PREPARATION AND ANTI-OXIDATION BEHAVIOR OF MULLITE COATING ON CARBON/SILICON CARBIDE COMPOSITE

Ethyl orthosilicate(TEOS)and aluminum nitrate were used as raw materials for preparation of mullite sol.The mullite coating(MC)on carbon/silicon carbide(Cf/SiC,f refers to fiber,the same below)was prepared by the dip coating method.Isothermal oxidation tests were performed on Cf/SiC and Cf/SiC MC and their oxidation behaviors were studied.The results show that the oxida-tion of Cf/SiC and Cf/SiC MC can be divided into three main stages:θ700℃,700℃θ1 000℃,1000℃θ1 200℃.The oxidation rate-determining steps for each stage are different;the mass loss percentage of the Cf/SiC MC was fifty percent lower than that of the Cf/SiC.The Cf/SiC MC has good oxidation resistance.