電子線不融化法によって合成された低酸素SiC系繊維の酸化機構

概要

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The mechanism of oxidation of a low oxygen SiC fiber prepared by the electron radiation curing method was investigated. The oxidation rates were measured with a thermobalance in O_2 at temperatures from 1373 to 1773 K. The reaction products were examined by X ray diffraction and SEM observation. The oxide finn was amorphous silica below 1573 K and crystallized to cristobalite above 1673 K. The core crystallized to form a trace of β SiC, accompanying the formation of amorphous free carbon. The oxide film suppressed the pyrolysis of the core. The oxidation rate obeyed the diffusion controlled contracting disc formula. The acti vation energy was 234 kJ/mol. The oxidation is consi dered to be controlled by the gas diffusion through the micropores in the silica film. The reduction of oxygen content in the polymer derived SiC fibers is effective not only for suppression of the high temperature pyrol ysis but also for improvement of the oxidation resistance.
社団法人日本セラミックス協会の論文
1994-07-01