtained in this study could cover the blast-treated Ti-6Al-4V substrate very efficiently, maintaining the surface roughness. For the in vitro evaluations of the calcium phosphate coating films, bonding strength and alkaline phosphatase (ALP) activity were examined. The bonding strength of the coating films to a blast-treated Ti-6Al-4V plate exceeded 60 MPa, independent of film phases. When compared with an uncoated Ti-6Al-4V plate, the increase in the ALP activity of osteoblastic SaOS-2 cells on a blast-treated Ti-6Al-4V plate coated with the ACP and OAp films was confirmed by a cell culture test. The removal torque of screw type Ti-6Al-4V implants with a blast-treated surface from the femur of a Japanese white rabbit increased with the duration of implantation and it was statistically improved by coating an ACP film two weeks after implantation. The in vitro and vivo studies suggested that the application of the sputtered ACP film as a coating on titanium implants was effective in improving their biocompatibility with the bones.

  150. Preparation of Ca-Ti-O/Ca-P-O functionally graded bio-ceramic film by MOCVD Peer-reviewed

    Mitsutaka Sato, Rong Tu, Takashi Goto, Kyosuke Ueda, Takayuki Narushima

    Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 55 (5) 325-330 2008/05

    DOI: 10.2497/jjspm.55.325  

    ISSN:0532-8799

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    Ca-Ti-O and Ca-P-O films were prepared by MOCVD. The phases, composition and morphology of Ca-Ti-O and Ca-P-O films changed depending on the molar ratio of Ca to Ti (RCa/Ti) and Ca to P (RCa/P) precursors, total pressure (Ptot) and substrate temperature (Tsub). CaTiO3 films in a single phase were obtained at Tsub=973 and 1073 K. CaTiO3 films prepared at Tsub= 873 K had a dense and smooth surface. CaTiO3 films prepared at Tsub= 1073 K had complicated rough surface with a cauliflower-like texture. α-TCP and HAp films in a single phase were obtained at Tsub, = 973 and 1073 K, and both films had dense microstructure. Apatite formed after 3 days on the CaTiO3 film, while 14 days on the a-TCP film and 6 hours on the HAp film, respectively. Functionally graded Ca-Ti-O/Ca-P-O films were successfully prepared by MOCVD, and expected to have good bone conductivity and adherence to Ti substrate.

  151. The effect of solute elements on hardness and grain size in platinum based binary alloys Peer-reviewed

    Taichi Murakami, Ryoji Sahara, Daisuke Harako, Masahiro Akiba, Takayuki Narushirna, Chiaki Ouchi

    MATERIALS TRANSACTIONS 49 (3) 538-547 2008/03

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MRA2007265  

    ISSN:1345-9678

    eISSN:1347-5320

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    The effects of 25 kinds of solute elements on hardness and grain size in annealed Pt-based binary alloys were investigated together with cold workability and a hardness variation with a cold rolling reduction. Gain size largely varied depending on solute elements and their concentrations, and so the decrement in grain size per I at% solute addition was evaluated based on grain size difference between pure platinum and a respective alloy. This value markedly reduced in the low solute concentration range below 5 at%, followed by a sluggish reduction in the higher solute concentration range. Hardness values obtained in all alloys were corrected considering contribution of hardening due to grain refinement, and solid solution hardening was evaluated by the increment in hardness per I at% solute addition. The lattice constants of pure platinum and alloys were measured to calculate the size misfits. The increment in hardness increased with the increase in the size misfit in all alloys, and this relationship was clearly divided into two groups depending on whether the binary alloy system is a completely miscible type or a type with the solubility limit. The increment in hardness in the latter type of alloys was much higher than that of the former, and this value became larger with the increase in the inverse value of the solubility limit in Pt-based binary alloy. The superior cold workability and very similar work hardening behavior were observed in all Pt-based binary alloys.

  152. Deoxidation of NiTi alloy melts using metallic barium Peer-reviewed

    Susumu Miyamoto, Masatoshi Watanabe, Takayuki Narushima, Yasutaka Iguchi

    MATERIALS TRANSACTIONS 49 (2) 289-293 2008/02

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MRA2007219  

    ISSN:1345-9678

    eISSN:1347-5320

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    The deoxidation behavior of NiTi alloy melts with metallic barium was investigated. Metallic barium was added to the NiTi alloy melts held in lime (CaO) crucibles at 1673 K, and the concentrations of oxygen, barium and calcium in the melts were quantitatively measured. The oxygen content in a raw NiTi alloy bar was 660 ppm, and the oxygen content in the NiTi alloy melts just before barium addition was around 1100 ppm. Oxygen was introduced into the melts by the dissolution of lime during melting. The addition of barium lowered the oxygen content in the melts with the formation of deoxidation product, which might be barium oxide. The oxygen content was measured to be around 350 ppm 120 s after barium addition. The barium and calcium contents were less than 10 ppm and 12 ppm, respectively, indicating that the deoxidation product was removed from the melts in a very short period of time. These results suggest that barium is an effective deoxidation element for NiTi alloy melts. Furthermore, the interaction between oxygen and barium cannot be ignored in thermodynamic considerations of the deoxidation process.

  153. Evaluation of sliding wear resistant property of CP titanium and SP-700 titanium alloy surface-hardened by Ar-5%CO gas Peer-reviewed

    Y. Z. Kim, Taichi Murakami, Takayuki Narushima, Chialki Ouch

    ISIJ INTERNATIONAL 48 (1) 89-98 2008

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.48.89  

    ISSN:0915-1559

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    Sliding wear resistant properties of C.P. titanium and SP-700 alloy surface-hardened by Ar-5%CO gas were evaluated using a counterpart material of a bearing steel, JIS SUJ-2 steel and Nishihara type of sliding wear testing machine. In the latter, two disk specimens were rotated at different rotating speeds under a given compressive applied load, yielding a sliding ratio of 20 %. Wear tests were repeated intermittently for several times, and a respective test time period in each series of wear tests was primarily varied. The mass loss in both disks was measured after each test. Wear resistance of annealed C.P. titanium without surface hardening was inferior to that of annealed SUJ-2 steel, but surface hardened C.P. titanium resulted in superior wear resistance over quench-tempered SUJ-2 steel with a hardness of 720 in Hv. Observation results of worn surfaces in both disks indicate that preferential wear occurred in the convex region of a furrow-like pattern formed by a lathe machining, resulting in a reduction of surface roughness values with wear progress. When a respective test time period was extended to 21.6 ks, adhesive wear took place between worn surfaces in both specimens, and the mass loss ratio in titanium disk increased at a much higher rate compared with that of a respective test time period of less than 14.4 ks. The steel debris torn off from worn surface of SUJ-2 steel disk was observed to adhere to the worn surface in surface hardened C.P. titanium disk. Wear resistant property of surface hardened SP-700 alloy was also superior to quench-tempered SUJ-2 steel.

  154. New Manufacturing Method of Iron Foam using Precursor Made of Iron, Graphite and Hematite Powders Peer-reviewed

    T. Murakami, K. Ohara, T. Narushima, C. Ouchi

    POROUS METALS AND METALLIC FOAMS: METFOAM 2007 145-+ 2008

    Publisher: DESTECH PUBLICATIONS, INC

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    Iron based metal foam has several advantages over aluminum alloy foam such as high strength, high energy absorbability and low cost. However, it is hard to manufacture iron foam using conventional foaming agents because of a significant difference between their decomposition temperatures and melting point of iron. In this study, a new manufacturing method of iron foam in use of CO and CO2 gases as foaming agents was studied, which was generated by reduction of iron oxide by carbon contained in iron melt. In this method, the cold-pressed precursor made of pure iron, graphite and hematite powders is heated at temperatures between solidus and liquidus in Fe-C binary system. The powder size and the amount of hematite used to make a precursor markedly affected the porosity and pore size of iron foam. Iron foam with the porosity of approximately 55% was obtained using the precursor with the composition of Fe-3.1%C-1.0%FezO(3).

  155. Austenitic Grain Growth behavior Immediately after Dynamic Recrystallization in HSLA Steels and Austenitic Stainless Steel Peer-reviewed

    Noriki Fujita, Ryoji Sahara, Takayuki Narushima, Chiaki Ouchi

    ISIJ INTERNATIONAL 48 (10) 1419-1428 2008

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.48.1419  

    ISSN:0915-1559

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    Austenitic grain growth behavior after dynamic recrystallization in HSLA steels and the austenitic stainless steel of Type 316L was investigated focusing on grain growth during a very short holding time period immediately after hot deformation. Hot compressed specimens were isothermally held at temperatures of 1373 K, 1 423 K and 1473 K for various time periods from 0.1 s to 1.8 ks. The grain size in all steels was coarsened by 1.5 to 2.5 times in a short holding time period of 20 s. Addition of 0.078%Zr or 0.018%Ti in HSLA steel could not prevent this rapid grain growth, which retarded grain growth in a longer holding time period over 60 s. The grain growth exponent of the n value was evaluated using a formulated grain growth kinetic equation, and two n values largely differing in the fine and coarse grain size regions were obtained in a respective temperature and alloy. The n value in the latter region ranged from 2.3 to 3.2, being almost consistent with values of various materials reported in the past studies. The very high n value over 77 was obtained in the fine grain size region for dynamic recrystallization in all steels, where n values for static recrystallization was relatively lower than those for dynamic recrystallization. The similar result of n values was obtained from grain growth data after dynamic recrystallization in pure nickel. The cause for very high n value and the difference of n values obtained from grain growth data after dynamic and static recrystallizations were discussed based on features of the microstructure and the grain boundary evolved by dynamic or static recrystallization and annealing.

  156. Fatigue Properties of Titanium Wires for Medical Applications Peer-reviewed

    T.Narushima K.Ueda, T.Kinami, H.Kimura, C.Ouchi Y.Iguchi

    Ti-2007, Science and Technology, Proc. the 11th World Conference on Titanium (JIMIC-5) 1505-1508 2007/12/20

  157. In vivo and in vitro Evaluations of Calcium Phosphate Films Coated on Titanium by RF Magnetron Sputtering Peer-reviewed

    K.Ueda T.Narushima T.Goto, H.Nakagawa, H.Kawamura, T.Katsube

    Ti-2007, Science and Technology, Proc. the 11th World Conference on Titanium (JIMIC-5) 1477-1480 2007/12/20

  158. Effect of Alloying Elements on Hot Deformation of Duplex Titanium Alloys Peer-reviewed

    Behrang Poorganji Taichi, Murakami Takayuki, Narushima Chiaki Ouchi, Tadashi Furuhara

    Ti-2007, Science and Technology, Proc. the 11th World Conference on Titanium (JIMIC-5) 535-538 2007/12/20

  159. Evaluation of amorphous calcium phosphate coating films fabricated on titanium by RF magnetron sputtering Peer-reviewed

    K. Ueda, T. Narushima, T. Goto, H. Nakagawa, H. Kawamura, T. Katsube

    1st Asian Biomaterials Congress, Abstract 47 2007/12

  160. Development of a new method for manufacturing iron foam using gases generated by reduction of iron oxide Peer-reviewed

    Taichi Murakami, Kensuke Ohara, Takayuki Narushima, Chiaki Ouchi

    MATERIALS TRANSACTIONS 48 (11) 2937-2944 2007/11

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MRA2007127  

    ISSN:1345-9678

    eISSN:1347-5320

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    A new method for manufacturing iron foam using CO and CO2 as foaming gases was studied. This method consists of three stages: (1) mixing powders of pure iron, graphite, and hematite; (2) preparing the precursor by cold pressing the mixed powders; and (3) foaming by heating the precursor at temperatures between the liquidus and solidus in the Fe-C binary system. Molten iron containing carbon is foamed by gases generated by a reduction reaction. Optimizations of both the composition of the precursor and the heating conditions are required to produce the iron foam with high porosity. It was found that the content and powder size of hematite in the precursor significantly affect the porosity and pore diameter of the iron foam. Iron foam with a porosity of 55% and average pore diameter of around 500 mu m is obtained by heating the precursor of Fe-3.1 mass%C-1.0 mass%Fe2O3 at 1543 K.

  161. Dynamic and static restoration behaviors of pure lead and tin in the ambient temperature range Peer-reviewed

    Satoshi Hotta, Keigo Matsumoto, Taichi Murakami, Takayuki Narushima, Chiaki Ouchi

    MATERIALS TRANSACTIONS 48 (10) 2665-2673 2007/10

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MRA2007078  

    ISSN:1345-9678

    eISSN:1347-5320

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    Dynamic and static restoration behaviors of pure lead and tin were investigated by compression tests, and the deformation temperature and strain rate were varied in the range from 223 to 348 K and from 2 x 10(-3) to 1 s(-1), respectively. Lead and tin used had two purity levels of 99.999% (5N) and 99.9% (3N), and 5N and 4N, respectively. The hot working simulator was reformed so as to enable compression tests at low temperatures ranged from 223 to 273 K. S-S curves observed in lead and tin were those in dynamic recrystallization and dynamic recovery types of metals, respectively, of which activation energies were 92 to 119 kJ/mol in lead and 49 to 52 kJ/mol in tin. Steady state flow stress in lead with 5N purity was lower than that of tin with 5N purity. A reduction of purity level from 5N to 3N in lead significantly increased flow stress, but difference in purity level of 5N and 4N in tin exerted tiny influence on flow stress at strain rate below 1 x 10(-1) s(-1). Static recrystallization in lead with 5N purity completed in the holding time of less than 600 s even at 273 K, while tin with the same purity showed a slightly retarded recrystallization progress. A reduction of purity level in both metals extended the time period for completion of recrystallization by more than 2 orders.

  162. Fabrication of calcium phosphate films for coating on titanium substrates heated up to 773 K by RF magnetron sputtering and their evaluations Peer-reviewed

    Kyosuke Ueda, Takayuki Narushima, Takashi Goto, Masayuki Taira, Tomoyuki Katsube

    Biomedical Materials 2 (3) S160-S166 2007/09/01

    DOI: 10.1088/1748-6041/2/3/S14  

    ISSN:1748-6041 1748-605X

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    Calcium phosphate films were fabricated on titanium substrates heated up to 773 K using radiofrequency (RF) magnetron sputtering. The deposition rate, phase and preferred orientation of the calcium phosphate films were studied. Immersion tests for the films were conducted using Hanks' solution and PBS(-), and the surface reactions on the specimens coated with the calcium phosphate films were investigated. The bonding strength between the coating films and the titanium substrates before and after the immersion tests was evaluated the bonding strength decreased after the immersion tests. The alkaline phosphatase (ALP) activity of SaOS-2 cells on a titanium plate coated with a calcium phosphate film was examined by conducting a culture test. Calcium phosphate coating increased the ALP activity of SaOS-2 cells cultured for 3 and 7 days. Titanium cylinders were coated with an amorphous calcium phosphate film and implanted into the mandibles of beagle dogs. An increase in the extent of bone-implant contact for the coated titanium cylinders was confirmed 8 to 12 weeks after implantation and compared with the case for uncoated titanium cylinders. © 2007 IOP Publishing Ltd.

  163. Hydroxyapatite formation on CaTiO3 film prepared by metal-organic chemical vapor deposition Peer-reviewed

    Mitsutaka Sato, Rong Tu, Takashi Goto, Kyosuke Ueda, Takayuki Narushima

    MATERIALS TRANSACTIONS 48 (6) 1505-1510 2007/06

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MRA2007016  

    ISSN:1345-9678

    eISSN:1347-5320

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    Calcium titanate (CaTiO3) films were prepared on commercially pure titanium (CP-Ti) by metal-organic chemical vapor deposition using Ca(dpm)(2) and Ti(O-i-Pr)(2)(dpm)(2) precursors. The formation of hydroxyapatite (HAp, Ca-10(PO4)(6)(OH)(2)) on CaTiO3 film was investigated in a Hanks' solution. The formation rate of HAp was significantly affected by deposition conditions of CaTiO3 films, particularly substrate temperature (T-sub). The time for the HAp formation was 3.6 Ms (42 d) on the CaTiO3 film prepared at T-sub = 873 K, wheras that was 1.2 (14 d) and 0.3 Ms (3 d) on that prepared at T-sub = 973 and 1073 K, respectively. Octacalcium phosphate (OCP, Ca8H2(PO4)(6).5H(2)O) was identified oil the CaTiO3 film prepared at T-sub = 1073 K by the immersion for 21.6 ks.

  164. The Effect of Small Amounts of Yttrium Addition on Grain Grwoth Under Superplastic Deformation Condition in Newly Developed α+β Type, Ti-4.5Al-6Nb-2Mo-2Fe Alloy Peer-reviewed

    B. Poorganji, S. Hotta, T. Murakami, T. Narushima, Y. Iguchi, C. Ouchi

    Advanced Materials Research 15-17 726-731 2007/04

  165. Evaluation of calcium phosphate coating films on titanium fabricated using RF magnetron sputtering Peer-reviewed

    Kyosuke Ueda, Takayuki Narushima, Takashi Goto, Tomoyuki Katsube, Hironobu Nakagawa, Hiroshi Kawamura, Masayuki Taira

    MATERIALS TRANSACTIONS 48 (3) 307-312 2007/03

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.48.307  

    ISSN:1345-9678

    eISSN:1347-5320

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    Calcium phosphate coating films fabricated on commercially pure titanium (CP-Ti) substrates using radiofrequency (RF) magnetron sputtering were evaluated in vivo and in vitro for investigating their applications in dental and medical implants. For the in vitro evaluations of the calcium phosphate coating films, the bonding strength and alkaline phosphatase (ALP) activity were examined. The bonding strength of the coating films to a polished titanium plate exceeded 60 MPa. When compared with an uncoated titanium plate, the increase in the ALP activity of SaOS-2 cells (a well-characterized osteosarcoma human cell line exhibiting osteoblast-like properties) on a titanium plate coated with a calcium phosphate film was confirmed by a culture test. Titanium cylinders coated with an amorphous calcium phosphate film were implanted into the mandibles of beagle dogs. The percentage of bone-implant contact in coated titanium was greater than that in uncoated titanium.

  166. Calcium phosphate films coated on titanium by RF magnetron sputtering for medical applications Peer-reviewed

    T. Narushima, K. Ueda, T. Goto, T. Katsube, H. Kawamura, C. Ouchi, Y. Iguchi

    THERMEC 2006, PTS 1-5 539-543 551-+ 2007

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/MSF.539-543.551  

    ISSN:0255-5476

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    Calcium phosphate films were coated on commercially pure titanium substrates by radiofrequency magnetron sputtering using beta-tricalcium phosphate targets. The films consisted of amorphous calcium phosphate and oxyapatite phases. Immersion tests of the films were carried out in Hanks' solution and PBS(-), and apatite fort-nation and calcium ion elution from the films were investigated. The titanium cylinders coated with calcium phosphate films were implanted into the mandibles of beagle dogs. These results suggest that coating with calcium phosphate improves the biocompatibility of titanium implants with bone tissue.

  167. EFFECTS OF COOLING RATE AND DIRECT HOT DEFORMATION CONDITIONS AFTER SOLIDIFICATION ON THE AUSTENITIC MICROSTRUCTURE EVOLVED BY SIMULATED STRIP CASTING AND THIN SLAB CASTING PROCESSES IN HSLA STEELS Peer-reviewed

    S. Hotta, T. Murakami, T. Narushima, Y. Iguchi, C. Ouchi

    THERMEC 2006 SUPPLEMENT 15-17 726-731 2007

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/AMR.15-17.726  

    ISSN:1022-6680

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    Currently new continuous casting processes such as thin slab caster or strip casting are industrialized or under developing in the world steel makers. In these casting processes, cooling rate after solidification becomes much faster compared with thick slab caster, and hot rolling mill connected directly with casting machine tends to be installed. The present study was conducted to investigate variations of austenitic grain size and micro segregation with cooling rate after solidification and also direct hot deformation conditions in austenite immediately after solidification in HSLA steels. HSLA steels were 0.15%C-0.25%Si-1.50%Mn, 0.028%Nb and 0.028%Nb-0.015%Ti with the same basic compositions. A hot working simulator of THERMECMASTER-Z was used, and the center part of tensile specimen set up in this machine was partially or fully levitation-melted by induction heating under argon gas atmosphere. After melting, specimens were cooled at cooling rate from 0.4K/s to 40K/s, and this range covered cooling rates after solidification in heavy thick slab caster and strip casting. Direct hot tensile straining in austenite after solidification was conducted at strain rates from 1.4x10(-3) s(-1) to 2.6s(-1), corresponding to an extracting speed in a respective caster. The increase of cooling rate refined continuously as cast austenitic grain size, and it was enhanced in micro alloyed steels. Micro segregation such as Mn was improved by faster cooling. Direct straining after solidification markedly refined austenitic grain size through dynamic or static recrystallization occurring depending on strain rate.

  168. THE EFFECT OF SMALL AMOUNTS OF YTTRIUM ADDITION ON STATIC AND UNDER SUPERPLASTIC DEFORMATION GRAIN GROWTH IN NEWLY DEVELOPED alpha plus beta TYPE, Ti-4.5Al-6Nb-2Mo-2Fe ALLOY Peer-reviewed

    B. Poorganji, S. Hotta, T. Murakami, T. Narushima, Y. Iguchi, C. Ouchi

    THERMEC 2006 SUPPLEMENT 15-17 970-975 2007

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/AMR.15-17.970  

    ISSN:1022-6680

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    New alpha+beta type titanium alloy with Ti-4.5Al-6Nb-2Mo-2Fe was developed on the basis of using biocompatible elements and eliminating the cytotoxic ones such as Vanadium, while achieving the desirable mechanical properties such as appropriate strength, cold workability and low superplastic forming (SPF) temperature. The present study was conducted to investigate the effect of yttrium addition of less than 0.05% into this alloy on static and under superplastic deformation grain growth behavior. The new alloy bar manufactured by alpha+beta processing and annealed at 1073K yielded extremely fine two-phase microstructure with alpha grain size around 2 mu m. Specimens were heated at temperatures of 1048, 1073 and 1098K and kept for times between 3.6 to 172.8KS. Yttrium forms in-situ Y2O3 particles, and the presence of these particles yield finer two phase microstructure due to their retardation effect on beta phase grain growth. Grain growth behavior during hot deformation was investigated by hot compression test in use of a hot working simulator of THERMEC-Master Z. Strain rate was varied from 2x10(-2) to 2x10(-4)S(-1) and strain was 0.69. Grain size of both a and beta phases increased with a reduction of strain rate, and Y2O3 particle was also effective to retard grain growth under hot deformation. It was confirmed from comparison of grain growth during isothermal heating with and without hot deformation that grain growth was much accelerated by deformation. All of these results were discussed based on grain growth mechanism or model for two-phase microstructures as well as superplastic deformation mechanism.

  169. Alloy design and properties of new alpha+beta titanium alloy with excellent cold workability, superplasticity and cytocompatibility Peer-reviewed

    Takahiro Hirano, Taichi Murakami, Masayuki Taira, Takayuki Narushima, Chiaki Ouchi

    ISIJ INTERNATIONAL 47 (5) 745-752 2007

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.47.745  

    ISSN:0915-1559

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    Alloy designing and evaluation of various properties of new alpha+beta type titanium alloy with excellent cold workability, superplasticity, and cytocompatibility were conducted. Alloy designing was performed by investigations of the effects of 0, Al, Mo, Fe, and Nb contents on cold workability of the alloy with a basic composition of Ti-4.5%Al-4.5%Nb-2%Fe-2%Mo. Use of beta stabilizing elements such as V, Ni, or Cu was avoided for biocompatibility. Cold workability was evaluated on the basis of a critical rolling reduction for onset of cracking, hardness under as solution treated condition and hardness variations with a cold rolling reduction, Excellent cold workability was obtained by enhanced thermal and mechanical stabilities of beta phase and by lowered hardness of a phase in the alpha+beta two-phase microstructure. Newly developed alloy Ti-4.5%Al-6%Nb-2%Fe-2Mo showed the beta transus of 1 156 K, a critical rolling reduction over 60 %, and yield strength in recrystallization annealing of 910 MPa. An extremely fine alpha+beta two-phase microstructure with a grain size of approximately 1 pm was evolved by annealing at 1 048 to 1 073 K, and a superplastic elongation value of around 3 000 % was obtained by tensile testing at these temperatures. New alloy showed an excellent cytocompatiblity in a cell culture test using L929 cells, yielding a higher value of cell viability over Ti-6%Al-4%V and Ti-6%Al-7%Nb alloys.

  170. Variations in the microstructure and hardness with solution treating and aging conditions in new alpha+beta Titaniurn alloy Ti-4.5%Al-6%Nb-2%Fe-2%Mo Peer-reviewed

    Takahiro Hirano, Taichi Murakami, Takayuki Narushima, Chiaki Ouchi

    ISIJ INTERNATIONAL 47 (7) 1042-1049 2007

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.47.1042  

    ISSN:0915-1559

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    Variations in the microstructure and hardness with solution treating and aging conditions in new alpha+beta titanium alloy T1-4.5%Al-6%Nb-2%Fe-2%Mo were investigated, Solution treating (ST) temperatures were varied from 1 048 to 1 173 K with both cooling conditions of water quenching and air cooling. Cooling rate after solution treating was varied from 1 to 60 K/s using a hot working simulator. Age-hardening was investigated at temperatures ranged from 573 to 823 K and aging time periods were varied in the range from 0.36 to 32.4 ks. An extremely fine two-phase microstructure with alpha grain size of around 1 mu m was obtained at ST temperature of 1 048 K. The large amount of retained beta phase was obtained by solution treating at temperatures below 1 098 K, and the amounts of alpha martensite and athermal omega phase increased with an elevation of ST temperature above 1 098 K. For solution treating with water quenching, no hardness variation with solution treating temperature was observed. Age-hardening at the temperatures above 723 K took place at an extremely short aging time. Peak-age was observed in such a short aging time period as 0.36 ks, and hardness value at peak-age increased markedly and continuously with an elevation of solution treating temperature. Age-hardening was confirmed to be caused by very fine a precipitates, and age-hardening behavior noted above was explained by athermal omega phase playing a role of a nucleus for a precipitate.

