1995 Fiscal Year Final Research Report Summary
Role of Sintering Additives in Si-Ti-C Composites
| Project/Area Number |
06453082
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Composite materials/Physical properties
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
ISEKI Takayoshi Tokyo Institute of Technology/Facul.of Eng., Prof., 工学部, 教授 (10016818)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAZAKI Hiroyuki Tokyo Institute of Technology/Facul.of.Eng., Res.Assoc., 工学部, 助手 (30239389)
YANO Toyohiko Tokyo Institute of Technology/R.L.N.R., Assoc.Prof., 原子炉工学研究所, 助教授 (80158039)
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| Project Period (FY) |
1995
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| Keywords | Silicon carbide / Titan carbide / Composite / SiC-TiC / Ti_3SiC_2 / Spark plasma sintering / Strength |
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| Research Abstract |
To improve the fracture toughness of SiC,TiC particle dispersed SiC matrix composites have been studied. SiC-Tic composite doped with 2wt% Ti could be hot-pressed to nearly theoretical density at 2000ﾟC, and its bending strength did not degrade until 1200ﾟC.However, the bending strength of the SiC-TiC composite doped with Ti decreased severely at 1400ﾟC.The purpose of this study is to clarify the reason of degradation of the strength at 1400ﾟC,and to find a fabrication method of a composite which has high strength even at high temperature.
It was observed that free Si and Ti_3SiC_2 existed in the composites containing lower carbon content, besides SiC and TiC as principal phases. The intensity of X-ray diffraction peaks of Si and Ti_3SiC_2 and the density of specimens decreased with the increment of carbon content. Whereas monolithic SiC doped with Ti could not be densified. Therefore, it is believed that the existence of Si and Ti_3SiC_2 contributes to the densification of the SiC-TiC composites doped with Ti.
The existence of free Si in the composite and weak interface layr between SiC and TiC and a chemical reaction at 1400ﾟC could be a reason of poor strength at 1400ﾟC.Oxidation resistance of the SiC-TiC composite was better than TiC.
Finally, it is suggested that a SiC-TiC composite fabricated by spark plasma sintering method or by hot-pressing method with addition of boron using stoichiometric TiC could be expected to possess superior high temperature bending strength.
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