SiO_2皮膜で被覆されたSi-C-O系繊維の熱安定性に及ぼす酸化条件の影響

概要

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To improve the high-temperature stability, Si-C-O fibers(Nicalon)were oxidized at temperatures of 1073-1773 K under an oxygen partial pressures of 2.53 × 10^4-1.01 × 10^5 Pa and then were exposed to 1773 K in argon. X-ray diffraction, resistivity measurement and tensile test were conducted for both the oxidized and the exposed fibers. At an early stage of oxidation, the characteristics of oxidized fibers abruptly changed. This was because an incomplete SiO_2 coating caused pyrolysis of the fibers. High levels of tensile strength was retained in the as-oxidized state at elevated oxidation temperatures and under high oxygen partial pressure. The strength of the oxidized fiber could be controlled by the imperfections of the SiO_2 film. After exposure in argon, the highest strength was retained in the fiber oxidized at 1373 K under an oxygen partial pressure of 2.53 × 10^4 Pa, that is, in the fiber having SiO_2-film thickness of 0.2 μm.
社団法人日本セラミックス協会の論文
1999-03-01