  171. In vitro evaluations of RF magnetron-sputtered calcium phosphate films on titanium Peer-reviewed

    Kyosuke Ueda, Takayuki Narushima, Tomoyuki Katsube, Hiroshi Kawamura, Takashi Goto

    INNOVATION IN CERAMICS SCIENCE AND ENGINEERING 352 305-+ 2007

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/0-87849-454-5.305  

    ISSN:1013-9826

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    Calcium phosphate coating films were fabricated on mirror-polished or blast-treated titanium substrates using radio-frequency (RF) magnetron sputtering and they were evaluated in vitro. Immersion tests for the films were conducted using phosphate-buffered saline (PBS(-)), and apatite formation and the elution of calcium ions from the films were investigated. The bonding strengths between the calcium phosphate films and titanium substrates before and after the immersion tests were evaluated. After the immersion tests, a decrease in the bonding strength was observed for the coating films on the mirror-polished titanium substrates, while that for the blast-treated titanium substrates was almost the same as that before the immersion tests.

  172. Hydroxyapatite formation on MOCVD-CaTiO3 coated Ti Peer-reviewed

    Mitsutaka Sato, Rong Tu, Takashi Goto, Kyosuke Ueda, Takayuki Narushima

    INNOVATION IN CERAMICS SCIENCE AND ENGINEERING 352 301-+ 2007

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/0-87849-454-5.301  

    ISSN:1013-9826

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    Ca-Ti-O films were prepared by MOCVD using Ca(dpm)(2) and Ti(OiPr)(2)(dpm)(2) precursors. The phases, composition and morphology of Ca-Ti-O films changed depending on the molar ratio of Ca to Ti precursors (R-Ca/Ti), total pressure (P-tot) and substrate temperature (T-sub). CaTiO3 films in a single phase were obtained at T-sub = 973 and 1073 K. CaTiO3 films prepared at 873 K had a dense structure and smooth surface. CaTiO3 films prepared at T-sub = 1073 K had complicated rough surface with a cauliflower-like texture. Hydroxyapatite (HAp) formed in 3 days on the CaTiO3 film prepared at T-sub = 1073 K.

  173. Hydroxyapatite formation on calcium phosphate coated titanium Peer-reviewed

    Mitsutaka Sato, Rong Tu, Takashi Goto, Kyosuke Ueda, Takayuki Narushima

    PRICM 6: SIXTH PACIFIC RIM INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS AND PROCESSING, PTS 1-3 561-565 1513-+ 2007

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/MSF.561-565.1513  

    ISSN:0255-5476

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    Calcium phosphate films were prepared by MOCVD using Ca(dpm)(2) and (C6H5O)(3)PO precursors. The phases, composition and morphology of films changed depending on the molar ratio of Ca to P precursors (R-Ca/P), total pressure (P-tot) and substrate temperature (T-sub). alpha-tricalcimu phosphate (alpha-TCP, alpha-Ca-3(PO4)(2)) Films in a single phase were obtained at T-sub = 1073 K, 0.1 &lt; R-Ca/P &lt; 0.4 and T-sub = 973 K, RCa/P &lt; 0.4. Hydroxyapatite (HAp, Ca-10(PO4)(6)(OH)(2)) films in a single phase were obtained at T-sub = 1073 K, 0.8 &lt; R-Ca/P &lt; 1.0 and T-sub = 973 K, 0.5 &lt; R-Ca/P &lt; 0.6. Ca-P-O films had a dense and smooth surface. HAp formed within 1 day on the alpha-TCP film and wholly covered the specimens within 2 weeks in a Hanks' solution. The surface of CVD-HAp film was covered by precipitated HAp within 6 hours.

  174. 口腔内自動骨延長器の開発:ビーグル犬下顎骨への適用 Peer-reviewed

    勝部朝之, 成島尚之, 中野貴由, 馬越佑吉, 佐々木具文, 伊藤秀美, 古屋泰文, 川村仁

    第6回バイオメカニクス論文集 2006/12

  175. Accumulation of element Ti in macrophage-like RAW264 cells cultured in medium with 1 ppm Ti and effects on cell viability, SOD production and TNF-alpha secretion Peer-reviewed

    Masayuki Taira, Kaori Sasaki, Setsuo Saitoh, Takashi Nezu, Minoru Sasaki, Shigenobu Kimura, Kazunori Terasaki, Kouichiro Sera, Takayuki Narushima, Yoshima Araki

    DENTAL MATERIALS JOURNAL 25 (4) 726-732 2006/12

    Publisher: JAPANESE SOC DENTAL MATERIALS DEVICES

    DOI: 10.4012/dmj.25.726  

    ISSN:0287-4547

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    The adverse effect of Ti on body-defense macrophage is not well understood. The aims of this study were twofold: (1) to examine the intracellular accumulation of Ti element; and (2) to measure the cell viability, superoxide dismutase (SOD) production, and TNF-alpha secretion of macrophage-like RAW264 cells cultured for two days in medium with I ppm Ti prepared from acidic ICP Ti standard solution. PIXE analysis showed that element Ti was accumulated up to 7.3 ppm in RAW264 cells when cultured in the medium with 1 ppm Ti. Further, RAW264 cells cultured in the medium with 1 ppm Ti exhibited cell viability of about 60%, SOD production of about 180%, and TNF-alpha secretion of about 170% relative to those of control cells cultured in the medium without Ti. It was speculated that phagocytosis of minute Ti-containing complex (mostly TiO2) by macrophage caused oxidative stress and inflammatory reaction, leading to cell proliferation arrest and increased production of SOD and TNF-alpha.

  176. In Vivo Evaluation of Calcium Phosophate Films on Titanium Implant by RF Magnetron Sputtering Peer-reviewed

    T.Katsube, H.Nakagawa, T.Narushima, H.Kawamura

    Proceedings of XVIII International Congress of the European Association for Cranio-Maxillofacial Surgery 67-72 2006/12

  177. Oxidation or nitridation behavior of pure chromium and chromium alloys containing 10 mass% ni or Fe in atmospheric heating Peer-reviewed

    Kaori Taneichi, Takayuki Narushima, Yasutaka Iguchi, Chiaki Ouchi

    MATERIALS TRANSACTIONS 47 (10) 2540-2546 2006/10

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.47.2540  

    ISSN:1345-9678

    eISSN:1347-5320

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    The oxidation or nitridation behavior of pure chromium and chromium alloys containing 10 mass%Ni or 10 mass%Fe in atmospheric heating was investigated in the temperature range of 1073 to 1373 K. The formation behavior of the outer oxide phase of Cr2O3 and its growth kinetics in both chromium alloys was very similar to that of pure chromium. The nitride layer with the Cr2N phase was formed beneath the oxide phase at temperatures above 1273 K in pure chromium. Marked internal nitridation with the formation of the Cr2N phase was observed in the Cr-10 mass%Fe alloy, while the formation Of Cr2N was negligible in the Cr-10 mass%Ni alloy. Neither Ni nor Fe were detected inside the Cr2O3 phase, and was enriched in the subsurface layer between the oxide layer and the base alloy in a respective alloy. The Ni-enriched layer in Cr-10mass%Ni alloy had a relatively narrow width, but a very high concentration of Ni compared with the Fe-enriched layer formed in the Cr-10mass%Fe alloy.

  178. Preparation of Graded Biocompatible Films by MOCVD Peer-reviewed

    M.Sato, R.Tu, T.Goto, K.Ueda, T.Narushima

    Proc.FGM 20 109-114 2006/10

  179. Surface hardening treatment in use of CO gas and post-heat treatment in C.P. titanium and titanium alloys Peer-reviewed

    Y. Z. Kim, T. Murakami, T. Narushima, Y. Iguchi, C. Ouchi

    Solid State Phenomena 118 109-114 2006

    Publisher: Trans Tech Publications Ltd

    DOI: 10.4028/www.scientific.net/SSP.118.109  

    ISSN:1662-9779

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    Surface hardening treatment of titanium materials in use of CO gas was studied including investigation of post heat treatment under vacuum. C.P. titanium, α+β type SP-700 alloy with Ti-4.5%Al-3%V-2%Mo-2%Fe and β type alloy with Ti-15%Mo-5%Zr-3%Al were used. Surface hardening was conducted by heating these materials at 1073K for 21.6ks in Ar-5%CO gas. Subsequently, specimens subjected to surface hardening were heated at 1073k for various time periods under vacuum. While the maximum surface hardness value was the largest in C.P. titanium and the least in SP-700 alloy, hardening layer thickness was the thickest in β type alloy and the thinnest in C.P. titanium. Surface hardening in C.P. titanium was brought about by solid solution hardening due to oxygen and carbon. Enrichment of these elements in the surface layer of both titanium alloys caused continuous variations of the microstructure such as β to α+β, or their volume fractions in the surface hardening layer. Post heat treatment at 1073K increased the maximum surface hardness and hardening layer thickness with an extension of the heating time in C.P. titanium, but the surface maximum hardness decreased continuously in β type titanium alloy. Post heat treatment could remove the thin oxide layer formed by surface hardening treatment.

  180. beta grain refinement due to small amounts of yttrium addition in alpha plus beta type titanium alloy, SP-700 Peer-reviewed

    S Hotta, K Yamada, T Murakami, T Narushima, Y Iguchi, C Ouchi

    ISIJ INTERNATIONAL 46 (1) 129-137 2006

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.46.129  

    ISSN:0915-1559

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    The effect of small amounts of yttrium addition on refinement of beta grain size and grain growth behavior in SP-700 alloy with Ti-4.5%Al-3%V-2%Fe-2%Mo was investigated in the temperature region from 1 223 to 1 573 K. Yttrium and oxygen contents in yttrium-added alloys were varied from 0.007 to 0.070 % and 0.017 to 0.086 %, respectively. Such a small amount of yttrium addition as 0.007 % resulted in marked beta grain refinement. Variation of beta grain size with the heating temperature exhibited rapid grain growth at the particular temperature, which became higher with the increase of yttrium or oxygen content in alloys. It was confirmed that beta grain refinement and grain growth behavior with the heating temperature in yttrium-added alloys were brought about by fine precipitates of yttria and dissolution of these precipitates into the beta matrix at the higher temperature. TEM and SEM observations of yttrium-added alloys revealed the cubic shape of yttria precipitates with the size of 0.1 to 0.2 mu m, and this range of the precipitate's size was well fitted to results analyzed by modified Zener' model for pinning of grain boundary due to a fine particle. Based on assumption that the onset temperature of rapid grain growth corresponds to the re-dissolution temperature of yttria into the beta phase, solubility product of Y2O3 in reaction of 2Y+3O reversible arrow Y2O3 was obtained in use of data of variation of the onset temperature of rapid grain growth with yttrium and oxygen contents in alloys. It was also confirmed that yttria powder could be used as an alloying additive of yttrium in melting of yttrium-added alloys.

  181. Surface hardening treatment for titanium and titanium alloys in use of CO2 gas Peer-reviewed

    Y-Z. Kim, Ryoji Sahara, Takayuki Narushima, Yasutaka Iguchi, Chiaki Ouchi

    TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN 92 (1) 1-9 2006/01

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/tetsutohagane1955.92.1_1  

    ISSN:0021-1575

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    Surface hardening treatment of C.P. titanium, a + beta type Ti-4.5%Al-3%V-2%Mo-2%Fe (SP-700 alloy) and beta type Ti-15%V-3%Al-3%Cr-3%Sn alloy in use of Ar-20%CO2 gas was studied at temperatures between 973 to 1123K in comparison of Ar-20%O-2 gas. Weight gain of the specimen during heating was measured by all electric balance, and surface oxide layer thickness was also measured. Surface hardening was evaluated by measurement of micro-hardness distribution profile in the surface layer. Surface hardening due to Ar-20%O-2 gas yielded the larger maximum surface hardness value and thicker hardening layer thickness in all three titanium materials compared with Ar-20%O-2 gas. The largest surface hardness value was obtained in C.P. titanium, and beta type titanium alloy resulted in the most thick hardening layer thickness although the surface hardness value was the smallest among three titanium materials. The maximum surface hardness and hardening layer thickness obtained ill use of Ar-20%O-2 gas was larger than these of Ar-20%O-2 gas in C.P. titanium, nevertheless the former gas yielded higher oxidation rate over the latter gas. The oxidation rate was the smallest in SP-700 alloy among three titanium materials in both gases. Surface hardening due to Ar-20%O-2 gas in C.P. titanium was brought about by solid solution hardening due to oxygen and carbon.

  182. Alloy design and property evaluation of new beta type titanium alloy with excellent cold workability and biocompatibility Peer-reviewed

    K Taneichi, M Taira, E Sukedai, T Narushima, Y Iguchi, C Ouchi

    ISIJ INTERNATIONAL 46 (2) 292-301 2006

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.46.292  

    ISSN:0915-1559

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    Alloy designing of new beta type titanium alloy with excellent cold workability and biocompatibility was conducted by using total heat numbers of 38 titanium alloys containing Nb, Fe, Ta or Zr in basic compositions of Ti-10%Mo-2%Fe and Ti-14%Mo. Cold workability was evaluated based on hardness values obtained by solution treating and after cold rolling with a rolling reduction ratio up to 90 % as well as a critical rolling reduction ratio for onset of cracking. Excellent cold workability in beta type titanium alloy was obtained by enhanced thermal and mechanical stability of beta phase through optimum addition of beta stabilizing elements in Ti-14%Mo base alloy and a reduction of beta transus below 1 000 K. Newly developed alloy of T-14%Mo-3%Nb-1.5%Zr yields Vickers hardness values of 240 and 284 in as solution treating and after a cold rolling reduction ratio of 90 %, respectively, and no cracking occurs in rolling reduction ratio up to 90 %. New titanium alloy shows the almost similar level of non-toxicity to other implant titanium materials in the cell culture test using L929 cells, although a slightly increased passive current density is observed by anodic polarization test in both solutions of saline and I mass% lactic acid. New austenitic stainless steel of Fe-6%Mn-22%Cr-10%Ni-2%Mo-0.4%N used as one of comparative materials for evaluation of biocompatibility results in the same level of non-toxicity with new titanium alloy, while relatively poor non-toxicity of the Type 316L steel is observed by cell culture test.

  183. Surface hardening treatment in use of CO gas and post-heat treatment in CP titanium and titanium alloys Peer-reviewed

    Y. Z. Kim, T. Murakami, T. Narushima, Y. Iguchi, C. Ouchi

    HEAT TREATMENT OF MATERIALS 118 109-+ 2006

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/3-908451-25-6.109  

    ISSN:1012-0394

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    Surface hardening treatment of titanium materials in use of CO gas was studied including investigation of post heat treatment under vacuum. C.P. titanium, alpha+beta type SP-700 alloy with Ti-4.5%A1-3%V-2%Mo-2%Fe and beta type alloy with Ti-15%Mo-5%Zr-3%Al were used. Surface hardening was conducted by heating these materials at 1073K for 21.6ks in Ar-5%CO gas. Subsequently, specimens subjected to surface hardening were heated at 1073k for various time periods under vacuum. While the maximum surface hardness value was the largest in C.P. titanium and the least in SP-700 alloy, hardening layer thickness was the thickest in beta type alloy and the thinnest in C.P. titanium. Surface hardening in C.P. titanium was brought about by solid solution hardening due to oxygen and carbon. Enrichment of these elements in the surface layer of both titanium alloys caused continuous variations of the microstructure such as beta to alpha+beta, or their volume fractions in the surface hardening layer. Post heat treatment at 1073K increased the maximum surface hardness and hardening layer thickness with an extension of the heating time in C.P. titanium, but the surface maximum hardness decreased continuously in beta type titanium alloy. Post heat treatment could remove the thin oxide layer formed by surface hardening treatment.

  184. Characterization of calcium phosphate films prepared by RF magnetron sputtering Peer-reviewed

    Takayuki Narushima, Kyosuke Ueda, Takashi Goto, Tomoyuki Katsube, Hiroshi Kawamura, Chiaki Ouchi, Yasutaka Iguchi

    MATERIAL AND DEVICES FOR SMART SYSTEMS II 888 101-+ 2006

    Publisher: MATERIALS RESEARCH SOC

    ISSN:0272-9172

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    Calcium phosphate films were prepared on commercially pure titanium (CP-Ti) substrates by RF magnetron sputtering using beta-tricalcium phosphate targets. XRD and FTIR analyses showed that the films consisted of amorphous calcium phosphate and oxyapatite phases. The (002) preferred orientation of the oxyapatite phase was observed depending on the oxygen gas concentration in the sputtering gas. The surface reactions of the calcium phosphate films were investigated in Hanks' solution and PBS(-). Apatite crystallites were detected on the films after immersion for 7 days. An active surface reaction was observed on the amorphous calcium phosphate films during immersion in PBS(-). The CP-Ti plates coated with the calcium phosphate films were placed on the mandible of male Japanese white rabbits. These results suggest that the calcium phosphate coating improves the biocompatibility of titanium implants with bone.

  185. Surface hardening treatment for CP titanium and titanium alloys in use of Ar-5%CO gas Peer-reviewed

    Y. Z. Kim, T. Murakami, T. Narushima, Y. Iguchi, C. Ouchi

    ISIJ INTERNATIONAL 46 (9) 1329-1338 2006

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.46.1329  

    ISSN:0915-1559

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    Surface hardening of C.P. (commercially pure) titanium and titanium alloys in use of Ar-5%CO gas was investigated in the temperature range between 973 K and 1 123 K. Ttanium materials used were alpha+beta type alloy of Ti-4.5%Al-3%V-2%Mo-2%Fe (SP-700) and beta type alloy of Ti-15%V-3%Cr-3%Sn-3%Al (Ti-15-333). Oxidation accompanied with surface hardening in use of Ar-5%CO gas is much reduced compared with that of Ar-20%CO2 gas. Surface hardening was evaluated by both of the maximum surface hardness and hardening layer depth obtained from hardness distribution profiles in the subsurface region, The former is the highest in C.P. titanium and the lowest in Ti-15-333 alloy, and the latter is the deepest in Ti-15-333 alloy and the shallowest in C.P. titanium. Surface hardening in C.P. titanium is caused by solid solution hardening of oxygen and carbon enriched in the subsurface region. Enrichment of these interstitials in the subsurface region of SP-700 or Ti-15-333 alloys causes the increase of a volume fraction in alpha+beta two phases or phase transformation from beta to alpha+beta two phases, respectively, and surface hardening is primarily controlled by volume fraction of alpha phase hardened by interstitials enrichment. The other beta type titanium alloy of Ti-15%Mo-5%Zr-3%Al yields much marked surface hardening over T-15-333 alloy. All of these results were analyzed and discussed based on oxygen and carbon concentration profiles, which were obtained by EPMA, and were also calculated by uni-dimensional diffusion model.

  186. Surface Hardening treatment in use of CO gas and Post-heat treatment in C.P. Titanium and Titanium Alloys Peer-reviewed

    Y. Z. Kim, T. Murakami, T. Narushima, Y. Iguchi, C. Ouchi

    Proceedings of The 3rd Asian Conference on Heat Treatment of Materials 252-254 2005/11

  187. Preferred Orientation of Calcium Phosphate Films Prepared by RF Magnetron Sputtering Peer-reviewed

    K. Ueda, T. Narushima, T. Goto, T. Katsube, H. Kawamura, C. Ouchi, Y. Iguchi

    Archives of BioCeramics Research 5 59-62 2005/11

  188. Preparation of calcium phosphate films by radiofrequency magnetron sputtering Peer-reviewed

    T Narushima, K Ueda, T Goto, H Masumoto, T Katsube, H Kawamura, C Ouchi, Y Iguchi

    MATERIALS TRANSACTIONS 46 (10) 2246-2252 2005/10

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.46.2246  

    ISSN:1345-9678

    eISSN:1347-5320

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    Calcium phosphate films were prepared on titanium substrates by radiofrequency (RF) magnetron sputtering at RF powers from 75 to 150 W. Hot-pressed beta-tricalcium phosphate (beta-TCP) plates with a high density (&gt; 99.6%) were used as a sputtering target. The substrate was not intentionally heated. The films consisted of amorphous calcium phosphate and oxyapatite (Ca-10(PO4)(6)O) phases, The ratio of the oxyapatite phase depended on the sputtering conditions of RF power. oxygen gas concentration in the sputtering gas (Co-2) and total pressure in the chamber. The (002) preferred orientation of oxyapatite phase was observed. The deposition rate of films increased with increasing RF power and decreasing Co-2. The highest deposition rate was 0.143 nm center dot s(-1) (0.515 mu m center dot h(-1)).

  189. Development of dental and medical systems for reconstruction of human body with high performance titanium materials Peer-reviewed

    Tomoyuki Katsube, Kyosuke Ueda, Takayuki Narushima, Takashi Goto, Yasutaka Iguchi, Hiroshi Kawamura

    International Congress Series 1284 324-325 2005/09

    DOI: 10.1016/j.ics.2005.06.067  

    ISSN:0531-5131

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    Calcium phosphate films on the surface of titanium have been investigated in order to apply them to the device for clinical treatments in oral and maxillofacial fields. The calcium phosphate films were coated on substrates by RF magnetron sputtering method. Commercially pure titanium (CP-Ti) plates were used as substrates. The films consisted of amorphous calcium phosphate and oxyapatite phases. The c-axis, (002), preferred orientation of oxyapatite phase was observed. The histological results demonstrated that the titanium plates coated with the calcium phosphate film were in close contact with bone at some parts of the interfaces between the bone and the implant, compared with non-coated titanium plates. © 2005 Elsevier B.V. All rights reserved.

  190. Fatigue properties of stainless steel wire ropes for electrodes in functional electrical stimulation systems Peer-reviewed

    T Narushima, K Suzuki, T Murakami, C Ouchi, Y Iguchi

    MATERIALS TRANSACTIONS 46 (9) 2083-2088 2005/09

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.46.2083  

    ISSN:1345-9678

    eISSN:1347-5320

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    The fatigue properties of stainless steel wire ropes with 19 strands developed for a functional electrical stimulation (FES) electrode in simulated body fluids were investigated. The wire ropes were made of a new austenite stainless steel (Fe-22Cr-10Ni-6Mn-2Mo-0.4N alloy) and Type 316L stainless steel. Fatigue properties of the wire ropes were evaluated in Hanks' solution and 1 mass% lactic acid solution at 310K using a dual axel-driven rotating-bending fatigue machine. After fatigue testing, the wire ropes were examined by scanning electron microscopy and the metal ion concentrations in the solutions were quantitatively determined. Corrosion products in the solutions were analyzed by transmission electron microscopy. Under low maximum cyclic bending stress level, the Fe-22Cr-10Ni-6Mn-2Mo-0.4N alloy wire rope exhibited a higher cyclic life than the Type 316L stainless steel wire rope. Metal ion concentrations in the lactic acid solution increased with increasing of number of fatigue cycles, and no corrosion products were detected. In Hanks' solution, ferric oxyhydroxides (FeOOH) were formed as corrosion products during fatigue testing and the concentrations of metal ions were lower than those in the lactic acid solution for cyclic tests over 104 cycles.

  191. Materials Transactions: Preface

    Mitsuo Niinomi, Takao Hanawa, Yoshimitsu Okazaki, Masahiko Ikeda, Akihiko Chiba, Takayuki Narushima, Hisao Fukui

    Materials Transactions 46 (7) 1514 2005/07

    ISSN:1345-9678

  192. Effects of dynamic recrystallization on gamma grain refinement and improvement of micro segregation of As cast Austenite in 9% Ni steel Peer-reviewed

    S Hotta, T Murakami, T Narushima, Y Iguchi, C Ouchi

    ISIJ INTERNATIONAL 45 (3) 338-346 2005

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.45.338  

    ISSN:0915-1559

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    Effects of dynamic recrystallization on gamma grain refinement and improvement in micro segregation of elements such as Ni and Mn of as cast austenite in 9 % Ni steel were investigated by two kinds of experimental methods. The first one was a hot compression test using the specimens prepared from the strand cast slab and the hot rolled plate of 9 % Ni steel, and the other was a hot tensile straining test in the austenitic region after levitation melting and solidification. In the hot compression test, variations in onset strain and flow stress of steady state flow of dynamic recrystallization with hot deformation conditions were investigated. The onset strain was found to decrease below 0.25 at the temperatures above 1 523 K and the strain rate below 1 x 10(-2) s(-1). The activation energy value obtained from steady state flow stress was 421 kJ/mol. Dynamically recrystallized gamma grain size in as cast austenite of this steel was controlled simply by Z value with no dependence on the initial gamma grain size. This beneficial feature of dynamic recrystallization was confirmed by the experiment of tensile straining in austenite formed after levitation melting and solidification, where extremely coarse initial gamma grain size of around 1.9 mm was markedly refined down to 140 pm by straining such a small strain as 0.40. Micro segregation ratio of Ni and Mn in the strand cast 9 % Ni steel examined by EPMA analysis was 1.20 and 1.36, respectively. These values were found to decrease continuously with reduction in strain rate in hot deformation of austenite. That is, dynamic recrystallization in austenite taken place at lower strain rate deformation is much more effective for homogenization of segregated elements compared with high strain rate deformation.

