| Project/Area Number |
11450255
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Composite materials/Physical properties
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| Research Institution | OSAKA PREFECTURE UNIVERSITY |
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Principal Investigator |
OKAMURA Kiyohito GRADUATE SCHOOL OF ENGINEERING, OSAKA PREFECTURE UNIVERSITY, PROFESSOR, 工学研究科, 教授 (70005974)
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| Co-Investigator(Kenkyū-buntansha) |
KATASE YOSHlRO GRADUATE SCHOOL OF ENGINEERING,OSAKA PREFECTURE UNIVERSITY, RESEARCH ASSOCIATES, 工学研究科, 助手 (00081373)
NARISAWA MASAKI GRADUATE SCHOOL OF ENGINEERING,OSAKA PREFECTURE UNIVERSITY, ASSISTANT PROFESSOR, 工学研究科, 講師 (00244658)
SHIMOO TOSHIO GRADUATE SCHOOL OF ENGINEERING, OSAKA PREFECTURE UNIVERSITY, ASSOCIATE PROFESSOR, 工学研究科, 助教授 (10081374)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥11,400,000 (Direct Cost: ¥11,400,000)
Fiscal Year 2001: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2000: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1999: ¥8,200,000 (Direct Cost: ¥8,200,000)
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| Keywords | High-Temperature Creep / Ceramic Matrix Composites / Silicon Carbide Fibers / High-Temperature Oxidation / Active Oxidation Behavior / Precursor Polymers / 高温クリープ装置 / 活性酸化 / セラミック繊維 / 高温クリープ線性 |
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| Research Abstract |
Three types of SiC fibers for reinforced fibers of ceramic-matrix composites (CMC) are commercially available ; Nicalon (SiC_<1.34>O_<0.36>), Hi-Nicalon (SiC_<1.39>0_<0.01>) and Hi-Nicalon-Type S (SiC_<1.05>). The first fiber contains an amorphous silicon oxycarbide (SiC_XO_Y) phase, next one is low-oxygen contained fiber and is microcrystalline, and finally, nearly stoichiometric sintered SiC fiber. Such differences in oxygen content and microstructure may greatly affect the properties of the fibers at high temperatures in different environments. Under high and moderate oxygen partial pressures, the SiC fibers are passively oxidized and the resulting stable silica film protects the material from further oxidation. Under low oxygen partial pressures, the SiC fibers are subjected to active-oxidation accompanied by the formation of gaseous products, resulting in serious damage to the SiC fibers. In the present work, these SiC fibers were oxidized at 1773K in Ar-O_2 gas mixtures with oxyg
… More
en partial pressures (po_2) from 1 to 10^5 Pa to investigate the active-to-passive oxidation transition. The active-oxidation occurred at po^2≦100 Pa for Nicalon, po^2≦10 Pa for Hi-Nicalon and po^2≦1 Pa for Hi-Nicalon-Type S. The po^2 values are dependent upon the amounts of SiC_XO_Y phase. On the other hand, it is important to investigate creep behavior of these fibers in order to obtain a better understanding of the reliability for reinforcement of high temperature CMC. Tensile creep tests were performed on single filaments in air and Ar gas at 1573-1723 K with an applied load of 0.35-0.75 Gpa. The creep apparatus was originally produced with the support by Grant-in-Aid for Scientific Research ((B)(2)). From the values of the stress exponents and the activation energies for creep in air and Ar gas, the creep deformation mechanisms of Nicalon, Hi-Nicalon and Hi-Nicalon-Type S are associated with the grain-boundary diffusion, grain-boundary sliding and the movement of dislocations, respectively. The differences between the creep parameters of these fibers in air and Ar were not almost observed. Thus, at the present time Hi-Nicalon-Type S will be best for the majority of CMC applications. Less
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