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Taguchi, Tomitsugu; Nozawa, Takashi*; Igawa, Naoki; Kato, Yutai*; Jitsukawa, Shiro; Koyama, Akira*; Hinoki, Tatsuya*; Snead, L. L.*
Journal of Nuclear Materials, 329-333(Part1), p.572 - 576, 2004/08
Times Cited Count：46 Percentile：92.89(Materials Science, Multidisciplinary)The SiC/SiC composite with SiC/C multi-layer interphase coated on advanced SiC fibers was fabricated by the forced thermal-gradient chemical vapor infiltration (F-CVI) process for improvement in mechanical properties. The SEM and TEM observation verified that SiC/C multi-layer interphase was formed on SiC fibers. The both flexural and tensile strengths of SiC/SiC composite with SiC/C multi-layer interphase were approximately 10 % higher than that with single carbon interphase. The SEM observation on the fracture surface of the composite with SiC/C multi-layer reveals that cylindrical steps around the fiber were formed. The several crack deflections occurred within SiC/C multi-layer interphase. The SiC/C multi-layer applied in this study operated efficiently to improve the mechanical properties.
Yamada, Reiji; Igawa, Naoki; Taguchi, Tomitsugu; Jitsukawa, Shiro
Journal of Nuclear Materials, 307-311(Part2), p.1215 - 1220, 2002/12
Times Cited Count：24 Percentile：80.63(Materials Science, Multidisciplinary)SiC fiber-reinforced SiC composites (SiC/SiC) are considered an advanced structural material for blanket modules of a fusion reactor, which requires high thermal conductivity in order to keep thermal stresses in the material lower than the allowable design stress. The sintered SiC fiber recently developed has obtained high thermal conductivity, so it is highly expected that sintered SiC fiber-reinforced SiC/SiC composites would also show high thermal conductivity. In this study several types of 3D SiC/SiC composites were fabricated by either CVI or PIP method. The results of the thermal conductivity measurements show that the maximum thermal conductivity at room temperature was about 60 W/mK for CVI composites or 25W/mK for PIP ones. These values are considerably higher than those of non-sintered SiC fiber reinforced SiC/SiC composites, which indicates a possibility that the developed materials would be promising. The FEM thremal analysis shows the good agreement between the caluculated and experimental results.
Taguchi, Tomitsugu; Igawa, Naoki; Jitsukawa, Shiro; Nozawa, Takashi*; Kato, Yudai*; Koyama, Akira*; Snead, L. L.*; McLaughlin, J. C.*
Advanced SiC/SiC Ceramic Composites: Developments and Applications in Energy Systems; Ceramic Transactions Vol. 144, p.69 - 76, 2002/00
Process optimization for Forced-thermal gradient Chemical Vapor Infiltration (FCVI) fabrication of 75 mm diameter size SiC composites with advanced SiC fibers; Hi-Nicalon Type S and Tyranno SA, was carried out. The SiC/SiC composites fabricated by FCVI exhibited significant reduction in porosity (15.1%) and more uniform pore distribution by decreasing the MTS and H
gases flow rates in the latter part of the FCVI process. The tensile strength of the both composites using Hi-Nicalon Type S or Tyranno SA fibers was slightly increased with increased thickness of carbon interphase in the range of 75-300 nm. In order to perform the comparative testing required to directly compare the thermomechanical property changes following neutron irradiation, larger composites with uniform microstructural property are required. From the results of process optimization for fabrication of 75 mm diameter size FCVI SiC/SiC composites, the definitive purpose in this study is the fabrication of the 300 mm diameter size SiC/SiC composite with the uniform microstructural properties.