  193. Hydrothermal synthesis of zeolite a using blast furnace slag Peer-reviewed

    Y Sugano, R Sahara, T Murakami, T Narushima, Y Iguchi, C Ouchi

    ISIJ INTERNATIONAL 45 (6) 937-945 2005

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.45.937  

    ISSN:0915-1559

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    Alkali hydrothermal synthesis of zeolite A using blast furnace (BF) slag was investigated. The preliminary experiment was conducted in use of synthetic slag consisting of SiO2, Al2O3, and CaO powders, and it was made clear that the most optimum slag compositions to synthesize zeolite A were the molar ratio of Si to Al (Si/Al) of I and reduction of CaO content down to 15 mass%, and that hydrothermal treating conditions were the temperature range from 328 to 358 K, NaOH solution of 1 M (=mol/L) and the ratio of the volume of NaOH solution to total mass of slag (V-sol/W-slag) of 15 (mL/g). It was also found that synthetic slag with such a higher content of CaO as 40% resulted in formation of tobermorite and hydrogarnet. In the experiment using BF slag, zeolite A could be successfully synthesized by optimizing both conditions of the compositions of raw material powders and hydrothermal treatment as noted above, where optimization of the compositions of raw material powders such as Si or Al content were performed by the suitable amount of addition Of SiO2 powder or NaAlO2 powder as a source of Si and Al. The ball milling type reaction vessel containing numerous small SiC balls which was first adopted in this hydrothermal treating study was confirmed to be very effective for acceleration of synthetic reaction rate, shortening markedly the time period needed for fully synthesis of zeolite A. Temperature dependence of heat capacity of zeolite A powder synthesized in use of BF slag was measured after absorption of vapor at the ambient temperature, showing endothermic behavior with the peak at the temperature of around 473 K.

  194. Wear loss and elution of CPTi and titanium alloys in simulated body fluids Peer-reviewed

    K Ueda, T Narushima, C Ouchi, Y Iguchi

    PRICM 5: THE FIFTH PACIFIC RIM INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS AND PROCESSING, PTS 1-5 475-479 2333-2336 2005

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/MSF.475-479.2333  

    ISSN:0255-5476

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    Wear behavior of titanium materials such as C.P.Ti, Ti-6Al-4V and Ti-6Al-7Nb, was studied in simulated body fluids by means of the pin-on-disk type wear testing. The mass loss in wear testing increased with increasing the sliding distance. The alpha+beta type titanium alloys, Ti-6Al-4V and Ti-6Al-7Nb, exhibited higher wear resistance than the C.P.Ti. Average size of the wear debris was 4.5 mu m and 3.7 mu m for C.P.Ti and the alpha+beta type titanium alloys, respectively. The elution of metallic constituents into 1 mass% lactic acid solution was detected after the wear test.

  195. Evaluation of Fatigue Property of Titanium Wires by Rotating-bending Testing in 1mass% Lactic Acid Solution Peer-reviewed

    T. Narushima, K. Ueda, M. Yamashita, T. Murakami, C. Ouchi, Y. Iguchi

    Proc. of International Functional Electrical Stimulation Society 2004 416-418 2004/07

  196. Boron and nitrogen in GaAs and InP melts equilibrated with B2O3 flux Peer-reviewed

    T Yamada, T Kudo, K Tajima, A Otsuka, T Narushima, C Ouchi, Y Iguchi

    MATERIALS TRANSACTIONS 45 (4) 1306-1310 2004/04

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.45.1306  

    ISSN:1345-9678

    eISSN:1347-5320

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    The boron and nitrogen contents of GaAs and InP melts equilibrated with B2O3 flux were examined at 1523 and 1373 K, respectively, using a chemical equilibrium technique. GaAs or InP was melted with B2O3 flux in a silica ampoule with and without a BN crucible. The boron content decreased with increasing nitrogen content in both of the melts equilibrated with B2O3 flux and BN. The solubility product of BN in the melts was expressed as a function of nitrogen content. The relationship between the boron and nitrogen contents of a GaAs melt coexisted with BN agreed well with that in the residue after LEC crystal growth of GaAs. The boron content of the GaAs melt coexisted with silica was much larger than that of the GaAs melt with BN. It was suggested that the reduction of B2O3 by silicon introduced into the melt from silica led the increase of boron content.

  197. Nitridation of Titanium-Tin Alloys during Heating in Air Peer-reviewed

    T. Narushima, K. Suzuki, S. Kimura, Y. Iguchi, C. Ouchi

    Ti-2003, Science and Technology, Vol.IV 2115-2122 2004/04

  198. Refinement of beta Grain Size Due to TiB or Y<SUB>2</SUB>O<SUB>3</SUB> Precipitates in Titanium Alloy Peer-reviewed

    T. Nomura, N. Yamamoto, T. Narushima, Y. Iguchi, C. Ouchi

    Ti-2003, Science and Technology, Vol.II 1235-1242 2004/04

    Publisher: None

  199. Oxidation of boron carbide-silicon carbide composite at 1073 to 1773 K Peer-reviewed

    T Narushima, T Goto, M Maruyama, H Arashi, Y Iguchi

    MATERIALS TRANSACTIONS 44 (3) 401-406 2003/03

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.44.401  

    ISSN:1345-9678

    eISSN:1347-5320

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    The oxidation behavior of B4C-(25-60 mol%)SiC composites prepared by arc-melting was investigated in the temperature range of 1073 to 1773 K using a thermogravimetric technique. Liquid borosilicate, solid SiO2 and carbon were identified as oxidation products by X-ray diffraction and Raman spectroscopy. Mass gain was observed during oxidation at 1073 K, while mass loss due to the vaporization of boron oxide in liquid borosilicate was observed at temperatures of 1273 K and higher. In situ Raman spectra of the surface of B4C-SiC composites indicated that the silica concentration in the liquid borosilicate increased with increasing SiC content in the composite. Micro-Raman spectroscopy showed that carbon was enriched in the borosilicate layer close to the oxide/composite interface. The parabolic rate constants for B4C-50 mol%SiC composites at 1073 K were proportional to ambient oxygen partial pressures ranging between 30 and 100 kPa. The diffusion of oxygen molecules through the liquid borosilicate layer could be the rate-controlling process. The increase of SiC content in the B4C-SiC composites improved the oxidation resistance in both the mass gain and mass loss regions.

  200. Wet Oxidation of Silicon Carbide and Silicon Nitride Peer-reviewed

    T. Narushima, T. Goto, C. Ouchi, Y. Iguchi

    Metals Materials and Processes 15 (1-2) 177-185 2003/01

  201. Application of Srβ-alumina solid electrolyte to a CO2 gas sensor Peer-reviewed

    Takashi Goto, Gang He, Takayuki Narushima, Yasutaka Iguchi

    Solid State Ionics 156 (3-4) 329-336 2003/01

    DOI: 10.1016/S0167-2738(02)00681-1  

    ISSN:0167-2738

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    Srβ-alumina was synthesized in a SrO-MgO-Al2O3 system by solid state sintering, and the electrical conductivity was measured at 873-1673 K by impedance spectroscopy. The oxygen concentration cell method was applied to measure the ionic transport number. The ionic transport numbers were close to 1 in the temperature range between 1200 and 1600 K. Open- and closed-type CO2 gas sensors were constructed using the Srβ-alumina solid electrolyte and a Pt-SrCO3 auxiliary electrode. The CO2 sensors responded well to the changes of CO2 partial pressures at temperatures of 1073-1373 K. © 2003 Elsevier Science B.V. All rights reserved.

  202. Grain refinement of As cast austenite by dynamic recrystallization in HSLA steels Peer-reviewed

    N Fujita, T Narushima, Y Iguchi, C Ouchi

    ISIJ INTERNATIONAL 43 (7) 1063-1072 2003

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/isijinternational.43.1063  

    ISSN:0915-1559

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    Recent progress of steel manufacturing process necessitates to refine an extremely coarse austenitic microstructure evolved in a strand cast steel. Grain refinement of as cast austenite by dynamic recrystallization in HSLA steels was studied by using a hot working simulator. The specimens were prepared from a strand cast slab and the hot rolled steel plate of 0.09%C-1.14%Mn-2.26Ni-0.54Mo-0.045%V steel supplied from a steel plant, and also laboratory heat ingots of 0.14%C-1.45%Mn and 0.14%C-1A5%Mn-0.018%Ti steels. Variations of the true stress-true strain curve and dynamically recrystallized grain size with the deformation temperature, strain rate and the initial gamma grain size were investigated by hot compression test. It was confirmed that dynamically recrystallized grain size in as cast steels was determined simply by steady state flow stress or Zener-Hollomon parameter, but was not influenced by the initial grain size. Austenitic grain size variation with the reheating temperature in the as cast 0.09%C-2.26Ni-Mo-V steel was very small, and flow stress in the as cast Ti-bearing steel was markedly higher compared with those of the hot rolled plate of this steel or the C-Mn steel. These appeared to be caused by grain growth suppression due to the inter-dendritic phase enriched with carbon or alloying elements, and dispersion of the micro segregation region with high hardness, respectively. Finally, the direct hot deformation experiment after levitation melting and solidification was conducted, where the Ti-bearing steel was reheated at the temperature from 1743 to 1773 K and hot deformed by tensile strain at 1523 K. It was confirmed that very coarse gamma grain size in an order of mm was much refined down to 130 to 170 mum by dynamic recrystallization.

  203. Austenitic grain refinement in as cast HSLA steels by dynamic recrystallization Peer-reviewed

    N Fujita, T Narushima, Y Iguchi, C Ouchi

    THERMEC'2003, PTS 1-5 426-4 1095-1100 2003

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/MSF.426-432.1095  

    ISSN:0255-5476

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    Grain refinement of as cast austenite by dynamic recrystallization in HSLA steels was studied by using a hot working simulator. The hot compression and tensile specimens were prepared from 0.14%C-1.45%Mn and 0.018%Ti or 0.078%Zr bearing steels. Variations of the true stress-true strain curve and dynamically recrystallized grain size with the, deformation temperature, strain rate and the initial 7 grain size were investigated by hot compression test. The direct hot deformation experiment after levitation melting and solidification was conducted by using the tensile specimens, where the C-Mn and 0.018%Ti-bearing steels were reheated in the temperature range from 1743 K to 1773 K, cooled by various cooling rates, and then hot deformed by tensile strain at 1423 K to 1523 K. It was confirmed that dynamically recrystallized grain size was determined simply by steady state flow stress or Zener-Hollomon parameter, but was not influenced by the initial gram size. The very coarse 7 grain size with an order of mm was much refined down to 90 to 150 mum by dynamic recrystallization.

  204. Model studies of surfaces and interfaces in ceramics Peer-reviewed

    M Kitayama, T Narushima, K Tran, G Gronsky, AM Glaese

    ADVANCED CERAMICS AND COMPOSITES 247 341-347 2003

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/KEM.247.341  

    ISSN:1013-9826

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    For ceramics, surfaces and interfaces play a critical role in affecting the outcome of processing and sintering. The ultimate performance of ceramics and ceramic-containing composites and devices will also be impacted by surfaces and heterophase interfaces. This paper summarizes the development and application of model experiments for the study of ceramic/vapor and ceramic/metal interfaces. Lithography and etching when combined with solid-state diffusion bonding allow the internalization of controlled-geometry voids, whose morphological evolution can prove information on the coupling between surface energetics (Wulff shapes) and the kinetics of mass flow. Examples from studies - of undoped sapphire and silicon carbide will be presented. We have recently demonstrated that filling the voids with metal prior to diffusion bonding allows the fabrication of arrays of encapsulated, controlled-geometry, metal particles (nickel or copper) within a single crystal ceramic host (sapphire). The potential for using such embedded particles for studies of ceramic/metal interface energetics and shape relaxation kinetics in ceramic/metal systems will be discussed.

  205. Fatigue Property of Stainless Steel FES Electrode in Hanks' Solution Peer-reviewed

    Y. Iguchi Yasutaka, T. Narushima, K. Suzuki, S. Yoshida, M. Watanabe, T. Kinami, C. Ouchi

    Proc. of International Functional Electrical Stimulation Society 2002 217-219 2002/09

  206. Oxidation of silicon and silicon carbide in ozone-containing atmospheres at 973 K Peer-reviewed

    T Narushima, M Kato, S Murase, C Ouchi, Y Iguchi

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 85 (8) 2049-2055 2002/08

    Publisher: AMER CERAMIC SOC

    DOI: 10.1111/j.1151-2916.2002.tb00402.x  

    ISSN:0002-7820

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    The oxidation behavior of a silicon wafer, chemically vapor-deposited SiC, and single-crystal SiC was investigated in an oxygen-2%-7% ozone gas mixture at 973 K. The thickness of the oxide film that formed during oxidation was measured by ellipsometry. The oxidation rates in the ozone-containing atmosphere were much higher than those in a pure oxygen atmosphere. The parabolic oxidation kinetics were observed for both silicon and SiC. The parabolic rate constants varied linearly with the ozone-gas partial pressure. Inward diffusion of atomic oxygen formed by the dissociation of ozone gas through the SiO2 film apparently was the rate-controlling process.

  207. Solubilities and equilibrium distribution coefficients of oxygen and carbon in silicon Peer-reviewed

    T Narushima, A Yamashita, C Ouchi, Y Iguchi

    MATERIALS TRANSACTIONS 43 (8) 2120-2124 2002/08

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.43.2120  

    ISSN:1345-9678

    eISSN:1347-5320

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    Solubilities of oxygen and carbon in solid silicon at 1673 K were determined by using a chemical equilibrium technique. Solid silicon was heated at 1673 K in an oxygen atmosphere for 1800 ks, and then oxygen content in the solid silicon equilibrated with silica was measured by the inert gas fusion-IR absorption method. Carbon content in the solid silicon equilibrated with silicon carbide after heating at 1673 K in an Ar-5%CO atmosphere for 4860 ks was measured by the combustion-IR absorption method. Comparing these solubility values in solid silicon with those in liquid silicon that were previously reported by the present authors, the equilibrium distribution coefficients of oxygen and carbon in silicon at the melting point were evaluated to be 0.85 +/- 0.08 and 0.30 +/- 0.16, respectively.

  208. Behavior of oxygen in Ga-As melts with the range of As content up to 5 mass% equilibrated with B2O3 flux Peer-reviewed

    K Tajima, T Ogasawara, T Narushima, C Ouchi, Y Iguchi

    MATERIALS TRANSACTIONS 42 (11) 2434-2439 2001/11

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.42.2434  

    ISSN:1345-9678

    eISSN:1347-5320

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    The equilibrium between Ga-As melt, containing arsenic up to 5 mass%, and B2O3 flux was investigated from 1273 to 1523 K in a silica ampoule. The effect of arsenic on equilibrium contents of oxygen, boron and silicon in the melt was investigated. The results were analyzed using interaction parameters. The equilibrium distribution ratio of oxygen between Ga-As melt and B2O3 flux decreased with the increase of temperature, Ga2O3 content in the flux and arsenic content in the melt. The activity of Ga2O3 in the B2O3 flux was determined in the temperature range from 1273 to 1523 K, which is relevant to the practical process of crystal growth of GaAs.

  209. Calorimetric study on hydration of CaO-based oxides Peer-reviewed

    Y. Iguchi, T. Narushima, C. Izumi

    Journal of Alloys and Compounds 321 (2) 276-281 2001/06/14

    DOI: 10.1016/S0925-8388(01)00970-7  

    ISSN:0925-8388

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    Hydration behavior of compounds in Ca-(Si, Al or Fe)-O systems, CaO-(FeO or MnO) solid solutions and various kind of slags were investigated using calorimetric and dilatometric techniques in order to clarify the effects of CaO-based oxides on stability of steelmaking slag. Slow hydration rate and large volume expansion were observed in 3CaO·Al2O3, which was a harmful component for stabilizing slag. Heat of hydration and volume expansion of CaO solid solutions were almost the same as those of pure CaO in lower solute content region than 30-mole%, while the hydration rate decreased as MnO contents increased in higher solute content region. Hydration behavior of converter slag was dominated by free lime contained in the slag. It was suggested that 3CaO·Al2O3 affected hydration behavior of ladle furnace free (LF) slag because Al dissolution was detected after calorimetric measurements and slow expansion rates and higher heat of hydration than that calculated with free lime contents were observed for LF slag. © 2001 Elsevier Science B.V.

  210. High-temperature morphological evolution of lithographically introduced cavities in silicon carbide Peer-reviewed

    T Narushima, AM Glaeser

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 84 (5) 921-928 2001/05

    Publisher: AMER CERAMIC SOC

    DOI: 10.1111/j.1151-2916.2001.tb00769.x  

    ISSN:0002-7820

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    Internal cavities of controlled geometry and crystallography mere introduced in 6H silicon carbide single crystals by combining lithographic methods, ion-beam etching, and solid-state diffusion bonding. The morphologic evolution of these internal cavities (negative crystals) in response to anneals of up to 128 h duration at 1900 degreesC was examined using optical microscopy. Surface energy anisotropy and faceting had a strong influence on the geometric and kinetic characteristics of evolution. Decomposition of {1210} cavity edges into {101x} facets was observed after 16 h anneals, indicating that (1210) faces are not components of the Wulff shape. The shape evolution kinetics of penny-shaped cavities were also investigated. Experimentally observed evolution rates decreased much more rapidly with those predicted by a model in which surface diffusion was assumed to be rate limiting. This suggested that the development of facets and the associated loss of ledges and terraces during the initial stages of evolution resulted in an evolution process limited by the nucleation rate of attachment/detachment sites (ledges) on the facets.

  211. The Wulff shape of alumina: I. Modeling the kinetics of morphological evolution Peer-reviewed

    M Kitayama, T Narushima, WC Carter, RM Cannon, AM Glaeser

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 83 (10) 2561-2571 2000/10

    Publisher: AMER CERAMIC SOC

    DOI: 10.1111/j.1151-2916.2000.tb01591.x  

    ISSN:0002-7820

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    The rate at which fully facetted nonequilibrium shaped particles and pores approach their equilibrium (Wulff) shape via surface diffusion was modeled, and calculations relevant to alumina were performed to guide experimental studies. The modeling focuses on 2-D features, and considers initial particle/pore shape, size, surface energy anisotropy, and temperature (surface diffusivity) as variables. The chemical potential differences driving the shape change are expressed in terms of facet-to-facet differences in weighted mean curvature, Two approaches to modeling the surface flux are taken. One linearizes the difference in the mean chemical potential of adjacent facets, and assumes the flux is proportional to this difference. The other approach treats the surface chemical potential as a continuous function of position, and relates the displacement rate of the surface to the divergence of the surface flux. When consistent values for the relevant materials parameters are used, the predictions of these two modeling approaches agree to within a factor of 1.5, As expected, the most important parameters affecting the evolution times are the cross-sectional area (volume in 3-D) and the temperature through its effect on the surface diffusivity, Pores of micrometer size are predicted to reach near-equilibrium shapes in reasonable times at temperatures as low as 1600 degrees C. The detailed geometry of the initial nonequilibrium shape and the Wulff shape appear to have relatively minor effects on the times required to reach a near-equilibrium shape.

  212. The Wulff shape of alumina: II. Experimental measurements of pore shape evolution rates Peer-reviewed

    M Kitayama, T Narushima, AM Glaeser

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 83 (10) 2572-2583 2000/10

    Publisher: WILEY-BLACKWELL

    DOI: 10.1111/j.1151-2916.2000.tb01592.x  

    ISSN:0002-7820

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    The rate at which a facetted tetragonal cavity of nonequilibrium shape approaches a cubic equilibrium (Wulff) shape via surface diffusion was modeled. The shape relaxation rate of a facetted "stretched cylinder" was also modeled, For the first geometry, only an approximate solution based on linearizing the mean potential difference between the source and sink facets was obtained. For the stretched cylinder, both an approximate and an exact solution can be obtained; the approximate solution underestimates the evolution rate by a factor of approximate to 2, To assess the applicability of the models, nonequilibrium shape pores of identical initial geometry (approximate to 20 mu m x 20 mu m x 0.5 mu m) were introduced into (0001), {10 (1) over bar 2}, {11 (2) over bar 0}, and {10 (1) over bar 0} surfaces of sapphire single crystals using microfabrication techniques, ion-beam etching, and hot pressing. The large (approximate to 20 pm x 20 mu m) faces of the pore are low-index surfaces whose nature is dictated by the wafer orientation. A series of anneals was performed at 1900 degrees C, and the approach of the pore shape to an equilibrium shape was monitored, The kinetics of shape evolution are highly sensitive to the crystallographic orientation and stability of the low-index surface that dominates the initial pore shape. The measured variations of the pore aspect ratio were compared to those predicted by the kinetic model. The observations suggest that when the initial bounding surface is unstable, shape relaxation may be controlled by diffusion. However, surface-attachment-limited kinetics (SALK) appears to play a major role in determining the pore shape evolution rate in cases where the initial bounding surfaces have orientations that are part of the Wulff shape.

  213. Sulfidation of Iron and Iron Oxide at 573 to 773 K Peer-reviewed

    T.Inaba, M.Sakuma, M.Watanabe, T.Narushima, C.Ouchi, Y.Iguchi

    Proceedings of the International Symposium on High-Temperature Corrosion and Protection 2000 143-148 2000/08

  214. Fatigue Properties of FES Electrodes in Saline Solution Peer-reviewed

    M. Watanabe, T. Kinami, T. Narushima, C. Ouchi, Y. Iguchi, Y. Handa, N. Hoshimiya

    Proceedings of the International Workshop on FES 24-27 2000/08

  215. Development of Implanted Bio-materials and Application to FES Electrodes as the Interface between Stimulator and Nerve Peer-reviewed

    Y.Iguchi, C.Ouchi, T.Narushima, M.Watanabe, T.Kinami, T.Nishikawa, N.Hoshimiya, Y.Handa

    Proceedings of 5th Annual Conference of the International Functional Electrical Stimulation Society 253-256 2000/07

  216. Collaboration and Technology Transfer between Universities and Industries on Development of Electrodes as the Interface for FES (Functional Electrical Stimulation) Peer-reviewed

    Y. Iguchi, T. Narushima, M. Watanabe, T. Kinami, N. Hoshimiya, Y. Handa

    Proceedings of The International Conference on Steel and Society (ICSS2000) 396-401 2000/07

  217. Activity of Ga2O3 in B2O3 flux and standard free energies of formation of GaBO3 and InBO3 Peer-reviewed

    K Tajima, Y Hino, T Narushima, Y Iguchi

    MATERIALS TRANSACTIONS JIM 41 (6) 714-718 2000/06

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans1989.41.714  

    ISSN:0916-1821

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    The equilibrium between liquid III group metal and B2O3 flux was investigated thermodynamically as a fundamental study on impurity control in single crystal growth of III-V group compound semiconductors. The oxygen distribution ratio between gallium melt and B2O3 flux and the activity of Ga2O3 in B2O3 Bur were clarified at 1373 and 1273 K by measuring oxygen contents in gallium melt and Ga(2)O(3)contents in B2O3 flux. The standard free energies of formation of GaBO3 and InBO3 were determined by measuring oxygen content of liquid Ill group metal (gallium or indium) equilibrated with B2O3 flux and GaBO3 or InBO3: Delta G degrees(GaBO3) = -1.14 x 10(6) + 251T (J) (T : 1123 similar to 1173 K) Delta G degrees(InBO3) = -1.02 x 10(6) + 220T (J) (T : 1223 similar to 1373 K).

  218. High Temperature CO<SUB>2</SUB> Gas Sensor Using Sr β Alumina Peer-reviewed

    G.He, T.Goto, T.Narushima, Y.Iguchi

    Proceedings of 4th East Asian Conference on Chemical Sensor 183-186 1999/10

  219. Electrical conductivity and ionic transference number of Sr and Baβ-aluminas Peer-reviewed

    G. He, T. Goto, T. Narushima, Y. Iguchi

    Solid State Ionics 124 (1) 119-124 1999/09/01

    Publisher: Elsevier Science Publishers B.V.

    DOI: 10.1016/S0167-2738(99)00128-9  

    ISSN:0167-2738

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    Ba and Srβ-alumina ionic conductors were synthesized by solid state sintering at 2033 to 2073 K and their electrical conductivities were measured by a.c. impedance spectroscopy. The electrical conductivities at 1673 K were 2.05×10-2 and 4.6×10-3 S m-1 for Sr and Baβ-aluminas, respectively. An oxygen concentration cell and d.c. polarization methods were applied to measure the ionic transference numbers. The values obtained by the two methods were almost in agreement at more than 1400 and 1673 K for Srβ-alumina and Baβ-alumina, respectively. Srβ-alumina could have slightly greater ionic transference numbers than Baβ-alumina.

  220. Evaluation of Fatigue Properties of High Nitrogen High Manganese Austenite Stainless Steel as an FES Electrode Peer-reviewed

    M.Watanabe, T.Narushima, T.Kinami, Y.Iguchi, N.Hoshimiya, Y.Handa

    Proceedings of 4th Annual Conference of the IFESS 121 121-123 1999/08

  221. Electrical conductivity of alkaline-earth metal β-aluminas and their application to a CO2 gas sensor Peer-reviewed

    G. He, T. Goto, T. Narushima, Y. Iguchi

    Solid State Ionics 121 (1) 313-319 1999

    Publisher: Elsevier Science Publishers B.V.

    DOI: 10.1016/S0167-2738(99)00063-6  

    ISSN:0167-2738

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    Sr and Baβ-aluminas in a single phase were synthesized in the MO-MgO-Al2O3 (M = Sr and Ba) system by a solid state sintering method. The electrical conductivity was measured at 873 to 1473 K by an AC impedance method. The total electrical conductivities of Srβ-alumina and Baβ-alumina were 1.2×10-2 S m-1 and 6.7×10-4 S m-1 at 1473 K, respectively. A CO2 gas sensor using the Srβ-alumina was constructed. The sensor could be used at more than 1000 K.

