Carbon fiber reinforced carbon matrix composites have excellent thermo-mechanical properties, but they are degraded rapidly by oxidation at high temperatures in air. Silicon carbide is the best candidate for the oxidation resistive coating for the carbon composites at high temperature. Multilayer oxidation resistive coating film consisting of three or four layers including silicon carbide has been prepared by chemical vapor deposition method and polymer precurser method. Microstructure and chemical composition of coating films were examined by electron microscopy techniques. It was found that carbon composites with multilayer coating films were stable at high temperature with a weight loss under 1% at 1700 and 1900 oC in high and low oxygen partial pressure environment.

Keywords: Sillicon carbide, Carbon composite, Yttria, Multilayer coating, Weight loss.