Idesaki, Akira; Sugimoto, Masaki; Tanaka, Shigeru; Morita, Yosuke; Narisawa, Masaki*; Okamura, Kiyohito*; Ito, Masayoshi*
High Temperature Ceramic Matrix Composites, p.35 - 40, 2001/00
Silicon carbide (SiC) fiber, which is one of the likeliest candidates as a reinforcement fiber of ceramic matrix composites (CMCs), is synthesized from polycarbosilane (PCS). The diameter of thus SiC fibers is 10-15 
m. In order to fabricate CMCs with 3-dimensional complex shapes, it is important to develop a SiC fiber with diameter of less than 10 m, flexibility, and high strength. In order to improve the spinnability of precursor polymer, we have blended polyvinylsilane (PVS), which is a liquid polymer at room temperature, to PCS as a spinning additive. According to relationship between temperature and melt viscosity of the polymer blend, it was found that the polymer can be melt-spun at about 490K, 110K lower than PCS (about 600K), and that the spinnability of the polymer is improved by blending PVS. Fine polymer fiber was obtained from the polymer blend, and finally, very fine SiC fiber with the average diameter of 6 m was synthesized from the PCS-PVS polymer blend.
Seguchi, Tadao
Radiation Physics and Chemistry, 57, p.367 - 371, 2000/00
Times Cited Count：29 Percentile：85.04(Chemistry, Physical)no abstracts in English
*; *; Okamura, Kiyohito*; Sugimoto, Masaki; Seguchi, Tadao
Fine Ceramic Fibers, p.207 - 229, 1999/00
no abstracts in English
Idesaki, Akira*; Narisawa, Masaki*; *; Sugimoto, Masaki; Morita, Yosuke; Seguchi, Tadao; Ito, Masayoshi*
Key Engineering Materials, 164-165, p.39 - 42, 1999/00
no abstracts in English
/SiC compositesY.J.Stockmann*; Futakawa, Masatoshi; *; Tanabe, Yuji*; Kogawa, Hiroyuki; Hino, Ryutaro; *
Ceramic Material Systems with Composite Structures, 99, p.357 - 369, 1998/00
no abstracts in English
Fujii, Kimio; Yamada, Reiji
Journal of Nuclear Materials, 258-263, p.1953 - 1959, 1998/00
Times Cited Count：8 Percentile：57.28(Materials Science, Multidisciplinary)no abstracts in English
*; *; Okamura, K.*; Sugimoto, Masaki; Seguchi, Tadao; Ito, Masayoshi*
Progress in Advanced Materials and Mechanics (Proc. of ICAM-96), 0, p.121 - 125, 1996/00
no abstracts in English
Seguchi, Tadao; Sugimoto, Masaki; Okamura, K.*
Progress in Advanced Materials and Mechanics (Proc. of ICAM-96), 0, p.221 - 225, 1996/00
no abstracts in English
*; Okamura, K.*; Seguchi, Tadao
High-Temperature Ceramic-Matrix Composites II (HT-CMC2), 0, p.65 - 74, 1995/00
no abstracts in English
Seguchi, Tadao
Interijento Zairyo, 5(3), p.45 - 52, 1995/00
no abstracts in English
Sugimoto, Masaki; *; Okamura, K.*; Seguchi, Tadao
Journal of the American Ceramic Society, 78(7), p.1849 - 1852, 1995/00
Times Cited Count：39 Percentile：84.73(Materials Science, Ceramics)no abstracts in English
Sugimoto, Masaki; *; Okamura, K.*; Seguchi, Tadao
Journal of the American Ceramic Society, 78(4), p.1013 - 1017, 1995/00
Times Cited Count：75 Percentile：93.88(Materials Science, Ceramics)no abstracts in English
Seguchi, Tadao; Sugimoto, Masaki*; Okamura, K.*
High Temperature Ceramic Matrix Composites; 6th European Conf. on Composite Materials: HT-CMC, p.51 - 57, 1993/00
no abstracts in English
Seguchi, Tadao; Okamura, K.*
Kobunshi Kako, 42(4), p.163 - 168, 1993/00
no abstracts in English
Seguchi, Tadao; Kasai, Noboru; Okamura, K.*
Proc. of the 4th Int. Symp. on Advanced Nuclear Energy Research (JAERI-CONF 1/JAERI-M 92-207), p.62 - 65, 1992/12
no abstracts in English
*; *; *; *; Kasai, Noboru; Seguchi, Tadao; Okamura, K.*
Ceramic Engineering and Science Proceedings,Part 1, p.209 - 217, 1992/00
no abstracts in English
Seguchi, Tadao; *
Genshiryoku Kogyo, 38(8), p.64 - 69, 1992/00
no abstracts in English