  222. Synthesis and Electrical Property Measurements of Baβ-Alumina in a BaO-MgO-Al_2O_3 System

    HE Gang, NARUSHIMA Takayuki, GOTO Takashi, HIRAI Toshio, IGUCHI Yasutaka

    Journal of the Ceramic Society of Japan 106 (1239) 1048-1050 1998/11/01

    Publisher: The Ceramic Society of Japan

    DOI: 10.2109/jcersj.106.1048  

    ISSN:1882-1022

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    An ionic conductor, Ba β-alumina, was synthesized in a BaO-MgO-Al_2O_3 ternary system by solid state sintering at 2023 to 2073 K. The Ba β-alumina with a composition of BaO : MgO : Al_2O_3 = 1 : 1 : 5 was in a single phase. Its relative density was 96% of the theoretical density. The electrical conductivity of Ba β-alumina was 4.6 × 10^<-3> S・m^<-1> at 1673 K and the activation energy was 126.82 kJ・mol^<-1>. The mobile ion could be Ba^<2+>, and its ionic transport number was about 0.8 to 0.9 at 1073 to 1673 K.

  223. Synthesis and electrical property measurements of Ba beta-alumina in a BaO-MgO-Al2O3 system Peer-reviewed

    G He, T Narushima, T Goto, T Hirai, Y Iguchi

    JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 106 (11) 1048-1050 1998/11

    Publisher: CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI

    DOI: 10.2109/jcersj.106.1048  

    ISSN:1882-0743

    eISSN:1348-6535

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    An ionic conductor, Ba beta-alumina, was synthesized in a BaO-MgO-Al2O3, ternary system by solid state sintering at 2023 to 2073 K. The Ba beta-alumina with a composition of BaO :MgO :Al2O3=1 : 1 : 5 was in a single phase. Its relative density was 96% of the theoretical density. The electrical conductivity of Ba beta-alumina was 4.6 x 10(-3) S.m(-1) at 1673 K and the activation energy was 126.82 kJ.mol(-1). The mobile ion could be Ba2+ and its ionic transport number was about 0.8 to 0.9 at 1073 to 1673 K.

  224. Effect of alloying elements on carbon solubility in liquid silicon equilibrated with silicon carbide Peer-reviewed

    K Yanaba, Y Matsumura, T Narushima, Y Iguchi

    MATERIALS TRANSACTIONS JIM 39 (8) 819-823 1998/08

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans1989.39.819  

    ISSN:0916-1821

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    Carbon solubilities in liquid Si-X alloys (where X represents the alloying elements) that have been equilibrated with silicon carbide were determined in the temperature range between 1723 and 1873 K. The Si-X alloy was melted in a silicon carbide crucible under Ar-CO mixture gas flowing. After the equilibrium between the liquid silicon and silicon carbide was established, the carbon content and alloying element (X) content of the quenched sample were measured. The carbon solubility increased as B, Al, P and Ca contents increased in the liquid silicon, but decreased as Ti, V, Cr, Mn, Fe, Co, Ni and Cu contents increased. The effect of the alloying elements on the carbon solubility was discussed thermodynamically.

  225. High-temperature oxidation of CVD silicon carbide -passive/active oxidation and bubble formation Peer-reviewed

    T Goto, H Homma, T Hirai, T Narushima, Y Iguchi

    HIGH TEMPERATURE CORROSION AND MATERIALS CHEMISTRY, PROCEEDINGS 98 (9) 395-408 1998

    Publisher: ELECTROCHEMICAL SOCIETY INC

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    The active oxidation rates of CVD SiC increased with increasing oxygen partial pressure (P-O2) in Ar-O-2 atmosphere, and the active to passive transition happened sharply at a critical P-O2. In CO-CO2 atmosphere, the active oxidation rates showed a maximum at about P-CO2/P-CO=10(-3). With increasing P-CO2/P-CO, the active oxidation changed gradually to the passive oxidation forming a solid phase of SiO2. The Wagner criterion well explained the active to passive transition behavior in both Ar-O-2 and CO-CO2 atmospheres. The passive oxidation kinetics in the temperature range between 1800 and 2000 K was linear with an activation energy of 110 kJ/mol in Ar-O-2, but was parabolic with that of 150 kJ/mol in Ar-CO2. No bubble formation was observed in both Ar-O-2 and Ar-CO2 atmospheres at less than 1990 K.

  226. Preparation of Sr β-Alumina lonic Conductors and Their a.c. Impedance Measurements

    GANG He, HAYASAKA Yasukazu, NARUSHIMA Takayuki, GOTO Takashi, HIRAI Toshio, IGUCHI Yasutaka

    Journal of the Ceramic Society of Japan 105 (1228) 1067-1071 1997/12/01

    Publisher: The Ceramic Society of Japan

    DOI: 10.2109/jcersj.105.1067  

    ISSN:1882-1022

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    β-alumina type ionic conductors were synthesized in the SrO-MgO-Al_2O_3 system by a direct sintering method and their electrical conductivity was measured at 873 to 1373 K by an a.c.impedance method in order to apply the β-alumina to solid electrolyte of a gas sensor at high temperatures. Sr β-aluminas in a single phase were obtained in the composition range of SrO : MgO : Al_2O_3=1 : 1 : 4.8-5.2. The bulk and grain boundary conductivities were separated from the total conductivity at SrO : MgO : Al_2O_3=1 : 1 : 4.8 and 1 : 1 : 5.0. The bulk conductivity of the Sr β-alumina was around 6.7×10^<-3> S・m^<-1> at 1373 K.

  227. Preparation of Sr beta-alumina ionic conductors and their ac impedance measurements Peer-reviewed

    H Gang, Y Hayasaka, T Narushima, T Goto, T Hirai, Y Iguchi

    JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 105 (12) 1067-1071 1997/12

    Publisher: CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI

    DOI: 10.2109/jcersj.105.1067  

    ISSN:1882-0743

    eISSN:1348-6535

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    beta-alumina type ionic conductors were synthesized in the SrO-MgO-Al2O3 system by a direct sintering method and their electrical conductivity was measured at 873 to 1373 K by an a.c. impedance method in order to apply the beta-alumina to solid electrolyte of a gas sensor at high temperatures. Sr beta-aluminas in a single phase were obtained in the composition range of SrO : MgO : Al2O3 =1 : 1 : 4.8-5.2. The bulk and grain boundary conductivities were separated from the total conductivity at SrO : MgO : Al2O3=1 : 1 : 4.8 and 1 : 1 : 5.0. The bulk conductivity of the Sr beta-alumina was around 6.7 x 10(-3) S.m(-1) at 1373 K.

  228. Solubility of carbon in liquid silicon equilibrated with silicon carbide Peer-reviewed

    K Yanaba, M Akasaka, M Takeuchi, M Watanabe, T Narushima, Y Iguchi

    MATERIALS TRANSACTIONS JIM 38 (11) 990-994 1997/11

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans1989.38.990  

    ISSN:0916-1821

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    The solubility of carbon in liquid silicon equilibrated with silicon carbide was determined in the temperature range from 1723 to 1873 K. Silicon was melted in a silicon carbide crucible with an Ar-CO mixture gas flowing. Carbon in silicon was analyzed by the combustion-IR absorption method. The temperature dependence of the carbon solubility in liquid silicon can be represented by the following equation: log (C-(c under bar)/mass%)=3.63-9660/T(+/-0.02) (T:1723-1873 K) The carbon solubility at the melting point of silicon was calculated to be 79 ppm (9.1 x 10(18) atoms.cm(-3)). The level of oxygen impurities in the melt was much lower than that of liquid silicon equilibrated with solid silica. The standard Gibbs free energy change for carbon dissolution in liquid silicon can be represented as: C(s)=(C) under bar C(1 mass%, in liquid silicon) Delta G degrees=7.20x10(4)-11.4Tlog T+6.20T (J).

  229. Oxygen Distribution between Molten B<SUB>2</SUB>O<SUB>3</SUB> Flux and Indium or Gallium Peer-reviewed

    Y.Iguchi, M.Kinoshita, Y.Hino, T.Narushima

    Proc. of 5th Int. Conf. on Molten Slags, Fluxes and Salts 317-320 1997/01

  230. Determination of Free Lime Contents in Slags by Solution Calorimetry Peer-reviewed

    Y.Muraki, T.Narushima, Y.Iguchi

    ISIJ International 36 (12) 243-246 1996/12

    Publisher: The Iron and Steel Institute of Japan

    DOI: 10.2355/isijinternational.36.Suppl_S243  

    ISSN:0915-1559

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    Free lime content in slag was investigated using a solution calorimetric technique in order to clarify hydration behavior of the free lime. After confirmation of the agreement between the heat of hydration of pure CaO obtained by this method and the calculated value, the heats of hydration of slags with different free lime contents were measured. Good correlation between the free lime contents and the heats of the hydration was indicated though small amounts of calcium silicates, calcium aluminates, MgO and calcium ferrite in the slags might be hydrated in addition to the free lime.

  231. High-Temperature Oxidation of CVD Silicon-Based Ceramics Peer-reviewed

    T.Goto, T.Hirai, T.Narushima, Y.Iguchi

    Ceramic Transaction 71 245-257 1996/10

  232. Oxygen Distribution between Molten III Group Metals and B<SUB>2</SUB>O<SUB>3</SUB> Flux Peer-reviewed

    Y.Iguchi, M.Kinoshita, D.Sajuti, S.Yoshida, Y.Hino, T.Narushima

    Proc. of Int. Symp. on Metall. and Mater. of Non-Ferrous Metals and Alloys 45-49 1996/10

  233. In situ observation of oxide films formed during thermal oxidation of SiC-B4C composite using Raman spectroscopy Peer-reviewed

    T Narushima, M Maruyama, H Arashi, T Goto, T Hirai, Y Iguchi

    CORROSION OF ADVANCED CERAMICS 113 99-104 1996

    Publisher: TRANS TECH PUBLICATIONS LTD

    DOI: 10.4028/www.scientific.net/KEM.113.99  

    ISSN:1013-9826

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    Oxidation behaviour of SiC-B4C composites at 1073 K was investigated by laser Raman spectroscopy. In situ Raman spectra of the surface of the composite indicated the formation of carbon and borosilicate as oxidation products. The carbon was enriched in the part of borosilicate closer to the oxide/composite interface using a micro-Raman spectroscopic system. The oxidation resistance of the composites was improved with increasing SiC content.

  234. Complex oxide films formed during thermal oxidation of liquid aluminum alloys Peer-reviewed

    Y Iguchi, T Narushima, M Marauyama, T Shiozawa, H Arashi

    DESIGN FUNDAMENTALS OF HIGH TEMPERATURE COMPOSITES, INTERMETALLICS, AND METAL-CERAMICS SYSTEMS 337-343 1996

    Publisher: MINERALS, METALS & MATERIALS SOC

  235. High-Temperature Oxidation Behavior of CVD SiC and Si<SUB>3</SUB>N<SUB>4</SUB> Peer-reviewed

    T.Goto, T.Hirai, T.Narushima, Y.Iguchi

    Proc. 95' Beijing Inter. Conf. for Surface Science and Engineering 401-406 1995/09

  236. OXYGEN SOLUBILITY IN LIQUID SI-X (X=SB, B, P AND AS) ALLOYS Peer-reviewed

    T NARUSHIMA, K MATSUZAWA, M MAMIYA, Y IGUCHI

    MATERIALS TRANSACTIONS JIM 36 (6) 763-769 1995/06

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans1989.36.763  

    ISSN:0916-1821

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    Oxygen solubilities in liquid Si-X (X=Sb, B, P and As) alloys equilibrated with solid silica (cristobalite) were determined in the temperature range between 1693 and 1823 K. Si-X alloys were melted in a silica crucible with oxygen gas flowing. After the equilibrium between a silicon melt and silica was established, the contents of oxygen and the alloying elements (X) in the silicon melt were determined. It was found that the oxygen solubility increased with increasing alloying element in the melt. The effect of the alloying elements on the oxygen solubility was discussed thermodynamically.

  237. DEVELOPMENT OF IN-SITU OBSERVATION SYSTEM FOR OXIDE-FILMS FORMED DURING THERMAL-OXIDATION USING RAMAN-SPECTROSCOPY Peer-reviewed

    T NARUSHIMA, N KIKUCHI, M MARUYAMA, H ARASHI, Y NISHINA, Y IGUCHI

    TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN 81 (6) 607-612 1995/06

    Publisher: IRON STEEL INST JAPAN KEIDANREN KAIKAN

    DOI: 10.2355/tetsutohagane1955.81.6_607  

    ISSN:0021-1575

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    In-situ observation system for oxidation films using laser Raman spectroscopy was constructed and the growth process of oxide films during thermal oxidation of Fe-6.5mass%Si alloy at 1073K in O-2, CO2 and CO-CO2 (P-CO/P-CO2=1) atmospheres was investigated. In-situ Raman spectra of the oxide films formed in these atmospheres could be obtained using the system with an SN-filter and a chopper unit to reduce the effect of Rayleigh scattering and thermal radiation. In a CO2 atmosphere strong Raman peaks of Fe3O4 and alpha-Fe2O3 were observed even in the early stage of oxidation of the alloy, which suggested that the oxidation rate in the CO2 atmosphere was higher than that in the O-2 or CO-CO2 atmosphere. Since the difference of oxidation behavior in these atmospheres was not detected by thermogravimetry, the usefulness of the system at high temperatures was confirmed.

  238. High-Temperature Oxidation Behavior of CVD Silicon Carbide and Silicon Nitride Peer-reviewed

    T. Goto, T. Narusima, Y. Iguchi, T. Hirai

    Proc. 6th Symp. High-Performance Materials for Severe Environments 331-338 1995

  239. OXYGEN SOLUBILITY IN LIQUID GALLIUM AND LIQUID INDIUM Peer-reviewed

    T NARUSHIMA, D SAJUTI, K SAEKI, SY YOSHIDA, Y IGUCHI

    JOURNAL OF THE JAPAN INSTITUTE OF METALS 59 (1) 37-43 1995/01

    Publisher: JAPAN INST METALS

    DOI: 10.2320/jinstmet1952.59.1_37  

    ISSN:0021-4876

    eISSN:1880-6880

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    The oxygen solubility in liquid gallium or liquid indium equilibrated with solid Ga2O3 or In2O3, respectively, was determined in an alumina crucible which was less reactive than the silica one. After establishment of an equilibrium between the liquid metal (gallium or indium) and an oxide (Ga2O3 or In2O3) formed on the surface of the metal during melting, the oxygen content in quenched gallium or indium was analyzed by the inert gas fusion-IR absorption method. The optimum conditions for oxygen extraction were decided for a furnace power and a bath composition. The temperature dependence of oxygen solubility in liquid gallium or liquid indium was expressed as the following equations: log (C (o) under bar/mass% in liquid gallium) = -6200/ T+2.61(+/-0.119) (T:1123 similar to 1523 K), log (C (o) under bar/mass% in liquid indium) = - 6600/T+3.77(+/-0.074) (T:1073 similar to 1373 K). Using the temperature dependence of the oxygen solubility in the present work and the standard free energy of formation of Ga2O3 or In2O3 in the literature, the standard free energy change for oxygen dissolution in liquid gallium or liquid indium could be represented as follows: 1/2O(2)(g)=(O) under bar(mass%, in liquid gallium), Delta G degrees = -2.45 x 10(5)+59.6T(J), 1/2O(2)(g)=(O) under bar(mass%, in liquid indium), Delta G degrees = -1.79 x 10(5)+33.8T(J).

  240. HIGH-TEMPERATURE OXIDATION OF CHEMICALLY VAPOR-DEPOSITED SILICON-NITRIDE IN A CARBON-MONOXIDE CARBON-DIOXIDE ATMOSPHERE Peer-reviewed

    T NARUSHIMA, T GOTO, J HAGIWARA, Y IGUCHI, T HIRAI

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 77 (11) 2921-2925 1994/11

    Publisher: AMER CERAMIC SOC

    DOI: 10.1111/j.1151-2916.1994.tb04525.x  

    ISSN:0002-7820

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    Oxidation behavior of chemically vapor-deposited silicon nitride (CVD-Si3N4) in CO-CO2 atmospheres between 1823 and 1923 K was investigated using a thermogravimetric technique. Mass loss of Si3N4 (active oxidation) was observed in a region of P-CO2/P-CO &lt; 1, while mass gain (passive oxidation) was observed at around P-CO2/P-CO 10. In the active oxidation region below P-CO2/P-CO 10(-4), carbon particles were formed on the Si3N4 surface as an oxidation product, and the mass-loss rates were independent of P-CO2/P-CO. In the active oxidation region above P-CO2/P-CO 10(-4), the mass-loss rates decreased with increasing P-CO2/P-CO. The critical P-CO2/P-CO value from the active to passive oxidation was 2 orders of magnitude larger than the calculated value predicted from the Wagner model.

  241. NITROGEN SOLUBILITY IN LIQUID SILICON Peer-reviewed

    T NARUSHIMA, N UEDA, M TAKEUCHI, F ISHII, Y IGUCHI

    MATERIALS TRANSACTIONS JIM 35 (11) 821-826 1994/11

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans1989.35.821  

    ISSN:0916-1821

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    The nitrogen solubility in,liquid silicon equilibrated with beta-Si3N4 was determined in the temperature range between 1723 and 1873 K. A silicon nitride crucible and an N-2-H-2 atmosphere (N-2:H-2=4:1, total pressure=0.1 MPa) were employed for the melting of silicon to secure the Si(1)/Si3N4(s) equilibrium. Nitrogen in silicon was analyzed by the Kjeldahl method. The temperature dependence of nitrogen solubility (C ($) under bar($) under bar N) in liquid silicon was represented by the following equation: log (C-$ under bar N/mass%)=2.410-9759s/T (+/-0.24) (T:1723-1873 K). Since oxygen contents in the silicon melt were much smaller than the oxygen solubility, the effect of oxygen in liquid silicon on the nitrogen solubility could be ignored. The nitrogen solubility at the melting point of silicon (1685 K) by extrapolation was around 4 ppm (4 x 10(17) atoms cm(-3)), which was one order of magnitude smaller than the literature values reported previously. The standard free energy change for nitrogen dissolution could be represented as: 1/2N(2)=($) under bar N(mass%, in liquid silicon), Delta G degrees= -4.45 x 10(4)+66.4T(J). The correlation between the standard enthalpy change for nitrogen dissolution in liquid silicon and the standard enthalpy of formation of silicon nitride at 298 K per mol of nitrogen agreed with those for other liquid metals. Therefore, the values of nitrogen solubility obtained in the present work were considered to be

  242. HIGH-TEMPERATURE ACTIVE OXIDATION AND ACTIVE-TO-PASSIVE TRANSITION OF CHEMICALLY VAPOR-DEPOSITED SILICON-NITRIDE IN N-2 O-2 AND AR O-2 ATMOSPHERES Peer-reviewed

    T NARUSHIMA, T GOTO, Y YOKOYAMA, J HAGIWARA, Y IGUCHI, T HIRAI

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 77 (9) 2369-2375 1994/09

    Publisher: AMER CERAMIC SOC

    DOI: 10.1111/j.1151-2916.1994.tb04607.x  

    ISSN:0002-7820

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    The oxidation behavior of chemically vapor-deposited silicon nitride in N-2-O-2 acid Ar-O-2 atmospheres was studied using a thermogravimetric technique at temperatures 1823 to 1923 K. Active oxidation was observed at low oxygen partial pressures. The active oxidation rates increased with increasing oxygen partial pressure (P-O2) up to a certain P-O2 and then passive oxidation occurred. The transition oxygen partial pressures from active to passive oxidation were determined. The rate-controlling step for the active oxidation could be oxygen diffusion through a gaseous boundary layer near the S3N4 surface. Decomposition of SI3N4 does not seem to be associated with the mass loss behavior. The Wagner model was employed to explain the oxidation behavior.

  243. High-Temperature Passive/Active Oxidation for CVD SiC and Si<SUB>3</SUB>N<SUB>4</SUB> Peer-reviewed

    T.Goto, T.Narushima, Y.Iguchi, T.Hirai

    Ceramic Transactions 42 307-318 1994/08

  244. OXYGEN SOLUBILITY IN LIQUID SILICON Peer-reviewed

    T NARUSHIMA, K MATSUZAWA, Y MUKAI, Y IGUCHI

    MATERIALS TRANSACTIONS JIM 35 (8) 522-528 1994/08

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans1989.35.522  

    ISSN:0916-1821

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    The oxygen solubility in liquid silicon equilibrated with solid silica (cristobalite) was determined in the temperature range between 1693 and 1823 K. Silicon was melted in a silica crucible with oxygen gas flowing. Oxygen in a quenched sample was analyzed by the inert gas fusion-IR absorption method. The optimum furnace power and bath composition for oxygen extraction were determined. The temperature dependence of oxygen solubility in liquid silicon could be expressed as the following equation. log (C-O under bar/mass%)= -4620/T+0.332(+/-0.06)(T:1693 similar to 1823 K) The oxygen solubility in liquid silicon at the melting point (1685 K) was calculated to be 39 ppm (3.4 x 10(18) atoms . cm(-3)). Using the temperature dependence of oxygen solubility in the present work and the standard free energy of formation of silica in the literature, the standard free energy change follows: 1/2O(2)(g)=(O) under bar(mass%, in liquid silicon) Delta G degrees= -3.88 x 10(5)+95.6 T(J) According to the previously reported correlations between the standard enthalpy change for oxygen dissolution in liquid metals and the standard enthalpy of the formation of the metal oxides at 298 K per mol of oxygen, and the standard enthalpy change and the standard entropy change for oxygen dissolution in liquid metals, it was suggested that the present Delta G degrees value, i.e., the oxygen solubility in liquid silicon, was reasonable.

  245. Theoretical estimation of the effect of minor elements on the solubility of oxygen in silicon melt Peer-reviewed

    Y. Waseda, K. T. Jacob, Y. Iguchi, T. Narushima

    Journal of Crystal Growth 139 (3-4) 357-362 1994/05/02

    DOI: 10.1016/0022-0248(94)90188-0  

    ISSN:0022-0248

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    The effect of fourteen minor elements (Al, As, B, Bi, C, Ga, Ge, In, N, P, Pb, S, Sb and Sn) on the solubility of oxygen in silicon melt has been estimated using a recently developed theoretical equation, with only fundamental physical parameters such as hard sphere diameter, atomic volume and molar heat of solution at infinite dilution as inputs. The results are expressed in the form of interaction parameters. Although only limited experimental data are available for comparison, the theoretical approach appears to predict the correct sign, but underestimates the magnitude of the interaction between oxygen and alloying elements. The present theoretical approach is useful in making qualitative predications on the effect of minor elements on the solubility of oxygen in silicon melt, when direct measurements are not available. © 1994.

  246. ACTIVE-TO-PASSIVE TRANSITION AND BUBBLE FORMATION FOR HIGH-TEMPERATURE OXIDATION OF CHEMICALLY VAPOR-DEPOSITED SILICON-CARBIDE IN CO-CO2 ATMOSPHERE Peer-reviewed

    T NARUSHIMA, T GOTO, Y YOKOYAMA, M TAKEUCHI, Y IGUCHI, T HIRAI

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 77 (4) 1079-1082 1994/04

    Publisher: AMER CERAMIC SOC

    DOI: 10.1111/j.1151-2916.1994.tb07273.x  

    ISSN:0002-7820

    More details Close

    Oxidation behavior of chemically vapor-deposited SiC in CO-CO2 atmospheres (0.1 MPa) was investigated using a thermogravimetric technique at temperatures from 1823 to 1923 K. Active or passive oxidation was observed depending on temperature and CO2/CO partial pressure ratio (P(CO2)/P(CO)). The critical P(CO2)/P(CO) value for the transition was 10(2) times as large as a theoretical value calculated from the Wagner model. In the passive oxidation above 1873 K, SiO2 bubbles were grown. The expansion and rupture of bubbles caused cyclic rapid mass gain and mass loss.

  247. Active/Passive oxidation Behavior of CVD Silicon Carbide Peer-reviewed

    T. Goto, T. Narusima, Y. Iguchi, T. Hirai

    Proc. 5th Symp. High-Performance Materials for Severe Environments 375-382 1994

  248. ACTIVE TO PASSIVE TRANSITION IN THE HIGH-TEMPERATURE OXIDATION OF CVD SIC AND SI3N4 Peer-reviewed

    T GOTO, T NARUSHIMA, Y IGUCHI, T HIRAI

    CORROSION OF ADVANCED CERAMICS 267 165-176 1994

    Publisher: KLUWER ACADEMIC PUBL

    ISSN:0168-132X

  249. HIGH-TEMPERATURE ACTIVE OXIDATION OF CVD-SI3N4 IN N2-O2 ATMOSPHERE Peer-reviewed

    T NARUSHIMA, J HAGIWARA, N KIKUCHI, Y IGUCHI, T GOTO, T HIRAI

    ADVANCED MATERIALS '93, I - A & B 14 (A & B) 281-284 1994

    Publisher: ELSEVIER SCIENCE PUBL B V

  250. PHASE-DIAGRAMS OF THE GA2O3-B2O3 AND IN2O3-B2O3 BINARY-SYSTEMS Peer-reviewed

    D SAJUTI, M YANO, T NARUSHIMA, Y IGUCHI

    MATERIALS TRANSACTIONS JIM 34 (12) 1195-1199 1993/12

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans1989.34.1195  

    ISSN:0916-1821

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    The solubility of Ga2O3 or In2O3 in liquid B2O3 which is used as a flux for pulling single crystal of III-V compounds has been measured by the sampling method in the temperature range of 973 to 1573 K. The gallium or indium contents in the samples were analyzed by ICP atomic emission spectroscopy. The phase equilibrium in the Ga2O3-B2O3 or In2O3-B2O3, binary system has been determined by X-ray diffraction and differential thermal analysis for the precipitates in liquid phase or the binary compounds which were synthesized from pure oxides. The solid phase equilibrated with liquid phase was clarified. The phase diagrams of the Ga2O3-B2O3 and In2O3-B2O3 binary systems were constructed.

