OXIDATION BEHAVIOR OF CARBON/CARBON COMPOSITE TREATED BY USING CHEMICAL VAPOR REACTION

Needled carbon cloth reinforced carbon/carbon (C/C) composite materials were improved by using the combination process of chemical vapor infiltration of carbon and direct reaction of silicon vapor with carbon at high temperature named as chemical vapor reaction (CVR) method to form SiC. Oxidation behavior of the obtained composites with various densities and open porosity was studied by static oxidation tests. The results show that, after being oxidated at 1160℃±10℃ for 65mins, the mass loss of the composites with a density of 2.47g/cm³ is less than 2.6%, while that of the same-structured C/C composite with a density of 1.95g/cm³ is as high as 32%. Treatment by CVR method can significantly improve the oxidation resistance properties. However, when the density of the C/C/SiC composite is lower and open porosity is higher, the effect is similar with C/C composite due to no formation of a continual layer of dense SiO₂ on the specimen surface.