  251. HIGH-TEMPERATURE ACTIVE OXIDATION OF CHEMICALLY VAPOR-DEPOSITED SILICON-CARBIDE IN CO-CO2 ATMOSPHERE Peer-reviewed

    T NARUSHIMA, T GOTO, Y YOKOYAMA, Y IGUCHI, T HIRAI

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 76 (10) 2521-2524 1993/10

    Publisher: AMER CERAMIC SOC

    DOI: 10.1111/j.1151-2916.1993.tb03975.x  

    ISSN:0002-7820

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    Active oxidation behavior of CVD-SiC in CO-CO2 atmospheres was investigated using a thermogravimetric technique in the temperature range between 1823 and 1923 K. The gas pressure ratio, P(CO2)/P(CO), was controlled between 10(-4) and 10(-1) at 0.1 MPa. Active oxidation rates (mass loss rates) showed maxima at a certain value of P(CO2)/P(CO), (P(CO2)/P(CO))*. In a P(CO2)/P(CO) region lower than the (P(CO2)/P(CO))*, a carbon layer was formed on the SiC surface. In a P(CO2)/P(CO) region higher than the (P(CO2)/P(CO))*, silica particles or a porous silica layer was observed on the SiC surface.

  252. OXIDATION OF CHEMICALLY VAPOR-DEPOSITED SILICON-NITRIDE IN DRY OXYGEN AT 1923-K TO 2003-K Peer-reviewed

    T NARUSHIMA, RY LIN, Y IGUCHI, T HIRAI

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 76 (4) 1047-1051 1993/04

    Publisher: AMER CERAMIC SOC

    DOI: 10.1111/j.1151-2916.1993.tb05333.x  

    ISSN:0002-7820

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    Oxidation of chemically vapor-deposited Si3N4 was studied in dry oxygen between 1923 and 2003 K under a total pressure of 0.1 MPa using a thermogravimetric technique. At 1923 to 1953 K, a parabolic rate mechanism prevailed for the oxidation reaction. From 1973 K, the oxidation reaction exhibited a mixed linear-parabolic rate mechanism. At 2003 K, on the other hand, the oxidation of Si3N4 showed a linear behavior. Both amorphous silica and cristobalite were identified as reaction products on the oxidized Si3N4 surface using X-ray diffraction analysis. The percentage of cristobalite in the surface oxide scale was determined from the X-ray diffraction pattern. It was found that, at 2003 K, only amorphous silica was formed. The parabolic rate constants (K(p)) obtained from this study were close to those obtained in the literature.

  253. SOLUBILITY OF OXYGEN, NITROGEN AND CARBON IN LIQUID SILICON Peer-reviewed

    Y IGUCHI, T NARUSHIMA

    FIRST INTERNATIONAL CONFERENCE ON PROCESSING MATERIALS FOR PROPERTIES 437-440 1993

    Publisher: MINERALS, METALS & MATERIALS SOC

  254. Solubility of Ga<SUB>2</SUB>O<SUB>3</SUB> or In<SUB>2</SUB>O<SUB>3</SUB> in Liquid B<SUB>2</SUB>O<SUB>3</SUB> Peer-reviewed

    D.Sajuti, M.Yano, T.Narushima, Y.Iguchi

    Proceedings of the 4th International Conference on Molten Slags and Fluxes 614-619 1992/06

  255. HIGH-TEMPERATURE OXIDATION OF CVD-SIC IN CO-CO2 ATMOSPHERE Peer-reviewed

    T NARUSHIMA, T GOTO, Y IGUCHI, T HIRAI

    HIGH TEMPERATURE CORROSION OF ADVANCED MATERIALS AND PROTECTIVE COATINGS 345-350 1992

    Publisher: NORTH HOLLAND, ELSEVIER SCIENCE PUBL BV

  256. High-temperature active oxidation of CVD-Si3N4 in ArO2 atmosphere Peer-reviewed

    Takayuki Narushima, Yasutaka Iguchi, Takashi Goto, Toshio Hirai, Yoshio Yokoyama

    Solid State Ionics 53-56 (1) 265-269 1992

    DOI: 10.1016/0167-2738(92)90389-7  

    ISSN:0167-2738

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    Active oxidation of CVD-Si3N4 in ArO2 atmospheres was investigated at temperatures from 1823 to 1923 K. Active oxidation rates increased with increasing oxygen partial pressure, temperature and total gas flow rate. The rate-controlling step for active oxidation is oxygen diffusion through a gaseous boundary layer. The transition from active to passive oxidation was observed at a certain oxygen partial pressure. The transition behavior is discussed using Wagner's model. © 1992.

  257. HIGH-TEMPERATURE ACTIVE OXIDATION OF CHEMICALLY VAPOR-DEPOSITED SILICON-CARBIDE IN AN AR-O-2 ATMOSPHERE Peer-reviewed

    T NARUSHIMA, T GOTO, Y IGUCHI, T HIRAI

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 74 (10) 2583-2586 1991/10

    Publisher: AMER CERAMIC SOC

    DOI: 10.1111/j.1151-2916.1991.tb06803.x  

    ISSN:0002-7820

    More details Close

    Active oxidation behavior of chemically vapor-deposited silicon carbide in an Ar-O2 atmosphere at 0.1 MPa was examined in the temperature range between 1840 and 1923 K. The transition from active oxidation (mass loss) to passive oxidation (mass gain) was observed at certain distinct oxygen partial pressures (P(O2)t). The values of P(O2)t increased with increasing temperature and with decreasing total gas flow rates. This behavior was well explained by Wagner's model and thermodynamic calculations. Active oxidation rates (K(a)) increased with increasing O2 partial pressures and total gas flow rates. The rate-controlling step of the active oxidation was concluded to be O2 diffusion through the gaseous boundary layer.

  258. HIGH-TEMPERATURE OXIDATION OF CHEMICALLY VAPOR-DEPOSITED SILICON-CARBIDE IN WET OXYGEN AT 1823 TO 1923-K Peer-reviewed

    T NARUSHIMA, T GOTO, Y IGUCHI, T HIRAI

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 73 (12) 3580-3584 1990/12

    Publisher: AMER CERAMIC SOC

    DOI: 10.1111/j.1151-2916.1990.tb04261.x  

    ISSN:0002-7820

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    The oxidation of chemically vapor-deposited SiC in wet O2 (water vapor partial pressure = 0.01 MPa, total pressure = 0.1 MPa) was examined using a thermogravimetric technique in the temperature range of 1823 to 1923 K. The oxidation kinetics follow a linear-parabolic relationship over the entire temperature range. The activation energies of linear and parabolic rate constants were 428 and 397 kJ.mol-1, respectively. The results suggested that the rate-controlling step is a chemical reaction at an SiC/SiO2 interface in the linear oxidation regime, and the rate-controlling step is an oxygen diffusion process through the oxide film (cristobalite) in the parabolic oxidation regime.

  259. HIGH-TEMPERATURE PASSIVE OXIDATION OF CHEMICALLY VAPOR-DEPOSITED SILICON-CARBIDE Peer-reviewed

    T NARUSHIMA, T GOTO, T HIRAI

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY 72 (8) 1386-1390 1989/08

    Publisher: AMER CERAMIC SOC

    DOI: 10.1111/j.1151-2916.1989.tb07658.x  

    ISSN:0002-7820

  260. Active to Passive Transition in the Oxidation of CVD-SiC Peer-reviewed

    T. Narushima, T. Goto, T. Hirai

    Proc. the Materials Research Society International Meeting on Advanced Materials 4 295-300 1989/04

Show all ︎Show first 5

Misc. 90

  1. Preparation and evaluation of visible-light-responsive photocatalytic TiO2 layes to provide antibacterial activity on titanium Invited Peer-reviewed

    K. Ueda, T. Narushima and R. Koizumi

    Kinzoku, Materials Science & Technology 94 (3) 233-238 2024/03

  2. Reactions between Ti and light elements Invited

    Takayuki Narushima

    J. Jpn. Inst. Titanium 1 (1) 20-27 2023/08

  3. Recent activities of titanium research in academia Invited

    Takayuki Narushima

    Japan Titanium Society's 70th Anniversary Magazine –Toward a Sustainable World through Maturity and Transformation– 99-115 2023/02

  4. Antibacterial surface treatment of titanium alloys Invited Peer-reviewed

    T. Narushima, K. Ueda, R. Koizumi

    J. Surf. Finish. Soc. Jpn. 72 (11) 616-621 2021/11

    Publisher: The Surface Finishing Society of Japan

    DOI: 10.4139/sfj.72.616  

    ISSN:0915-1869

    eISSN:1884-3409

  5. Antibacterial Functionalization of Ti-based Biomaterials Based on the Understanding of the Inactivation Mechanisms of Bacteria via Photocatalytic Activity of Titanium Oxide: Visible-light Responsive Reaction of Titanium Oxide Coating Invited Peer-reviewed

    Kyosuke Ueda, Takatoshi Ueda, Takayuki Narushima

    Materia Japan 59 (11) 612-617 2020/11/01

    Publisher: Japan Institute of Metals

    DOI: 10.2320/materia.59.612  

    ISSN:1340-2625

    eISSN:1884-5843

  6. Experimental and theoretical oxidation study of Ti–6Al–4V alloys with added Si Invited

    T. Narushima, K. Ueda, R. Sahara, S.K. Bhattacharya

    Titanium Japan 68 (4) 328-335 2020/10

  7. Controlling bio-dissolution of amorphous calcium phosphate and applying antibacterial activity to Ti as a carrier of Ag Invited Peer-reviewed

    K. Ueda, T. Narushima

    J. Jpn. Soc. Biomat. 38 (4) 242-247 2020/10

  8. Recent activities of titanium research and development in Japan Invited Peer-reviewed

    T. Narushima, Y. Sugizaki

    MATEC Web of Conferences 321 01004 2020/10

    DOI: 10.1051/matecconf/202032101004  

  9. Formation of titania coating layer on Ti-Au alloy by thermal oxidation and its antibacterial property through photocatalytic activity under visible-light irradiation Invited Peer-reviewed

    K. Ueda, T. Ueda, T. Narushima

    JCS-Japan 55 (3) 146-149 2020/03

  10. Multifunctionalization through surface treatment of metallic biomaterials Invited

    NARUSHIMA Takayuki

    Chemistry Today 587 51-53 2020/02

  11. Surface treatment of metallic biomaterials Invited Peer-reviewed

    NARUSHIMA Takayuki

    The special steel 68 (5) 45-48 2019/09

  12. Ti-17合金の時効析出に及ぼす酸素濃度の影響

    上田恭介, 福島涼太, 北嶋具教, 成島尚之

    日本金属学会講演概要(CD-ROM) 164th 2019

    ISSN:2433-3093

  13. Special Issue on Latest Research and Development of Structural and Functional Titanium-Based Materials PREFACE

    Takayoshi Nakano, Takayuki Narushima, Takao Hanawa, Masato Ueda, Yoko Yamabe-Mitarai, Tadashi Furuhara, Hideki Hosoda, Mitsuo Niinomi

    MATERIALS TRANSACTIONS 60 (9) 1732-1732 2019

    Publisher: JAPAN INST METALS & MATERIALS

    DOI: 10.2320/matertrans.MPR2019906  

    ISSN:1345-9678

    eISSN:1347-5320

  14. Coatings for improving bone compatibility of titanium Invited Peer-reviewed

    Kyosuke Ueda, Takatoshi Ueda, Naoki Sato, Takayuki Narushima

    J. Surf. Finish. Soc. Jpn. 68 (8) 341-345 2018/08

  15. High-temperature oxidation of titanium and its alloys Invited Peer-reviewed

    T. Narushima

    J. Jpn. Light Metals 68 (7) 354-365 2018/07

  16. Surface treatment of Ti and its alloys for biofunctionalization

    T. Narushima

    Titanium Japan 65 (4) 292-298 2017/10

  17. Ag含有非晶質リン酸カルシウムコーティングによる硬組織代替デバイスへの抗菌性と骨形成能の付与

    上田 恭介, 井上 紅花, 伊藤 甲雄, 小笠原 康悦, 成島 尚之

    日本骨形態計測学会雑誌 27 (1) S140-S140 2017/05

    Publisher: 日本骨形態計測学会

    ISSN:0917-4648

  18. Development of antibacterial biomaterials

    K. Ueda, T. Narushima

    Inflammation & Immunity 25 (2) 110-117 2017/03/01

  19. Transition and Prospect of Biomedical and Healthcare Materials from the Viewpoint of Surface Treatment

    Takayuki Narushima

    Materia Japan 56 (3) 215-219 2017/03/01

    Publisher: The Japan Institute of Metals and Materials

    DOI: 10.2320/materia.56.215  

    ISSN:1340-2625

  20. 電子ビーム積層造形(EBM)した生体用Co-Cr-Mo合金の組織と晶析出物分析

    小泉雄一郎, 魏代修, 山中謙太, 千葉晶彦, 植木洸輔, 上田恭介, 成島尚之

    日本金属学会講演概要(CD-ROM) 160th 2017

    ISSN:2433-3093

  21. Ti-5Al-2Sn-2Zr-4Mo-4Cr(Ti-17)合金の大気中酸化挙動に及ぼすSi添加の影響

    鈴木聡, 上田恭介, BHATTACHARYA S.K., 佐原亮二, 北嶋具教, 成島尚之

    日本金属学会講演概要(CD-ROM) 160th 2017

    ISSN:2433-3093

  22. NiTi and Co-Cr alloys used in biomedical stents

    T. Narushima, Alfirano, K. Ueda

    Proceedings of National Seminar of Metallurgy and Materials IX (SENAMM IX) 7-16 2016/10/11

  23. Titanium and its alloys

    M. Niinomi, M. Ikeda, E. Kobayashi, T. Narushima

    J. Jpn. Inst. Light Metals 66 (8) 468-470 2016/08/22

    Publisher: 軽金属学会

    ISSN:0451-5994

  24. Ti-6Al-4V-xSi(x=0~1mass%)合金の耐酸化性と機械的特性

    前田幸大, 上田恭介, 北嶋具教, 池田亜矢子, 萩原益夫, 佐原亮二, 御手洗容子, 成島尚之

    日本金属学会講演概要(CD-ROM) 159th 2016

    ISSN:2433-3093

  25. Ti-6242S合金の酸化挙動

    池田亜矢子, 北嶋具教, 萩原益夫, 江村聡, 佐原亮二, 成島尚之, 上田恭介

    日本金属学会講演概要(CD-ROM) 159th 2016

    ISSN:2433-3093

  26. Special Issue on Advances in Biomedical Materials Science and Technology PREFACE

    Mitsuo Niinomi, Takao Hanawa, Takayuki Narushima, Takayoshi Nakano, Masahiko Ikeda

    MATERIALS TRANSACTIONS 57 (12) 1985-1985 2016

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MPR2016905  

    ISSN:1345-9678

    eISSN:1347-5320

  27. The role of niobium ions in calcium phosphate invert glasses for bone regeneration

    A. Obata, H. Maeda, K. Ueda, T.Narushima, T. Kasuga

    Phosphorus Research Bulletin 30 30-34 2015/12/31

    Publisher: Japanese Association of Inorganic Phosphorus Chemistry

    DOI: 10.3363/prb.30.3  

    ISSN:0918-4783

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    Abstract: Phosphate invert glasses (PIGs) containing niobium were prepared by a conventional melt-quenching method and the structures and chemical durability of the glasses and osteoblast-like cell responses to them were examined. Raman and solid state <SUP>31</SUP> P NMR spectra of the glasses demonstrated that two types of niobate groups, NbO<SUB>4</SUB> and NbO<SUB>6</SUB> units, were contained in the glasses and prepared to combine to pyrophosphate structure than orthophosphate one. The chemical durability in Tris-HCl solution was increased with the increase in the niobium content in the glasses, since niobium replaced to phosphorus and contributed to the formation of P-O-Nb and Nb-O-Nb bonds, which are stronger than P-O-P bond. The niobium ions released from the glasses enhanced the differentiation and mineralization of the cells, rather than the initial adhesion and proliferation. The upregulation of these cell functions by the niobium ions possessed doze-dependence; the medium containing 1 x 10<SUP>-7</SUP> M of the ions exhibited the highest levels of the cell functions.

  28. 超高齢社会でのQOL向上に貢献するバイオマテリアル研究

    成島尚之

    Kawaijuku Guideline 2015 (11) 68-69 2015/11/15

  29. 金属系バイオマテリアルにおける表面改質

    成島尚之

    メカニカルサーフェス・テック (028) 20-22 2015/10/25

    Publisher: メカニカル・テック社

  30. Titanium and its alloys

    M. Niinomi, M. Ikeda, E. Kobayashi, T. Narushima

    J. Jpn. Inst. Light Metals 65 (8) 377-380 2015/08/01

    Publisher: 軽金属学会

    ISSN:0451-5994

  31. Surface and microstructure control of metallic biomaterials

    Narushima Takayuki

    The journal of the Japanese Society for Dental Materials and Devices 34 (2) 127-127 2015/03/25

    Publisher: The Japanese Society for Dental Materials and Devices (JSDMD)

    ISSN:1884-4421

  32. Osseoconduction by calcium phosphate coating

    K. Ueda, T. Narushima

    Journal of Japanese Society of Bone Morphometry 24 (1) 24-31 2014/01

  33. Surface treatment of titanium using thermal oxidation for biomedical applications

    Takayuki Narushima, Kyosuke Ueda, Shota Sado

    Zairyo to Kankyo/ Corrosion Engineering 63 (5) 295-300 2014

    Publisher: Japan Society of Corrosion Engineering

    DOI: 10.3323/jcorr.63.295  

    ISSN:1881-9664 0917-0480

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    Two-step thermal oxidation of Ti and Ti alloys was proposed for improving their bone compatibility this is a surface-treatment process involving the formation of an anatase-containing TiO2 layer. The photocatalytic activity of the TiO2 layer formed was thus evaluated. The two-step thermal oxidation process consisted of: 1) treatment in a CO atmosphere and 2) treatment in air the anatase fraction in the TiO2 layer could be controlled by changing process parameters. An increase in the anatase fraction resulted in photo-induced superhydrophilicity and an increase in the decomposition rate of methylene blue for the TiO2 layer.

  34. Fabrication of functional surface on metallic biomaterials using ceramic coating

    Takayuki Narushima, Kyosuke Ueda, Shota Sado

    Function & Materials 33 (9) 33-39 2013/09/01

    Publisher: シーエムシー出版

    ISSN:0286-4835

  35. Special Issue on New Functions and Properties of Engineering Materials Created by Designing and Processing II PREFACE

    Mitsuo Niinomi, Tadashi Furuhara, Akihiko Chiba, Takayuki Narushima

    MATERIALS TRANSACTIONS 54 (8) 1241-1241 2013/08

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans.MPR2013904  

    ISSN:1345-9678

    eISSN:1347-5320

  36. Metallurgy of light elements present with titanium

    T. Narushima

    Titanium Japan 61 (2) 126-131 2013/04/01

  37. Precipitates in Biomedical Co-Cr Alloys

    Takayuki Narushima, Shingo Mineta, Yuto Kurihara, Kyosuke Ueda

    JOM 65 (4) 489-504 2013/04

    Publisher: SPRINGER

    DOI: 10.1007/s11837-013-0567-6  

    ISSN:1047-4838

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    Herein, precipitates in biomedical Co-Cr-Mo and Co-Cr-W-Ni alloys are reviewed with a focus on their phase, chemical composition, morphology, and formation/dissolution during heat treatment. The effects of the heat-treatment conditions and the addition of minor alloying elements such as carbon, nitrogen, Si, and Mn on the precipitates are also discussed. Mostly, the precipitates in the alloys are of the sigma-phase, M23X6-type phase, eta-phase (M6X-M12X type), pi-phase (M2T3X type), chi-phase, M7X3-type phase, or M2X-type phase (M and T refer to metallic elements, and X refers to carbon and/or nitrogen); the sigma- and chi-phases are intermetallic compounds, and the others are carbides, nitrides, and carbonitrides. The dissolution of the precipitates during solution treatment is delayed by the formation of the pi-phase at temperatures where partial melting occurs in the alloys. In addition, the stability of the precipitates depends on the content of minor alloying elements. For example, the addition of carbon enhances the formation of M23X6-type and M7X3-type precipitates. Nitrogen stabilizes the M2X-type, eta-phase, and pi-phase precipitates, and Si stabilizes the eta-phase and chi-phase precipitates. The balance between the minor alloying element abundances also affects the constitution of the precipitates in Co-Cr alloys.

  38. The effect of amorphous calcium phosphate films by radiofrequency magnetron sputtering on TNTZ implants on integration with bone

    SHIRAISHI N, NARUSHIMA T, GOTO T, NIINOMI M, SUZUKI O, SASAKI K

    The journal of the Japanese Society for Dental Materials and Devices 31 (5) 385-385 2012/09/25

    Publisher: The Japanese Society for Dental Materials and Devices (JSDMD)

    ISSN:1884-4421

    More details Close

    Ti-29Nb-13Ta-4.6Zr alloy (TNTZ) has excellent advantages as a biomaterial, such as low Young's modulus, low cytotoxicity, and the absence of allergens. However, it is unclear whether TNTZ can achieve sufficient osseointegration as a dental implant. The effectiveness of surface modification of TNTZ implants with amorphous calcium phosphate (ACP) by radiofrequency (RF) magnetron sputtering is also unclear. We investigated the biomechanical behaviors of TNTZ implants in vivo. The results suggest that TNTZ implants can achieve osseointegration similar to that of pure Ti, and that surface modification with ACP by RF magnetron sputtering improves osseointegration.

  39. On the Tohoku branch : History and activities

    NIINOMI Mitsuo, NARUSHIMA Takayuki

    61 (11) 605-606 2011/11/30

    ISSN:0451-5994

  40. Titanium and its alloys

    M. Niinomi, M. Ikeda, T. Narushima

    J. Jpn. Light Metals 61 (11) 673-677 2011/11/01

  41. Research and Development of Metallic Biomaterials in Japan

    T. Narushima

    Proceeding: 4th NATIONAL SEMINAR of METALLURGY and MATERIAL 11-24 2010/07

  42. Special Issue on Low-Cost Reduction Processes, Roles of Low-Cost Elements and Interstitial Elements, and Microstructural Control for Generalization of Titanium Alloys PREFACE

    Mitsuo Niinomi, Takao Hanawa, Masahiko Ikeda, Akihiko Chiba, Tadashi Furuhara, Takayuki Narushima, Koichi Tsuchiya, Satoshi Emura, Takayoshi Nakano, Toshihide Takenaka

    MATERIALS TRANSACTIONS 50 (12) 2703-2703 2009/12

    Publisher: JAPAN INST METALS

    ISSN:1345-9678

    eISSN:1347-5320

  43. New Market Opportunity (IV): Biomedical Application

    Takayuki Narushima

    The 61st Shiraishi Memorial Lecture, Strategies for the Highly Efficient Use of Titanium toward the Ubiquitous Ages and Titanium's New Market Opportunities 125-142 2009/10/09

    Publisher: The Iron and Steel Institute of Japan

  44. Special Issue on New Functions and Properties of Engineering Materials Created by Designing and Processing PREFACE

    Masahiko Morinaga, Mitsuo Niinomi, Tadashi Furuhara, Akihiko Chiba, Takayuki Narushima

    MATERIALS TRANSACTIONS 50 (7) 1612-1612 2009/07

    Publisher: JAPAN INST METALS

    ISSN:1345-9678

    eISSN:1347-5320

  45. S109 Fabrication and Evaluation of Calcium Phosphate Coating Films on Blast-treated Ti-6Al-4V Substrate

    NARUSHIMA Takayuki, UEDA Kyosuke, GOTO Takashi, KURIHARA Jun, NAKAGAWA Hironobu, KAWAMURA Hiroshi

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2008 (0) 331-332 2009

    Publisher: 一般社団法人 日本機械学会

  46. S111 Effect of microstructure for apatite formation on Ca-P-O films prepared by CVD

    SATO Mitsutaka, TU Rong, GOTO Takashi, UEDA Kyosuke, NARUSHIMA Takayuki

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2008 (0) 335-336 2009

    Publisher: 一般社団法人 日本機械学会

  47. J0401-2-3 Evaluation of Calcium Phosphate Coating Film on Titanium Substrate

    UEDA Kyosuke, KAWASAKI Yuuki, NARUSHIMA Takayuki, GOTO Takashi, KURIHARA Jun, KAWAMURA Hiroshi

    The proceedings of the JSME annual meeting 2009 (0) 271-272 2009

    Publisher: 一般社団法人 日本機械学会

    DOI: 10.1299/jsmemecjo.2009.6.0_271  

    More details Close

    Amorphous calcium phosphate (ACP), oxyapatite (Ca_&lt;10&gt;(PO_4)_6O, OAp), heat-treated OAp (OAp-AIR) and OAp/OAp-AIR double layer (D-layer) coating films were fabricated on the surface of the titanium substrates using RF magnetron sputtering. The cross sectional observation before and after the implantation, bonding strength between coating film and substrates and removal torques from femur of Japanese white rabbits were examined. The bonding strength between coating films and substrates were more than 50 MPa, and removal torque of coated implants from the femur of Japanese white rabbits were greater than that of uncoated one. After the implantation of ACP coating film, the coating would be dissolved into the body and it caused the high biocompatibility of bone.

  48. Deoxidation of NiTi Alloy Melts Using Metallic Barium (vol 49, pg 289, 2008)

    Susumu Miyamoto, Masatoshi Watanabe, Takayuki Narushima, Yasutaka Iguchi

    MATERIALS TRANSACTIONS 49 (12) 2922-2922 2008/12

    Publisher: JAPAN INST METALS

    ISSN:1345-9678

    eISSN:1347-5320

  49. Strategy for ubiquitous titanium alloys

    Mitsuo Niinomi, Takao Hanawa, Masahiko Ikeda, Akihiko Chiba, Tadashi Furuhara, Takayuki Narushima, Koichi Tsuchiya, Satoshi Emura, Takayoshi Nakano, Toshihide Takenaka

    Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals 72 (12) 915 2008/12

    DOI: 10.2320/jinstmet.72.915  

    ISSN:0021-4876

  50. Surface modification for improving biocompatibility of titanium materials with bone

    Takayuki Narushima

    Keikinzoku/Journal of Japan Institute of Light Metals 58 (11) 577-582 2008/11

    DOI: 10.2464/jilm.58.577  

    ISSN:0451-5994

  51. レーザーCVD法により合成したリン酸カルシウム膜のアパタイト形成能

    佐藤充孝, 塗溶, 後藤孝, 上田恭介, 成島尚之

    日本金属学会講演概要 142nd 2008

    ISSN:1342-5730

  52. レーザーCVD法により合成したHAp膜上へのアパタイト形成の結晶配向依存性

    佐藤充孝, 塗溶, 後藤孝, 上田恭介, 成島尚之

    日本金属学会講演概要 143rd 2008

    ISSN:1342-5730

  53. In vivo and vitro evaluation of titanium materials coated with calcium phosphate film

    NARUSHIMA Takayuki

    113 59-60 2007/10/10

  54. Surface treatment: Surface morphology and composition/phase control in metallic biomaterials

    T.Narushima

    J.Jpn.Soc.Biomat. 25 (3) 252-260 2007/08

  55. Surface modification of metals for medical applications

    NARUSHIMA Takayuki

    Journal of Japanese Society for Biomaterials 25 (4) 252-260 2007/07/15

    Publisher: 日本バイオマテリアル学会

    ISSN:1347-7080

  56. PREFACE

    HOSODA Hideki, NAKANO Takayoshi, NARUSHIMA Takayuki, HANAWA Takao, NIINOMI Mitsuo, MIYAZAKI Shuichi

    48 (3) 277-277 2007/03/01

    ISSN:1345-9678

  57. Special Issue on smart and harmonic biomaterials

    Hideki Hosoda, Takayoshi Nakano, Takayuki Narushima, Takao Hanawa, Mitsuo Niinomi, Shuichi Miyazaki

    MATERIALS TRANSACTIONS 48 (3) 277-277 2007/03

    Publisher: JAPAN INST METALS

    ISSN:1345-9678

    eISSN:1347-5320

  58. Titanium and its alloys for medical applications

    T.Narushima

    Kinzoku, Materials Science & Technology 77 (2) 122-127 2007/02

  59. MOCVD法によるCa-Ti-OおよびCa-P-O傾斜機能バイオセラミックス膜の合成

    佐藤充孝, 塗溶, 後藤孝, 上田恭介, 成島尚之

    粉体粉末冶金協会講演概要集 2007 2007

  60. MOCVD法により合成したCa-P-O膜上への擬似体液中におけるアパタイト形成

    佐藤充孝, TU R., 後藤孝, 上田恭介, 成島尚之

    セラミックス基礎科学討論会講演要旨集 45th 2007

  61. MOCVD法により合成したCa-P-O膜の擬似体液中におけるHAp形成

    佐藤充孝, 塗溶, 後藤孝, 上田恭介, 成島尚之

    日本金属学会講演概要 140th 2007

    ISSN:1342-5730

  62. Effect of oxygen partial pressure on electrical conductivity of Ca-Ru-O compounds prepared by spark plasma sintering

    Mitsutaka Sato, Rong Tu, Takashi Goto, Kyosuke Ueda, Takayuki Narushima

    Materials Science Forum 561-565 (0) 595-598 2007

  63. Elemental analysis of culture medium and macrophage RAW264 phagocytizing Ti ions by PIXE method

    TAIRA M., SASAKI K., SAITOH S., NEZU T., ARAKI Y., NARUSHIMA T.

    Journal of the Japanese Society for Dental Materials and Devices 25 (2) 181-181 2006/04/05

    Publisher: The Japanese Society for Dental Materials and Devices (JSDMD)

    ISSN:0286-5858

  64. ハーモニックバイオマテリアル-界面制御型生体調和材料創製の可能性-MOCVD法により合成したCaTiO<sub>3</sub>膜の擬似体液中におけるHAp形成

    佐藤充孝, 塗溶, 後藤孝, 上田恭介, 成島尚之

    日本金属学会講演概要 138th 2006

    ISSN:1342-5730

  65. Growth of HAp on the CVD CaTiO<sub>3</sub> film in Hank's solution

    Tu Rong, Sato Mitsutaka, Goto Takashi, Ueda Kyosuke, Narushima Takayuki

    Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan 2006 (0) 591-591 2006

    Publisher: 公益社団法人 日本セラミックス協会

    More details Close

    縦型コールドウォール式CVD装置を用い、Ca(dpm)&lt;sub&gt;2&lt;/sub&gt;およびTi(OiPr)&lt;sub&gt;2&lt;/sub&gt;(dpm)&lt;sub&gt;2&lt;/sub&gt;によりCaTiO&lt;sub&gt;3&lt;/sub&gt;膜を作製した。基板温度が973、1073 Kでは原料モル比が約1のとき、CaTiO3単一相が得られたが、873 KではCaTiO&lt;sub&gt;3&lt;/sub&gt;とCaOの混合相が得られた。膜の微細組織波、基板温度の上昇に伴いCaTiO&lt;sub&gt;3&lt;/sub&gt;膜の断面組織は緻密構造から柱状晶へと変化した。成膜速度は基板温度の上昇および反応室内圧力の減少とともに増大し、基板温度1073 K、反応室内圧力0.4 kPaでは最大であった。ハンクス溶液中におけるHApの生成を調べた。

  66. 特集「QOL向上のための材料技術」

    新家光雄, 塙隆夫, 千葉晶彦, 成島尚之, 福井壽男, 岡崎義光, 池田勝彦

    日本金属学会誌 70 (4) 259-259 2006

  67. Titanium and its alloys as biomaterials (J.Jpn.Inst.Light Metals)

    T. Narushima

    J.Jpn.Inst.Light Metals 55 (11) 561-565 2005/11

    DOI: 10.2464/jilm.55.561  

  68. Effect of titanium ion on cell viability of macrophage-like RAW264 cells

    TAIRA M., SASAKI K., SAITOH S., NEZU T., ARAKI Y., NARUSHIMA T.

    Journal of the Japanese Society for Dental Materials and Devices 24 (5) 349-349 2005/09/05

    Publisher: The Japanese Society for Dental Materials and Devices (JSDMD)

    ISSN:0286-5858

  69. Special Issue on Medical, Healthcare, Sport and Leisure Materials - Preface

    M Niinomi, T Hanawa, Y Okazaki, M Ikeda, A Chiba, T Narushima, H Fukui

    MATERIALS TRANSACTIONS 46 (7) 1514-1514 2005/07

    Publisher: JAPAN INST METALS

    ISSN:1345-9678

    eISSN:1347-5320

  70. Metallic biomaterials: Titanium and its alloys

    T.Narushima

    J.Jpn.Soc.Biomat. 23 (2) 86-95 2005/04

  71. Japanese research and development on metallic biomedical, dental, and healthcare materials

    M Niinomi, T Hanawa, T Narushima

    JOM 57 (4) 18-24 2005/04

    Publisher: SPRINGER

    DOI: 10.1007/s11837-005-0076-3  

    ISSN:1047-4838

    eISSN:1543-1851

    More details Close

    There is considerable demand for metallic materials for use in medical and dental devices. Metals and alloys are widely used as biomedical materials and are indispensable in the medical field. In dentistry, metal is used for restorations, orthodontic wires, and dental implants. This article describes R&D on metallic biomaterials primarily conducted by the members of the Japan Institute of Metals.

  72. Hydrothermal synthesis of zeolite A from iron and steelmaking slag and crystalline Al_2O_3

    SUGANO Yoshiyuki

    18 (1) 205-205 2005/03/01

    ISSN:0914-6628

  73. Effects of the Heating Temperature and Time on β Grain Growth in α+β Type Titanium Alloy containing a Small Amount of Yttrium

    HOTTA Satoshi

    18 (3) 690-690 2005/03/01

    ISSN:0914-6628

  74. Effect of Y_2O_3 precipitates on refinement of β grain size and β grain growth behavior in titanium alloy

    HOTTA Satoshi

    18 (3) P33 2005/03/01

    ISSN:0914-6628

  75. Preface of Special Issue on Medical Healthcare, Sport and Lesure Materials

    M. Niinomi, T. Hanawa, Y. Okazaki, M. Ikeda, A. Chiba, T. Narushima, H. Fukui

    Mat. Trans. 46 (7) 0 2005

  76. Heat treating characteristics of newly developed α+β titanium alloy with the ultra fine microstructure for implant use

    HIRANO Takahiro, NARUSHIMA Takayuki, IGUCHI Yasutaka, OUCHI Chiaki

    106 181-182 2004/05/18

  77. Effect of dynamic recrystallization of austenite on micro segregation in a strand cast 9%Ni steel

    HOTTA Satoshi

    17 (1) 159-159 2004/03/01

    ISSN:0914-6628

  78. Hydrothermal synthesis of zeolite-materials from iron and steel making slag

    NARUSHIMA Takayuki

    17 (1) 89-89 2004/03/01

    ISSN:0914-6628

  79. Refinement of β grain size due to TiB or Y_2O_3 precipitates in PM titanium alloy

    YAMAMOTO Naoki

    16 (6) 1482-1482 2003/09/01

    ISSN:0914-6628

  80. Effect on microalloy elements on austenitic grain growth behavior after dynamically recrystallization in as-cast HSLA steels

    FUJITA Noriki

    15 (6) 1152-1152 2002/09/01

    ISSN:0914-6628

  81. Grain refinement of as-cast austenitic microstructure due to dynamic recrystallization and subsequent grain growth behavior in steels

    FUJITA Noriki

    15 (3) 615-615 2002/03/01

    ISSN:0914-6628

  82. Refinement of austenitic gain size by precipitaed particles or dynamic recrystallization in as-casted

    OUCHI Chiaki

    14 (6) 1151-1154 2001/09/01

    ISSN:0914-6628

  83. Stainless Steel Electrode for Functional Electrical Stimulation Based on Ultra Clean Refining Processes

    Y.Iguchi, T.Narushima, N.Hoshimiya, Y.Handa

    Bull.ISIJ, 4 (11) 737-740 1999/11

  84. Hydration of Lime-related Materials

    NARUSHIMA Takayuki

    12 (4) 826-826 1999/09/01

    ISSN:0914-6628

  85. Hydration Mechanisms of Steelmaking Slag

    IZUMI Chihiro

    11 (4) 775-775 1998/09/01

    ISSN:0914-6628

  86. <記事>(4) 溶融シリコン中の不純物元素の物理化学的挙動(主題 : 素材・材料プロセスに係わる物性と評価)(素材工学研究所第 6 回研究懇談会)(素材工学研究会記事)

    井口 泰孝, 成島 尚之, 東北大学大学院工学研究科, 東北大学大学院工学研究科

    東北大学素材工学研究所彙報 = Bulletin of the Institute for Advanced Materials Processing, Tohoku University 53 (1) 138-139 1998/03/27

    ISSN:0919-4827

  87. High-temperature oxidation of silicon carbide and silicon nitride

    T Narushima, T Goto, T Hirai, Y Iguchi

    MATERIALS TRANSACTIONS JIM 38 (10) 821-835 1997/10

    Publisher: JAPAN INST METALS

    DOI: 10.2320/matertrans1989.38.821  

    ISSN:0916-1821

    More details Close

    Oxidation behavior of silicon-based ceramics such as SiC and Si3N4 at high temperatures is important for their practical applications to structural or electronic materials. In the present paper two kinds of oxidation (passive and active) and active-to-passive transition of silicon-based ceramics were discussed thermodynamically, and the rate constants of passive/active oxidation and active-to-passive transition oxygen potentials for SiC and Si3N4 were reviewed. Passive and active oxidation behavior depended on the microstructure of oxide films and SiO gas pressure on silicon-based ceramics, respectively. Wagner model, volatility diagram and solgasmix-based calculation were used to estimate the active-to-passive transition.

  88. 東北大学工学部金属物理化学講座・研究紹介

    井口 泰孝, 成島 尚之, 渡辺 雅俊

    資源・素材 1996 (1) 104-104 1996/10/21

    ISSN:0919-7915

  89. 太陽電池用シリコン製造プロセスにおける軽元素不純物の挙動に関する熱力学的研究

    井口 泰孝, 成島 尚之, 簗場 康司

    資源・素材 1996 (6) 12-12 1996/10/01

    ISSN:0919-7915

  90. 口腔内児童骨炎長期の開発:ビーグル犬下顎骨への適用

    勝部朝之, 成島尚之, 中野貴由, 馬越佑吉, 佐々木具文, 伊藤秀美, 古屋泰文, 川村 仁

    日本実験力学学会論文集 (6月2日) 58-61 1994

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Books and Other Publications 20

  1. Fundamentals and Applications of Titanium

    M. Niinomi, M. Ikeda, T. Narushima, T. Nakano, H. Hosoda

    2023/03

    ISBN: 9784753651122

  2. 製品利用に向けたバイオマテリアル開発の基本事項と注意点―材料の特徴・材料 劣化・表面解析・安全性試験・ニーズ収集―

    上田恭介, 成島尚之

    情報機構 2022/06

    ISBN: 9784865022360

  3. Phosphate and Borate Bioactive Glasses

    K. Ueda, T. Narushima

    Royal Society of Chemistry 2022

  4. チタンの準安定相・析出相研究部会報告書

    T. Narushima, K. Ueda, Y. Hirose

    The Japan Institute of Light Metals 2020/10

  5. Metals for biomedical devices, Second Edition

    NARUSHIMA Takayuki

    Woodhead Publishing 2019/08

  6. Addition of Biocompatibility to Inorganic/Organic Materials by Surface Treatment and Modification

    NARUSHIMA Takayuki

    CMC Publishing Co.,Ltd. 2019/01

  7. Biomaterials: Fundamentals and Applications

    T. Narushima

    東京化学同人 2016/02/20

  8. Dental Restorative Materials and Regenerative Medicine

    T. Narushima, K. Ueda, T. Ueda, S. Sada

    CMC Pub. Co., Ltd 2015/08/25

  9. Advances in Metallic Biomaterials: Processing and Applications

    M. Hirohashi, K. Ueda, T. Wada, T. Narushima, H. Kato

    Springer 2015/06/27

    ISBN: 9783662468418

  10. Advances in Metallic Biomaterials: Tissues, Materials and Biological Reactions

    T. Narushima, K. Ueda, Alfirano

    Springer 2015/06/27

    ISBN: 9783662468357

  11. The advanced Research of Biomaterials

    Takayuki Narushima, Takayoshi Nakano

    Japan Institute of Metals 2014/10/31

  12. For future artificial joint

    T. Narushima

    NIHON IGAKUKAN 2013/07/01

  13. Technological Advancements in Biomedicine for Healthcare Applications

    T. Narushima, K. Ueda

    IGI Global 2012/09/30

  14. Biological and Biomedical Coatings Handbook: Processing and Characterization (Advances in Materials Science and Engineering)

    T. Goto, T. Narushima, K. Ueda

    CRC Press 2011/04

  15. Fundamentals of biomaterials for interdisciplinary integration

    T. Narushima

    NIHON IGAKUKAN 2010/11/25

  16. Metals for biomedical devices

    Takayuki Narushima

    Woodhead Publishing Limited 2010/04

  17. Forming and Microstructure of Metals

    Takayuki Narushima

    Kyoritsu Shuppan Co., Ltd. 2010/03/25

  18. Metals for Medicine

    T.Narushima

    Japan Institute of Metals 2010/03

  19. Basic Materials Science, Manufacturing and Newly Advanced Technologies of Titanium and its Alloys

    T. Narushima

    シーエムシー出版 2009/08

  20. 実験 材料科学 ニューマテリアル開発への基礎

    内田老鶴圃, 東北大学工学部マテリアル, 開発系学生実験委員会, 編

    1996/09/15

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Presentations 105

  1. Surface and microstructure control of metallic biomaterials Invited

    T. Narushima

    Yukawa Memorial Lecture, Tohoku Branch. The Iron and Steel Institute of Japan 2023/12/03

  2. Recent trends in tanium R&D in Japan

    T. Narushima

    Japan Institute of Titanium 2023 Meeting (3rd) 2023/11/02

  3. Advancements of Ti research and development in Japan Invited

    T. Narushima

    2023 Fall Conference of the Korean Institute of Metals and Materials 2023/10/26

  4. Recent Activities of Titanium Research and Development in Japan Invited

    T. Narushima

    Titanium Technology Class 2023/08/24

  5. Recent Research and Development Activities on Titanium in Japan Invited

    T. Narushima, T. Hirose

    The 15th World Conference of Titanium (Ti-2023) 2023/06/12

  6. Antibacterial Functionalization of Titanium Surface Using Photocatalytic Activity of TiO2 Films Invited

    Takayuki Narushima

    Japan Institute of Metals 2022 Autumn Meeting (171st) 2022/09/21

  7. Antibacterial functionalization by surface treatment of titanium Invited

    T. Narushima

    2021 Joint Workshop of Institute of Materials Research, Tohoku University and Tohoku Block Meeting of the Japanese Society for Biomaterials 2021/09/29

  8. Thermodynamics of titanium and its alloys from the viewpoint of high temperature oxidation reaction Invited

    Takayuki Narushima

    Jointly hosted by the Japanese Institute of Titanium and the Industry-Academia Collaboration Committee of the Japan Titanium Society, the first web-based educational lecture on the fundamentals and applications of titanium in 2021. 2021/06/18

  9. Oxygen Removal from Ti melts using plasma Invited

    Takayuki Narushima

    The 8th Research Exchange Meeting for Titanium Researchers and Engineers 2021/03/04

  10. 金属系バイオマテリアルの表面・組織制御

    成島尚之

    東北大学材料科学ウェビナー 2020/09/07

  11. Thermodynamics in Materials Science and Engineering Invited

    2020/01/29

  12. 日本におけるチタン研究の動向 Invited

    成島尚之

    東邦チタニウム講演会 2020/01/22

  13. 金属チタン研究の最先端 Invited

    NARUSHIMA Takayuki

    日本機械学会2019年度年次大会 2019/09/09

  14. Preparation of bioceramic coatings on Ti and its alloys by dry processes and their antibacterial activity International-presentation Invited

    NARUSHIMA Takayuki

    the 10th Pacific Rim International Conference on Advance Materials and Processing (PRICM-10) 2019/08/21

  15. Recent Activities of Titanium Research and Development in Japan International-presentation Invited

    T. Narushima, Y. Sugizaki

    The 14th World Conference of Titanium (Ti-2019) 2019/06/11

  16. 日本チタン研究の最先端

    成島 尚之

    一般社団法人日本チタン協会, 2019年度通常総会記念講演会 2019/05/28

  17. 水素プラズマを利用したチタン融体からの酸素除去の可能性

    成島 尚之

    本金属学会チタン製造プロセスと材料機能研究会第5回講演会 2019/01/25

  18. Formation and Antibacterial Activity of TiO2 Layers on Ti-Au Alloys International-presentation Invited

    Takayuki Narushima, Kyosuke Ueda, Takatoshi Ueda, Naoki Sato

    15th International Symposium on Functionally Graded Materials 2018/08/07

  19. Antibacterial activity of TiO2 layers formed on Ti-Au alloys by thermal oxidation International-presentation Invited

    T. Narushima, T. Ueda, N. Sato, K. Ueda, K. Ito, K. Ogasawara, H. Kanetaka

    Finland-Japan Workshop: The next generation medical engineering in biomaterials, Joint with 3rd Bone and Biomaterials Workshop 2018/06/20

  20. Tiの高温酸化に及ぼすSiの影響に関する実験的・計算材料学的研究

    成島尚之, 上田恭介, 鈴木聡, 佐原亮二, Somesh Kr. Bhattacharya

    本金属学会チタン製造プロセスと材料機能研究会第4回講演会 2018/01/26

  21. ドライプロセスによる 金属系バイオマテリアル表面処理 の現状と展望

    成島尚之, 上田恭介, 鈴木聡, 佐原亮二, Somesh Kr. Bhattacharya

    日本金属学会2017秋期(第161回)講演大会 2017/09/06

  22. バイオマテリアルーからだの中で活躍する材料ー

    成島 尚之

    東北大学 工学部・工学研究科技術一般研修 2017/08/01

  23. ステント用金属系バイオマテリアルの機械的特性

    成島尚之, 上田恭介, 鈴木聡, 佐原亮二, Somesh Kr. Bhattacharya

    SMAシンポジウム2016 2016/11/11

  24. NiTi and Co-Cr alloys used in biomedical stents International-presentation

    T. Narushima, Alfirano, K. Ueda

    National Seminar of Metallurgy and Materials IX (SENAMM IX) 2016/10/11

  25. Formation and evaluation of TiO2 layers on Ti alloys prepared by thermal oxidation

    成島 尚之

    4th AMED-CNPq project seminar and meeting 2016/09/05

  26. Surface modification of Ti using bio-ceramic coating International-presentation

    Takayuki Narushima, Takatoshi Ueda, Shota Sado, Kyosuke Ueda

    2nd Bone and Biomaterials Workshop Hotelli Inari, Inarintie 40, 99870 Inari, Finland 2016/08/07

  27. Biomaterials, Smart Materials and Structures International-presentation

    Takayuki Narushima

    The Ninth Pacific Rim International Conference on Advanced Materials and Processing (PRICM 9) 2016/08/01

  28. Precipitates and mechanical properties of metallic biomaterials International-presentation

    Takayuki Narushim

    Thermec’ 16, Intl’ Conf. on Processing & Manufacturing of Advanced Materials 2016/05/30

  29. ドライプロセスを用いたチタンの生体用表面改質

    成島尚之

    軽金属学会第130回春期大会 2016/05/28

  30. Fatigue properties of NiTi wires used in biomedical applications International-presentation

    Takayuki Narushima

    The 6th International Symposium for Interface Oral Health Science 2016/01/18

  31. レアメタル一次資源部門

    成島 尚之

    東北大学レアメタル・グリーンイノベーション研究開発センター 第一回フォーラム 2015/12/22

  32. 生体材料としてのチタン

    成島 尚之

    仙台青葉工業クラブ第42回講演会 2015/10/18

  33. 金属系バイオマテリアルと軽元素との反応

    成島尚之

    東北大学金属材料研究所共同研究ワークショップ、日本バイオマテリアル学会東北地域講演会 2015/09/07

  34. Formation and evaluation of thermally-oxidized titania layer on Ti and Ti alloys International-presentation

    Takayuki Narushima, Takatoshi Ueda, Shota Sado, Kyosuke Ueda

    Ti-2015: The 13th World Conference on Titanium 2015/08/16

  35. 金属系バイオマテリアルの表面・組織制御

    成島尚之

    第65回日本歯科理工学会学術講演会 2015/04/16

  36. 生体用NiTiの晶析出物と疲労特性

    成島 尚之, 原 健治, 上田 恭介, 山下 史祥, 石川 浩司

    東北大学金属材料研究所共同研究ワークショップ、日本バイオマテリアル学会東北地域講演会 2014/10/06

  37. 二段階熱酸化プロセスを利用した生体用チタンの表面処理

    成島尚之, 佐渡翔太, 近藤なつ美, 上田恭介

    第181回腐食防食シンポジウム 2014/09/16

  38. Reaction between light elements and metallic biomaterials: thermal oxidation and precipitation International-presentation

    T. Narushima

    156th IBB Seminar, JST-CNPq Project 2014/09/16

  39. 金属系バイオマテリアルの軽元素メタラジー

    成島尚之

    北海道大学工学研究院材料科学専攻 第51回マテリアルセミナー 2014/05/27

  40. Photocatalytic evaluation of TiO2 layer formed on titanium by thermal oxidation International-presentation

    T. Narushima, S. Sado, K. Ueda, M. Kawano, K. Ogasawara

    Innovative Research for Biosis-Abiosis Intelligent Interface Symposium 2014/01/20

  41. Formation of anatase layer using two-step thermal oxidation and its evaluation International-presentation

    T. Narushima, K. Ueda, S. Sado

    5th International Symposium on Advanced Ceramics (ISAC-5) 2013/12/09

  42. Precipitates and properties of biomedical Co-Cr-W-Ni alloys International-presentation

    T. Narushima, Y. Kurihara, K. Ueda

    International Conference on Processing & Manufacturing of Advanced Materials (THERMEC’ 2013) 2013/12/02

  43. 金属材料のセラミックスコーティング

    成島尚之, 上田恭介

    学振第176委員会(加工プロセスによる材料機能発現)第24回研究会 2013/11/01

  44. Surface treatments of titanium using thermal oxidation International-presentation

    T. Narushima, K. Ueda, S. Sado

    The Eighth Pacific Rim International Conference on Advanced Materials and Processing (PRICM-8) 2013/08/04

  45. チタン系融体の脱酸と析出物への影響

    成島尚之, 上田恭介, 伊藤大介, 西脇成彦

    日本金属学会機能性チタン合金研究会 2013/01/28

  46. ドライプロセスによるバイオセラミックス被覆

    成島尚之

    日本バイオマテリアル学会シンポジウム2012 2012/11/26

  47. Bioceramic Coating on Titanium Using Dry Process International-presentation

    T. Narushima

    The 5th International Symposium on Designing, Processing and Properties of Advanced Engineering Materials ISAEM-2012 2012/11/05

  48. Precipitates in biomedical Co-Cr-Mo alloys International-presentation

    T. Narushima

    Korea-Japan Joint Work Shop on Biomaterials 2012/09/25

  49. 生体用Co-Cr-Mo合金における晶析出挙動

    成島尚之

    日本金属学会 2012年秋季(第151回)大会 公募シンポジウム「体用Co-Cr合金研究の現状と将来展望」 2012/09/17

  50. 熱酸化法によるチタン表面へのアナターゼ形成と評価

    成島尚之

    東北大学金属材料研究所共同研究ワークショップ、日本バイオマテリアル学会東北地域講演会 2012/09/03

  51. Precipitation in biomedical Co-Cr and NiTi alloys International-presentation

    T. Narushima

    The Japan-Finland Joint Workshop on Future Implant, Research Seminar in Oulu 2012/08/08

  52. Surface modification of titanium using dry process International-presentation

    T. Narushima

    The Japan-Finland Joint Workshop on Future Implant, Research Seminar in Helsinki 2012/08/06

  53. 金属系生体材料における軽元素メタラジー

    成島尚之

    東北大学学際科学国際高等研究センター 第48回インフォーマルセミナー 2012/02/24

  54. Precipitates in biomedical Co-Cr-Mo and NiTi alloys International-presentation

    T. Narushima

    Workshop on a foreign experts academic exchange project 2011/11/02

  55. Fabrication and Evaluation of Amorphous Calcium Phosphate Film on Titanium International-presentation

    T. Narushima, K. Ueda, T. Goto, N. Nishiwaki, S. Yokota, H. Kawamura

    Workshop on Materials Science in Tianjin University Day 2011/10/11

  56. 金属系バイオマテリアル中の析出相

    成島尚之

    東北大学金属材料研究所共同研究ワークショップ、日本バイオマテリアル学会東北地域講演会 2011/09/29

  57. Deoxidation of NiTi alloys using metallic barium and their microstructures International-presentation

    T. Narushima, D. Ito, K. Ueda

    The 12th World Conference on Titanium 2011/06/20

  58. Precipitates in Metallic Biomaterials International-presentation

    T. Narushima

    The 4th International Symposium for Interface Oral Health Science 2011/03/07

  59. ドライプロセスを利用したチタン系材料の表面・バルク処理

    成島尚之

    日本鉄鋼協会・日本金属学会関西支部 材料開発研究会 平成22年度第4回研究会 2011/01/20

  60. Surface Modification of Titanium for Biomedical Applications International-presentation

    Takayuki Narushim

    The 1st Joint Workshop on Advanced Materials Research & Application, Dalian University of Technology - Tohoku University 2010/11/03

  61. 生体用Co-Cr-Mo合金中の析出物形成および溶解挙動

    成島尚之, 峯田真悟, Alfirano, 難波茂信, 米田隆志, 上田恭介

    東北大学金属材料研究所共同研究ワークショップ、日本バイオマテリアル学会東北地域講演会、金属系バイオマテリアルの力学的および生物学的生体機能性の付与-骨機能再建・再生マテリアルの創製に向けて- 2010/08/30

  62. Calcium Phosphate Coating on Titanium Using Dry Process International-presentation

    Takayuki Narushima

    The Seventh Pacific Rim International Conference on Advanced Materials and Processing (PRICM7) 2010/08/01

  63. Research and Development of Metallic Biomaterials in Japan International-presentation

    Takayuki Narushima

    Special Seminar in Research Center for Metallurgy 2010/07/16

  64. Research and Development of Metallic Biomaterials in Japan International-presentation

    Takayuki Narushima

    4th National Seminar of Metallurgy and Material 2010/07/14

  65. Surface treatment of titanium by gas processes International-presentation

    Takayuki Narushima

    International Cooperation between KITECH and Tohoku University 2010/02/25

  66. 金属系生体材料の高機能化

    成島尚之

    MAST21 第14回フォーラム 2009/11/27

  67. ガス法によるチタン材料の表面硬化処理

    成島尚之

    日本金属学会 機能性チタン合金研究会第2回講演会 2009/11/20

  68. Surface modification of titanium by dry process for biomedical applications International-presentation

    T. Narushima, K. Ueda, T. Goto

    the 9th International Symposium on Biomaterials 2009/10/29

  69. ユビキタス時代に向けたチタンの元素戦略と新しい用途展開 『新しい用途展開(Ⅳ) 生体・医療用途』

    成島尚之

    第61回白石記念講座 2009/10/09

  70. 骨/リン酸カルシウムコーティング膜/チタンインプラント界面の力学特性

    成島尚之, 上田恭介, 後藤孝

    日本金属学会 2009年秋季(第145回)大会 公募シンポジウム「力学的生体適合性」 2009/09/15

  71. Surface modification of titanium by pack cementation process for biomedical applications International-presentation

    Takayuki NARUSHIMA

    The third International Conference on Processing, Manufacturing of Advanced Materials (ICAM-2009) 2009/07/08

  72. Fabrication and Evaluation of Calcium Phosphate Films Coated on Blast-treated Ti-6Al-4V Substrate International-presentation

    Takayuki NARUSHIMA

    International Conference on Materials for Advanced Technologies (ICMAT 2009) 2009/06/28

  73. 金属系生体材料製造プロセスにおける軽元素の挙動

    成島尚之

    第126回特殊鋼部会大会 2009/06/04

  74. Calcium phosphate coating on titanium by RF magnetron sputtering International-presentation

    KIM-JIM Symposium 2009/03/29

  75. 酸素を利用したチタンの表面・組織制御

    成島尚之

    第34回 材質制御研究会―歯科材料を中心した生体材料開発の最前線― 2008/12/26

  76. In vivo and in vitro evaluation of amorphous calcium phosphate films coated on titanium implants by RF magnetron sputtering International-presentation

    T. Narushima

    4th International Symposium on Designing,Processing and Properties of Advanced Engineering Materials (ISAEM-2008) 2008/11/18

  77. Calcium phosphate formation on NaOH-treated titanium in simulated body fluids International-presentation

    Takayuki Narushima, Shuntaro Watanabe, Kenichi Kato, Kyosuke Ueda

    the 2008 Fall Annual Meeting of the KIM, 2008 Fall Conference 2008/10/23

  78. Amorphous Calcium Phosphate Thin Film Coated on Titanium Implant by RF Magnetron Sputtering International-presentation

    T. Narushima

    2nd PNU – IMR Joint Workshop on Advanced and Bio Materials 2008/06/06

  79. リン酸カルシウムコーティングを施したチタン材料の生体内外評価

    成島尚之

    社団法人軽金属学会第113回大会 2007/11/10

  80. In vivo and In vitro Evaluation of Calcium Phosphate Coating Films on Blast-treated Titanium Substrate International-presentation

    T. Narushima, K.Ueda, T.Goto, H.Kawamura, T.Katsube

    Symposium on the Nano Particles and Highly-functional Interface Science 2007/08/09

  81. Fatigue Properties of Titanium Wires for Medical Applications International-presentation

    K.Ueda, T.Kinami, H.Kimura, C.Ouchi, Y.Iguchi

    The 11th World Conference on Titanium 2007/06/03

  82. Calcium Phosphate Coating on Titanium by RF Magnetron Sputtering for Medical Applications International-presentation

    T. Narushima

    The joint symposium on advanced materials between Pusan nationals university and Tohoku university 2007/05/07

  83. チタン上に作製したリン酸カルシウムスパッタリング膜の生体内外評価

    成島尚之

    東北大学金属材料研究所共同研究ワークショップ 2006/12/13

  84. Evaluation of Calcium Phosphate Coating Films on Titanium Fabricated Using RF Magnetron Sputtering International-presentation

    T. Narushima, K. Ueda, T. Goto, M. Taira, T. Katsube

    the 4th Korea-China Symposium on Biomaterials and Nano-bio Technology 2006/10/19

  85. Evaluation of RF-magnetron-sputtered calcium phosphate films on titanium for implant applications International-presentation

    T. Narushima

    The 2nd. Korean-Japan joint workshop on biomedical materials 2006/10/09

  86. Calcium Phosphate Coating on Titanium by RF Magnetron Sputtering for Medical Applications International-presentation

    T. Narushima

    Thermec’2006, International Conference on Processing & Manufacturing of Advanced Materials 2006/07/04

  87. Calcium Phosphate Coating on Titanium by RF Magnetron Sputtering for Medical Applications International-presentation

    T. Narushima

    Non-ferrous Metal Seminar between China and Japan 2006/03/15

  88. Calcium Phosphate Films Coated on Titanium by RF Magnetron Sputtering International-presentation

    T. Narushima

    Korea-Japan Symposium on Nano-Bio Technology –Interdisciplinary Science of Nanomaterials for Asia Core Program- 2006/02/14

  89. リン酸カルシウムコーティングによるチタン材料の生体機能化

    成島尚之

    学術討論会 若手生体材料研究者が目指す金属とセラミックス、高分子とのインテグレート生体機能材料 2006/01/16

  90. Characterization of Calcium Phosphate Films Prepared by RF Magnetron Sputtering International-presentation

    T. Narushima

    The 1st Korean-Japan joint workshop on biomedical materials 2005/12/12

  91. Characterization of Calcium Phosphate Films Prepared by RF Magnetron Sputtering International-presentation

    T. Narushima

    2005 MRS Fall Meeting 2005/11/28

  92. 東北大学先進医工学研究機構における生体材料に関する研究

    成島尚之

    東北大学 素材・材料開発研究会 2005/06/10

  93. Evaluation of Fatigue Property of Titanium Wires by Rotating-bending Testing in 1mass% Lactic Acid Solution International-presentation

    T. Narushima, K.Ueda, M.Yamashita, T.Murakami, C.Ouchi, Y.Iguchi

    The 9th Annual Conference of the International Functional Electrical Stimulation Society 2004/09/05

  94. Bio-materials Researches at Tohoku University International-presentation

    T. Narushima, T.Katsube, C.Ouchi, Y.Iguchi

    Symposium on Materials Science in Japan, China, and Korea 2004/06/15

  95. 新しい生体用チタン合金の研究開発動向とその課題

    成島尚之

    第17回歯科チタン学会 2004/02/14

  96. Nitridation of Titanium-Tin Alloys during Heating in Air International-presentation

    T. Narushima, K.Suzuki, S.Kimura, Y.Iguchi, C.Ouchi

    The 10th World Conference on Titanium 2003/07/13

  97. Refinement of β Grain Size Due to TiB or Y<SUB>2</SUB>O<SUB>3</SUB> Precipitates in Titanium Alloy International-presentation

    T. Narushima, K.Suzuki, S.Kimura, Y.Iguchi, C.Ouchi

    The 10th World Conference on Titanium 2003/07/13

  98. Calorimetric Study on Hydration of CaO-based Oxides International-presentation

    T. Narushima, Y.Iguchi, C.Izumi

    Kleppa Symposium, 2000 Annual Spring Meeting, TMS 2000/03

  99. Oxygen Distribution between Molten B<SUB>2</SUB>O<SUB>3</SUB> Flux and Indium or Gallium International-presentation

    T. Narushima, Y.Iguchi, M.Kinoshita, Y.Hino

    The 5th International Conference on Molten Slags, Fluxes and Salts 1997/01

  100. Determination of Free Lime Contents in Slags by Solution Calorimetry International-presentation

    T. Narushima, Y.Muraki, Y.Iguchi

    ICS'96 1996/04

  101. In situ Observation of Oxide Films Formed during Thermal Oxidation of SiC-B<SUB>4</SUB>C Composite International-presentation

    T. Narushima, M.Maruyama, H.Arashi, T.Goto, T.Hirai, Y.Iguchi

    European Ceramic Society 4th Conference 1995/09

  102. High-Temperature Active Oxidation of CVD-Si<SUB>3</SUB>N<SUB>4</SUB> in N<SUB>2</SUB>-O<SUB>2</SUB> Atmosphere International-presentation

    T. Narushima

    Advanced Materials '93 1993/10

  103. High-Temperature Active Oxidation of CVD-Si<SUB>3</SUB>N<SUB>4</SUB> in Ar-O<SUB>2</SUB> Atmosphere International-presentation

    T. Narushima, Y.Iguchi, T.Goto, T.Hirai, Y.Yokoyama

    SSI-8 1991/10

  104. High-Temperature Oxidation of CVD-SiC in CO-CO<SUB>2</SUB> Atmosphere International-presentation

    T. Narushima, T.Goto, Y.Iguchi, T.Hirai

    High Temperature Corrosion of Advanced Materials and Protective Coatings 1990/11

  105. Active to Passive Transition in the Oxidation of CVD-SiC International-presentation

    T. Narushima, T.Goto, T.Hirai

    MRS International Meeting on Advanced Materials 1988/06

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Industrial Property Rights 13

  1. NiTi系合金材料、NiTi系合金の製造方法、NiTi系合金材料からなる線材または管材、およびその製造方法

    山下史祥、喜瀬純男、藤井美里、石川浩司、成島尚之、上田恭介、加藤卓

    Property Type: Patent

    Holder: 国立大学法人東北大学、株式会社古河テクノマテリアル

  2. チタン素材の脱酸方法

    松若大介, 成島尚之, 上田恭介

    Property Type: Patent

    Holder: 株式会社神戸製鋼所

  3. METHOD FOR PURIFYING TITANIUM MATERIAL

    MATSUWAKA Daisuke, NARUSHIMA Takayuki, UEDA Kyosuke

    Property Type: Patent

    Holder: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.)

  4. 光触媒機能性部材およびその製造方法

    成島尚之, 上田恭介, 上田隆統志, 佐渡翔太, 小笠原康悦, 伊藤甲雄, 金高弘恭

    Property Type: Patent

    Holder: 国立大学法人東北大学

  5. 耐熱Ti合金および耐熱Ti合金材

    成島尚之, 上田恭介, 前田幸大, 鈴木聡

    Property Type: Patent

    Holder: 国立大学法人東北大学

  6. Ti-Si系合金の脱酸方法

    松若大介, 成島尚之, 上田恭介, 渡辺将仁

    Property Type: Patent

  7. NiTi系超弾性合金材料または形状記憶合金材料及びこれを用いた線材または管材

    成島尚之, 上田恭介, 原健治, 山下史祥, 石川浩司

    Property Type: Patent

  8. チタン合金とアルミニウム材料の接合方法

    村上太一, 大内千秋, 成島尚之, 井口泰孝

    Property Type: Patent

  9. 自動骨延長用装置及びその使用方法

    成島尚之, 勝部朝之, 川村仁

    Property Type: Patent

  10. 酸化物の還元反応を利用した発泡金属製造法

    村上太一, 成島尚之, 井口泰孝, 大内千秋

    Property Type: Patent

  11. 産業副生成物からのマグネシウム及びカルシウム除去回収とA型ゼオライト製造方法

    村上太一, 成島尚之, 井口泰孝, 大内千秋, 菅野善之

    Property Type: Patent

  12. ゼオライトの製造方法

    成島尚之, 井口泰孝, 大内千秋, 木浪常利, 菅野善之

    Property Type: Patent

  13. Ca-βアルミナとジルコニア固体電解質よりなる結合型ガスセンサー

    鹿野弘, 会田広治, 井口泰孝, 成島尚之, 中澤壮三

    Property Type: Patent

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Research Projects 32

  1. Materials surface design to inactivate coronaviruses by focusing on spike proteins

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: Tohoku University

    2021/04/05 - 2025/03/31

  2. 表面化学反応機構の理論的解明による耐熱材料の高精度制御

    佐原 亮二, 成島 尚之, 上田 恭介

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 基盤研究(B)

    Institution: 国立研究開発法人物質・材料研究機構

    2021/04/01 - 2024/03/31

  3. Functionalization of implant by bio-active coating with ion release and high bonding strength

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2020/04/01 - 2024/03/31

  4. Creation of optically-functional titanium surface with compatibility of bone forming ability and antibacterial activity and its application to implants

    Narushima Takayuki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2018/04/01 - 2022/03/31

    More details Close

    We succeeded in fabricating a Ti surface with both osteogenic and antibacterial properties for application to dental implants. The Au-containing TiO2 layers prepared on the Ti surface by an original process based on Au-sputtering and thermal oxidation showed antibacterial activity against E. coli under visible-light irradiation. The photofunction of the Au-containing TiO2 layers obtained in this study is considered to be an achievement to realize the “self-maintenance function” in which the implant itself plays a role in “healing” by reattaching to bone tissue and also enables “prevention” by patients themselves. These results, together with the excellent adhesion between the TiO2 layers and the Ti substrates, are expected to be applied not only to dental implants but also to the prevention of contact infection of the new coronavirus (SARS-CoV-2).

  5. Removal of oxygen from titanium melt using hydrogen plasma arc: Challenge to 300 ppm

    Narushima Takayuki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Challenging Research (Exploratory)

    Institution: Tohoku University

    2018/06/29 - 2020/03/31

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    The oxygen removal process from titanium melt, which was considered difficult in the past, has been established. The process consists of hydrogen plasma arc melting (first-step melting) and argon plasma arc melting (second-step melting). Oxygen removal from 0.127 mass% (1270 mass ppm) to 0.034 mass% (340 mass ppm) was achieved in the titanium melt by optimizing in melting conditions such as hydrogen partial pressure, melting time, gas flow rate and plasma current. Thermodynamic consideration suggested that the dissolved hydrogen introduced into titanium melt in response to the high hydrogen potential of active atomic hydrogen in plasma functions as a deoxidizer in the second-step melting. An international patent application was filed based on the results of this research.

  6. Release Release of bone morphogenetic protein using amorphous calcium phosphate film as a carrier

    UEDA KYOSUKE

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (C)

    Institution: Tohoku University

    2017/04/01 - 2020/03/31

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    The surface treatment process for both improving the bone compatibility and achieving antibacterial property on Ti implants was established by focusing on the dissolution of amorphous calcium phosphate (ACP). Bone morphogenetic protein (BMP) was loaded on the surface of the ACP coating films fabricated by RF magnetron sputtering. Sustained release of BMP through the dissolution of ACP coating film was observed. Ag- and Ta- co-added ACP coating film was fabricated by controlling the composition of the target during the sputtering process. The dissolution of Ag-added ACP coating films in simulated body fluids was suppressed by the addition of Ta in the coating film. It was estimated that the long-term antibacterial activity and improving the bone formation of the Ti implants by the release of Ag ion and ACP coating films, respectively.

  7. Fabrication of drug-release type implant using amorphous calcium phosphate film as a carrier

    Ueda Kyosuke, KANETAKA Hiroyasu

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Challenging Exploratory Research

    Institution: Tohoku University

    2015/04/01 - 2017/03/31

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    Bone morphogenetic protein (BMP) was loaded on amorphous calcium phosphate (ACP) film by immersion in BMP-2 solution. The releasing behavior of BMP-2 from ACP film was evaluated. The amount of BMP-2 loaded on ACP film by immersion in PBS(-) without heparin was higher than that with heparin. The BMP-2 loaded on ACP film by immersion in PBS(-) without heparin was released continuously for 12 h.

  8. Construction of a new implant recovery system by low-temperature plasma jet irradiation

    Kanetaka Hiroyasu, SASAKI Keiichi, NARUSHIMA Takayuki, KANEKO Toshiro, KAWASHITA Masakazu, KUDO Tada-aki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2013/04/01 - 2016/03/31

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    The aim of this study was to construct dental implant recovery system in the oral cavity due to a completely new approach based on three pillars; ① powerful sterilization and infected tissue removal, ② re-activation treatment of the implant surface, ③ tissue regeneration, as a method of obtaining a functional and morphological recovery in the oral cavity without removing the dental implant with peri-implant inflammation. As research results, by application of the latest technology of low-temperature plasma jet, the base of the dental implant recovery system to promote good tissue regeneration was constructed by carrying out the safe sterilization and surface re-activation treatment in the oral cavity for the implant which has lost its biological activity.

  9. Biofunctionalization of metallic biomaterials by forming ceramic interface layers

    NARUSHIMA Takayuki, KASUGA Toshihiro, OGASAWARA Kouetsu, UEDA Kyosuke

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: Tohoku University

    2013/04/01 - 2016/03/31

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    Ceramic coating layers of amorphous calcium phosphate (ACP) and TiO2 were prepared on Ti, and their antibacterial activities were evaluated. Ag-containing ACP layers fabricated by RF magnetron sputtering exhibited antibacterial activity through the continuous release of Ag ions, caused by the resorbability of ACP. TiO2 layers fabricated by thermal oxidation processes showed photodegradation of organic compounds and antibacterial activity under both UV- and visible-light irradiation. The introduction of Au into TiO2 layers from Ti-Au alloy substrates contributed to the expression of visible-light response. The optimized fabrication processes provided the coating films with both the bone forming ability and antibacterial activity.

  10. Formation of porous surface on NiTi and suppression of Ni ion release

    UEDA Kyosuke, NARUSHIMA Takayuki, KATO Hidemi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Challenging Exploratory Research

    Institution: Tohoku University

    2012/04/01 - 2014/03/31

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    A dealloying Ni surface having a porous structure was prepared from NiTi alloys through immersion in molten metals. The concentration of Ni from the NiTi substrate to the surface was decreased in a stepwise manner forming an inner Ti2Ni layer and outer alpha-Ti layer on the substrate. The amounts of metallic ions eluted from these specimens to 1mass% lactic acid solution were evaluated. Despite the increased surface area of the dealloyed specimen, Ni ion elution was suppressed to the same level as that in the non-treated NiTi substrate. The anatase layer formed by two-step thermal oxidation suppressed the Ni ion release from the dealloyed substrate.

  11. Osteogenesis by gradually expanding the interface between bone surface and periosteum

    KAWAMURA HIROSHI, NARUSHIMA Takayuki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2011/04/01 - 2014/03/31

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    We are investigating to regenerate bone by osteogenesis using gradually expanding the interface between bone surface and periosteum. In this study we developed the new dental implant system to obtain quick and broad adherence to surrounding bone to use for the regenerated bone. We evaluated thin amorphous calcium phosphate films coated on the surface of titanium dental implants using magnetron sputtering. The coated thin amorphous phosphate films induced early not only distance osteogenesis from the bone surrounding implants but also inner osteogenesis in the surface layers of the films. The implants showed early good mechanical fixation.These results suggested that implants coated with thin amorphous phosphate layers improve implant fixation and accelerate bone response.

  12. Development of bone-compatible interface using bioresorbable calcium phosphate coating film

    NARUSHIMA Takayuki, UEDA Kyosuke, KAWAMURA Hiroshi, KASUGA Toshihiro, TAIRA Masayuki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2010 - 2012

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    In vivo and in vitro evaluations of an amorphous calcium phosphate film formed on commercially pure titanium were conducted. Titanium implants coated with amorphous calcium phosphate were given to the femur and tibia of white rabbits. The implant stability quotient (ISQ) and bone implant contact for titanium implants were statistically improved by the coating of amorphous calcium phosphate. The coating film was absorbed during an implantation period of two-weeks; the release of Ca and P-related ions due to this absorption was suggested to play an important role in the improvement of bone compatibility. Further, the addition of Nb to the amorphous calcium phosphate film was an effective technique to control its resorbability in biological environments.

  13. Surface modification of titanium by pack cementation process for improvement of bone compatibility

    UEDA Kyosuke, NARUSHIMA Takayuki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Young Scientists (B)

    Institution: Tohoku University

    2009 - 2010

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    Calcium phosphate reaction layers were fabricated on titanium by pack cementation process, isobaric-isothermal process and their combination process to improve the bonecompatibility of titanium. The phase of the reaction layer was hydroxyapatite (HAp) and Ca-P-O-Ti graded layer, and its thickness was several μm. The reaction layer showed high bonding strength to the substrate and high ALP activity by the cell culture test. These results suggested that the new process effectively improved the bone compatibility of titanium.

  14. Ceramic surface modification of titanium for controlling bone-forming ability

    NARUSHIMA Takayuki, UEDA Kyosuke

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2007 - 2009

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    The formation and evaluation of bio-ceramic layer for improving bone-forming ability of titanium have been investigated, and the following results were obtained. (1) The bioresorbable amorphous calcium phosphate coating fabricated using RF magnetron sputtering improved the bone-compatibility of titanium implants. (2) The anatase-rich film with high bone-forming ability was fabricated on titanium by the newly developed two-step thermal oxidation process with low-cost and simplicity.

  15. 生体吸収性材料とチタン合金を用いた自家骨再生・修復デバイス開発-治験申請を目指す

    成島 尚之, 勝部 朝之, 川村 仁, 後藤 孝, 井口 泰孝, 大内 千秋

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 萌芽研究

    Institution: 東北大学

    2005 - 2006

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    本年は、生体吸収性を有するリン酸カルシウムコーティング膜として、擬似体液中における迅速なアパタイト形成及びカルシウムイオン溶出が確認された非晶質リン酸カルシウム(ACP)に着目し、その生体内外評価を行うと共に、β型チタン合金の人工歯根としての可能性を検討した。 (1)ACP膜の生体外評価: ACPコーティング膜のチタン基板との密着力をアルミニウムスタッド引き抜き法により評価した。コーティングままでは、60MPa以上の密蒲力が得られたが、擬似体液中へ浸漬後の密着力は30MPaへと低下した。これに対し、ブラスト処理を施したチタン基板においては、擬似体液浸漬後においてもコーティングままと同等以上の密着力が得られた。インプラント用コーティング膜の密着力としては50MPa以上が必要とされているが、それを満足するものと評価できる。 (2)ACP膜の生体内評価: 前年にビーグル犬下顎骨に埋入したACPコーティングを施したチタンシリンダーと骨界面の骨接触率を評価した。その結果、8-12週埋入後において、ACPコーティング膜の存在が骨接触率を有意(P<0.05)に上昇させることを見出した。また、インプラント-骨界面における新生骨量に関しても、ACPコーティング材において有意(P<0.05)に大きいことがわかった。 (3)コーティング膜総合的評価: 生体内外評価によりRFマグネトロンスパッタリング法により作製した生体吸収性ACPコーティング膜はチタンの骨適合性を向上させることが明らかとなった。 (4)β型チタン合金の人工茜根への応用: Ti-6at%Mo-4at%Snを素材とした人工歯根のビーグル犬下顎骨への埋入実験を行い、骨接触率に関してCPチタン材と大きな差異のないことを確認した。

  16. Surface hardening process accompanying with grain refinement in titanium materials using methane gas

    NARUSHIMA Takayuki, MURAKAMI Taichi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: TOHOKU UNIVERSITY

    2005 - 2006

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    (1) Methane gas treatment Maximum surface hardness and hardening layer depth were 850Hv and 230gm, respectively, for Ti-6A1-4V alloy after the treatment in Ar-5%CH_4 mixture gas at 1198 K for 10.8 ks. As for Ti-4.5A1-3V-2Fe-2Mo (SP-700) alloy, the maximum surface hardness of 880 Hv and the hardening layer depth of 130gm were obtained after the treatment in Ar-5%CH_4 mixture gas at 1073 K for 21.6 ks. It was suggested that the use of methane gas is effective for hardening in titanium materials. However, the amounts of dissolved hydrogen into the titanium alloys were not sufficient for grain refinement. (2) Treatment in methane-hydrogen mixture gas Both alloys were treated in the atmosphere of CH_4:H_2=1:1 at 1023 K for 1.8 ks, followed by aging and dehydration treatments. However, no grain refinement was obtained for both the alloy after these treatments, though the hydrogen content of 1 mass% was achieved. (3) Treatment in hydrogen gas In order to understand the interaction between titanium and hydrogen, the microstructure change of the titanium alloys was investigated under the conditions of hydrogen dissolution at 1023 K for 1.8 ks, aging at 523-873 for 28.8 ks and dehydration at 973-1173 for 3.6 ks. The grain refinement was achieved in Ti-6A1-4V alloy with aging at 773 K and dehydration at 973 to 1173 K. On the other hand, acicular alpha phase was observed instead of fine alpha grain for SP-700 alloy. The beta transus of SP-700 is 100 K lower than that of Ti-6A1-4V. Therefore, the strain introduced during hydrogen dissolution and aging processes in SP-700 alloy was not enough for recrystallization or recovery. The further study upon the hydrogen dissolution conditions is required.

  17. Development of titanium wire ropes for implantable stimulation electrode and their evaluation.

    NARUSHIMA Takayuki, OUCHI Chiaki, IGUCHI Yasutaka, TAIRA Masayuki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: TOHOKU UNIVERSITY

    2004 - 2005

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    Wear property and related issues such as wear debris formation, ion elution, surface hardening using gas, reaction between cell and titanium powder were investigated using biomaterials for medical applications. (1) Wear properties of implant materials in simulated body fluids 1. Ion elution into 1 mass% lactic acid solution during pin-on-disk wear test of titanium materials was more significant than that into Hanks' solution. 2. Wear loss calculated from mass loss was almost constant with sliding distance or contact pressure for biomaterials examined, while elution rate of metal ions increased with increasing sliding distance. 3. When CP titanium pin and disk were used for wear test, the wear loss was higher than that of α+β titanium alloys. It was suggested that adhesive wear occurred at the interface between CP Ti pin and disk. 4. When PSZ or Si_3N_4 pin and CP Ti disk were used, wear loss was lower than that using other ceramic pin, and elution rate was higher. (2) Effect of the surface hardening on wear property of titanium 1. Mass loss during pin-on-disk wear test for CP titanium or β-type Ti-14Mo-3Nb-1.5Zr alloy was decreased by surface hardening using CO gas. 2. The surface hardening using CO gas for CP titanium was more effective than that for β-type Ti-14Mo-3Nb-1.5Zr alloy, because solubility of oxygen or carbon in CP titanium with α type structure was much higher than in β-type titanium alloys. (3) In vivo and in vitro evaluation of wear debris 1. Titanium powder caused the ion elution in simulated body fluids, but the ion elution is relatively low in total ion elution during wear test. 2. RAW 264 cell viability was decreased by titanium ion, and the titanium ion affected the SOD activity and TNF-α formation. 3. It was observed that RAw264 cells phagocytosed titanium powder with 10 μm in diameter, which suggested the active interaction between the cell and titanium powder.

  18. Development of titanium wire ropes for implantable stimulation electrode and their evaluation

    IGUCHI Yasutaka, OUCHI Chiaki, NARUSHIMA Takayuki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: TOHOKU UNIVERSITY

    2004 - 2005

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    1. Development of titanium wore for implantable stimulation electrodes (1) α+β type Ti-4.5Al-6Nb-2Fe-2M titanium alloy was drawn to the wire with 100 μm in diameter. Anodic oxidation was effective to the oxide formation on the surface for wire drawing. In the atmospheric oxidation for oxide formation process, it was suggested that the low temperature process was preferred. (2) β type Ti-14Mo-3Nb-1.5Zr titanium alloy was drawn to the wire with 42 μm in diameter. The low temperature atmospheric oxidation was used for oxide formation process on the surface. In addition to that, the β type alloy was drawn to 100 μm in diameter using anodic oxidation, which showed the smooth surface after drawing. (3) CP titanium (4N) was drawn to the wire with 47 μm in diameter. The surface morphology of this wire was better than that of commercially available CP titanium wire with 46 μm in diameter. (4) α type Ti-10Zr titanium alloy was drawn to the wire with 51 μm in diameter, which exhibited the excellent surface smoothness and mechanical properties. The wire ropes with 7 and 7x7 strands made of Ti-10Zr titanium alloy were successfully developed. 2. Evaluation (1) The maximum tensile strength and total elongation of CP titanium wire with 47 μm in diameter were 980 MPa and 3.5 %. The mechanical properties of the β type Ti-14Mo-3Nb-1.5Zr titanium alloy wire and the α type Ti-10Zr titanium alloy wire were measured. (2) The fatigue limits of the developed CP titanium wire with 47 μm in diameter and commercially available CP titanium wire with 46 μm in diameter were 200 MPa and 300 MPa, respectively. The difference of fatigue limit may be caused by the surface roughness after fatigue testing. The commercially available CP titanium wire exhibited the smoother surface than developed CP titanium wire after 10^7 cycles.

  19. 低温プラズマ・水素還元法による高純度チタン粉末製造プロセスの研究

    井口 泰孝, 成島 尚之, 大内 千秋

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 萌芽研究

    Institution: 東北大学

    2003 - 2003

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    これまでSiF_4を原料とした太陽電池用シリコン粉末製造に使用されていた同軸マグネトロン型プラズマ処理法を応用して、クロール法と同じ原料の液体TiCl_4からのチタン製造プロセスの検討を行い、以下の結果を得た。 1.原料としてはTiCl_4の液体を用いるので、同軸マグネトロン型プラズマ処理装置のガス導入系を改良して液体原料を保持する容器を据え付けると共に、その蒸気をチャンバー内に搬送することができるようにした。 2.TiCl_4気化温度100〜150℃、水素流量80sccm、チャンバー圧力4Torr、RF入射電力1.5〜2kW、反射電力0.1KWとした合成条件下における2時間の反応により約20〜30%の収率で、主にTiCl_3粉末が得られた。TiCl_3は大気中の水蒸気の反応によりTicl_3・6H_2Oとして存在していた。また、一部TiO_xの存在もX線回折により確認された。 3.TiO_xの存在は、チタン金属粉末が大気中の酸素または水蒸気と反応して形成されたものと予想される。従って、原理的には、低温プラズマを利用した本方法によりTiCl_4(1)から金属チタンの製造は可能と思われる。Ticl_4の還元を十分進行させ、金属チタンの収率を向上させるためには、(i)水素ガスの供給量(分圧)を向上させる、(ii)チャンバー中の反応領域の体積を増加させるなどの対応が有効と考えられる。

  20. Anisotropy of silicon carbide crystal : Approaches in terms of surface process and high-temperature oxidation

    NARUSHIMA Takayuki, IGUCHI Yasutaka, OUCHI Chiaki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (C)

    Institution: Tohoku University

    2002 - 2003

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    The anisotropy of physical and chemical properties of silicon carbide (SiC) crystal was investigated with the approaches in terms of surface process and high-temperature oxidation. 1.Oxidation of SiC Oxidation kinetics of CVD-SiC and single crystalline SiC in ozone-containing atmospheres at temperatures from 573 to 1273K up to 345.6ks were evaluated by the measurement of oxide thickness on the specimen. The oxidation rate of (0001^^_) C face in the ozone-containing atmospheres was much higher than that of (0001) Si face as well as in oxygen atmosphere previously reported. The measurement of the oxidation rates of single crystalline SiC revealed that the order of the oxidation rates was (0001^^_)> (12^^_10) >(101^^_0)> (0001). This order well corresponds to the density of carbon on the individual face. The oxidation rate on (0001) Si face in the ozone-containing atmospheres relatively increased compared with that in other oxidation atmospheres such as dry oxygen or wet oxygen. This result suggests that the use of ozone gas as oxidant in semiconductor device fabrication process might be effective for rapid oxidation at low temperatures. 2.Surface process in SiC Negative crystal was introduced into the SiC single crystal. The shape change of the negative crystal was measured at 2473 K. The faceting of the negative crystal suggested that {0001} was stable face, a part of the Wulff shape, while {121^^_0} was unstable face, not a part of Wulff shape. The rate of shape change of the negative crystals obtained in the experiments was compared with that calculated using the model, in which the driving force of shape change assumed to be the difference of chemical potential on the surface. The rate controlling process of shape change was the surface attachment limited kinetics (SALK) for on-axis face, while the. contribution of surface diffusion on the rate controlling process was suggested for off-axis face.

  21. Development of the adsorbent for heat storage system using iron and steel making slag as source material

    OUCHI Chiaki, SAHARA Ryoji, NARUSHIMA Takayuki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (C)

    Institution: TOHOKU UNIVERSITY

    2002 - 2003

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    The heat storage system using water vapor adsorption to zeolite materials is getting much attention because of extremely high energy density and flexibility of process. The composition of zeolite A can be shown as M_XAl_XSi_<1-X>・nH_O. The hydrophiic property of zeolite A is excellent because of high Al/Si ration in the zeolite A. The blast furnace slag mainly consists of SiO_2, Al_2O_3, CaO and MgO. Since Ca and Mg can be introduced to zeolite A as M, the blast furnace slag is a promising candidate for source materials of zeolite A. In the present work, the alkali hydrothermal process for production of zeolite A from the blast furnace slag as a source material was investigated. The following results were obtained; 1.Zeolite A can be synthesized from SiO_2-Al_2O_3-CaO slag by hydrothermal treatment in the conditions; Temperature: 328-393 NaOH: 0.5-3 M NaOH solution : slag (source material): 15 (mug) 2.The zeolite A synthesized by the hydrothermal process was thermally stable up to 873 K. 3.In order to obtain zeolite A from blast furnace slag in the hydrothermal process, the adjustment of composition was needed. It was required to decrease the content of CaO+MgO in the blast furnace slag. The less the content of CaO+MgO, The more the ratio of zeolite A to total products after hydrothermal synthesis. 4.The rate of the hydrothermal reaction increased by using the ball-mill-type chamber. 5.It was confirmed that the zeolite A obtained in the present work was applicable to the heat storage system because endothermic reaction was observed during the heating of the zeolite A.

  22. Abrasion and ion elution of implantable metallic electrode in bending-rotating fatigue testing

    IGUCHI Yasutaka, NARUSHIMA Takayuki, OUCHI Chiaki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: TOHOKU UNIVERSITY

    2002 - 2003

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    The fatigue properties of stainless steel wire ropes and titanium wires in simulated body fluids at 310 K were investigated in rotating-bending testing as a fundamental study for applications to the FES (Functional Electrical Stimulation) electrode. 1.Stainless steel wire rope (1)The new stainless steel (Fe-22Cr-10Ni-6Mn-2Mo-0.4N) wire rope exhibited the higher fatigue strength and wear corrosion resistance than the type SUS3 16L stainless steel wire rope under low maximum bending stress level. (2)The metal ion concentrations in the lactic acid solution increased with increasing of number of cycles in fatigue testing, which agreed with the chemical composition of the stainless steels. On the other hand, in Hanks' solution, they are suppressed at the low level, and the order of the amounts of ion elution was Ni>Cr>Fe. (3)The ferric oxyhydroxides (β-FeOOH) was formed in Hanks' solution as corrosion products during fatigue testing, which might keep iron and chromium ions at low concentration in Hanks' solution. 2.Titanium wires (1)The wire made of the new β-type titanium alloy, Ti-14Mo-3Nb-1.5Zr, had excellent fatigue strength compared with the C.P.Ti wire. (2)The ratio of fatigue limit (σ_f) to tensile strength (σ_U) of the C.P.Ti wire was less than 30 percent, which might be caused by the surface flaws introduced during the cold working process. (3)The C.P.Ti wire with diamond like carbon (DLC) coating exhibited the relatively high value of σ_f/ σ_U. This result suggests that the fatigue life of the titanium wire can be improved by the optimization of the DLC coating process.

  23. Oxidation mechanism of silicon and silicon-based ceramics in ozone-containing atmosphere.

    NARUSHIMA Takayuki, IGUCHI Yasutaka

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (C)

    Institution: TOHOKU UNIVERSITY

    1999 - 2000

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    Introduction The oxidation kinetics of silicon and silicon carbide were investigated in an oxygen-ozone atmosphere at 973 K, and the possible oxidation mechanism of silicon-based materials is discussed. Experimental The samples used for oxidation tests were single crystalline silicon, polycrystalline silicon carbide (CVD), and single crystalline α(6H)-silicon carbide. An oxygen-ozone mixture gas (ozone gas partial pressure : 2-7 kPa, total pressure : 0.1 MPa) was generated with a silent discharge ozonizer system using dry oxygen as a source gas. Oxidation temperature was 973 K.Thickness of the oxide film formed on a sample was measured by ellipsometry at a fixed refractive index (1.462). The oxide films were examined by secondary ion mass spectroscopy (SIMS). Results and discussion (1) Oxidation kinetics Parabolic behavior was observed at 973 K in oxygen-ozone mixture gas for the oxidation of silicon carbide C-face, Si-face and silicon. The oxidation rates of silicon and silicon carbide were much higher than those in pure oxygen. Atomic oxygen supplied by the dissociation of ozone gas seems to cause the increasing of oxidation rates, and the atomic oxygen diffusion through silica film is a rate-controlling process for oxidation because parabolic rate constant increased linearly with ozone gas partial pressure. (2) High oxidation rate of SiC C-face The oxidation rates of silicon carbide C-face in ozone-containing atmospheres are higher than those of Si-face and silicon. The higher oxidation rates of C-face than those of silicon may be caused by carbon in silica film formed on C-face detected with SIMS.

  24. Development and Evaluation of Alloys for the Electrodes for Functional Electrical Stimulation to Appropriate for the Long Term Implantation

    IGUCHI Yasutaka, IIKUBO Tomohito, HANDA Yasunobu, HOSHIMIYA Nozomu

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B).

    Institution: Tohoku University

    1998 - 2000

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    Alloys for the electrodes for FES(Functional Electrical Stimulation)were developped and evaluated to appropriate for thelLong term implantation. And following results were obtained. 1. Development of New Alloy : A database for alloy designing was created. And ingots of some high-manganese high-nitrogen austenitic stainless steels were producted experimentaly. Relation between reduction and elongation or reduction of area of these alloys were tested. And, it was confirmed that the alloy named NAS106N(6mass%Mn, 10mass%Ni, 22mass%Cr, 2mass%Mo, 0.4mass%N)shows the most superior properties. And thin wire rope for FES electrodes were made by this alloy. 2. Evaluation of FES Electrodes made by New Alloy : Magunetization curves of FES wires made by newly developed alloy NAS106N, stainless steell SUS316L and cobalt-chromium based alloy NAS604PH were measured. NAS106N and NAS604PH shows the superior non-magnetic properties than SUS316L, Fatigue life of electrodes made by NAS106N, NAS605PH, SUS316L in air and 0.9%NaCl saline solution were also measured by dual-driven rotating-bending test. NAS106N has higher fatigue life than SUS316L and NAS604PH at all experimental condition in air and high at stress conditions in saline solution. On the other hand, fatigue lives of SUS316L and NAS106 were lower than NAS604PH at low stress condition in saline solution. Accordingly, NAS106N will be promising material for FES electrodes but to prevent the fretting corrosion should be the problem to be solved.

  25. オゾンガスによるシリコンおよびシリコン基セラミックスの酸化機構解明

    成島 尚之

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 基盤研究(C)

    Institution: 東北大学

    1998 - 1998

  26. In-situ Observation of Oxide Films Formed During Thermal Oxidation of Liquid Al Alloy Using Raman Spectroscopy

    NARUSHIMA Takayuki, IGUCHI Yasutaka

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (C)

    Institution: TOHOKU YNIVERSITY

    1996 - 1997

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    The formation of oxide films on liquid Al and al alloys was observed during oxidation process at 1273 K in an oxygen atmosphere by Raman spectroscopy, and the mass change due to the oxidation was measured. The following results were obtained ; 1.The oxidation process of liquid Al alloys was consisted of three stages, initial, incubation and accelerating. However, the accelerating stage was not observed for pure Al, Al-4mass% Mg, Al-4mass%Mg-1mass%Si and Al-4mass%Mg-4mass%Si. 2.MgO and spinel (MgO・Al_20_3) were formed in the initial stage of oxidation by the reaction between Mg vapor and oxygen gas. The oxidation reaction is sustained in the incubation stage by the wicking of a liquid metal through the spinel layr formed in the initial stage. Completing of the wicking may lead the accelerating stage, in which alpha-Al_20_3 was mainly formed and remarkable mass gains were observed. 3.In situ Raman spectra of oxide filmed were obtained during oxidation process of Al-1mass%Mg (with accelerating stage) and Al-4mass%Mg (without accelerating stage). The Raman peaks of spinel (MgO・Al_20_3) and alpha-Al_20_3 appeared for Al-1mass%Mg during holding at 1273 K.Both of the Raman peaks periodically disappear during the holding, which was caused by the presence of the liquid metal on the surface of the oxide film. The liquid metal flowed over the surface through cracks of the oxide films. The formation of cracks was confirmed by in situ observation of oxidation process using optical microscopy. On the other hand, the formation of spinel was observed for Al-4mass%Mg during holding at 1273 K,and the other Raman peaks were not detected for 5 hours, which means that the wicking of liauid metal through the spinel phase has not completed yat.

  27. Development of Implantable Electrode for Functional Electrical Stimulation.

    IGUCHI Yasutaka, NARUSHIMA Takayuki, HANDA Yasunobu, HOSHIMIYA Nozomu

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: TOHOKU UNIVERSITY

    1994 - 1996

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    The functional electrical stimulation (FES) system is very effective in order to restore motor functions of the paralyzed extremities in spinal cord injury and carebral disease patients. The applicants have been developed as stimulator with percutaneous intramuscular electrodes and have been utilizing clinically the system. However, this system has unavoidable problems such as infection and breakage at the position where electrodes go through skin, careful daily maintenance, and cosmetically unfavorable upon patients. Therefore, development of a totally implanted FES system is necessary. In this study more reliable electrodes have been developed than the present percutaneous electrodes. The obtained results are as follows : 1. Chromium-cobalt alloy was refined by electro-slag remelting and 25 mum diameter wire was drawn as well as SUS316L stainless steel. The mechanical properties were well satisfied. 2. Pitting corrosion was observed on the SUS316L wire in saline solution with accelerated corrosion test by applying electric current, on the contrary, no pitting corrosion on the 604PH wire. 3. In order to easily and stably connect electrodes with the stimulator during operation, design of connectors and electrode tip were developed. 4. Prototype systems of totally implanted FES with the electrodes of two kinds of materials (SUS316L and 604PH) were implanted in sheep and operating check of the system has been carried out. Useful information has been expected for development of the final system.

  28. Hydrogen Analysis by Using of Secondary Ion Mass Spectroscopy

    NARUSHIMA Takayuki, IGUCHI Yasutaka

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for General Scientific Research (C)

    Institution: TOHOKU UNIVERSITY

    1994 - 1995

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    (1) Hydrogen analysis Hydrogen analysis by using of secondary ion mass spectroscopy (SIMS) was carried out for the standard sample (SiO_2 on silicon) in which proton was implanted, and the optimum analytical conditions for hydrogen analysis were clarified. It is important for hydrogen analysis to control the raster size of an ion beam, neutralization, signal gating and so on. (2) Wet oxidation rate Wet oxidation rates of chemically-vapor-deposited silicon carbide (CVD-SiC) and silicon nitride (CVD-Si_3N_4) were measured by a thermogravimetric technique. The oxidation films were analyzed by XRD and Raman spectroscopy. The oxidation rate was increased with increasing of water vapor pressure and decreasing of oxygen pressure in the atmosphere. This may be lead by the change of micro-defects in the oxide film (silica). Water vapor in the atmosphere accelerated the crystallization of oxide film at lower-temperatures (around 1373 K) and non-crystallization at higher-temperatures (>1873 K). It was clarified by laser Raman spectroscopy that amorphous silica was at around oxide/gas interface and cristobalite was at around oxide/ceramics interface, i.e., the oxide film formed was a duplex one. These results suggested that the formation of amorphous silica lowered the oxidation resistance of siliconbased ceramics for wet oxidation.

  29. Development of"in situ"measuring system for an oxidization process of metals by using Raman spectroscopy

    ARASHI Haruo, SHIMIZU Ryousuke, NARUSHIMA Takayuki, IGUCHI Yasutaka

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Developmental Scientific Research (B)

    Institution: TOHOKU UNIVERSITY

    1993 - 1994

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    Laser Raman spectroscopy is one of the most suitable methods for"in situ"observation of the oxidization process of metals from the following points of view ; specimens are not destroyed and a small area can be analyzed by micro-Raman spectroscopy. We developed the "in situ"measuring system, which has a triple monochromator, a CCD detector, and a heating stage which can change the environmental conditions, for an oxidization process of metals by using Raman spectroscopy. This system clarified that the growth process of oxide films during thermal oxidization of Fe-6.5mass%Si alloy at 1073K in O_2 and CO_2 atmospheres depends on the concentration of the oxygen defects in the SiO_2 surface layr. This system also performed to observe the oxidization of the liquid Al and Al-Mg alloys at 1273K. This system developed in this study is the suitable method for"in situ"observation of oxidization especially at high temperatures.

  30. Distribution of impurity elements between flux and melt during the growth of III-V compound semiconductor single crystals.

    YASUTAKA Iguchi, WATANABE Masatoshi, NARUSHIMA Takayuki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for General Scientific Research (B)

    Institution: TOHOKU UNIVERSITY

    1993 - 1994

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    1. Phase diagrams of III group oxide-B_2O_3 binary systems. No phase diagrams has been reported in Ga_2O_3-B_2O_3 and In_2O_3-B_2O_3 systems, and one phase diagram in Al_2O_3-B_2O_3 system. In the present work, solubility of III group oxide (Ga_2O_3, In_2O_3, Al_2O_3) in B_2O_3 melt and the solid phase equilibrated with the melt were determined. The phase diagrams of Ga_2O_3-B_2O_3, In_2 O_3-B_2O_3, and Al_2O_3-B_2O_3 binary systems were constructed with high accuracy using these data. 2. Oxygen solubility in liquid gallium and liquid indium. The oxygen solubility in liquid gallium or liquid indium equilibrated with solid Ga_2O_3 or In_2O_3, respectively was determined as follows : log (O/mass% in liquid gallium) =-6200/T+2.61 (T : 1123-1523 K) log (O/mass% in liquid indium) =-6600/T+3.77 (T : 1073-1373 K) Using the temperature dependence of the oxygen solubility, the standard free energy change for oxygen dissolution in liquid gallium or liquid indium could be represented as follows : 1/20O_2 (g) =O (mass% in liquid gallium) , DELTAG゚=-2.45x10^5+59.6T (J) 1/20O_2 (g) =O (mass% in liquid indium) , DELTAG゚=-1.79x10^5+33.8T (J) 3. Oxygen distribution between flux and melt Oxygen distribution between III group metal oxide (Ga_2O_3 or In_2O_3) -B_2O_3 binary flux and liquid III group metal (Ga or In) was investigated in the view point of fundamental study for LEC method. Distribution ratio of oxygen for the Ga system at 1423 K and the In system at 1373 to 1473 K were determined. The activity of Ga_2O_3 and In_2O_3 in B_2O_3 flux were found to be small, which suggested that oxygen content in III-V compound melts might be suppressed to be lower level in the LEC process.

  31. ラマン分光法によるシリカ酸化皮膜の結晶化のその場観察とその酸化速度に及ぼす影響

    成島 尚之

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 奨励研究(A)

    Institution: 東北大学

    1991 - 1991

  32. シリコン基セラミックスの超高温低酸素分圧下における酸化機構

    成島 尚之

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 奨励研究(A)

    Institution: 東北大学

    1989 - 1989

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