Oxidation behavior of SiC-Al₂O₃-mullite multi-coating coated carbon/carbon composites at high temperature

Oxidation kinetics of silicon carbide-alumina - mullite multi-coating coated carbon/carbon composites at high temperature was investigated. The SiC coating was prepared by a pack cementation process with Si, C, SiC, and Al ₂O₃ powders in an argon atmosphere at 1600°C for 2h. It was shown that the weight loss of the coated C/C was only 1.3% and 2.3% after oxidation at 1600°C for 45h and 81h. It was found that in 10h oxidation in air, no obvious rule was found between weight loss and time. It was also found that the oxidation activation energy was 122.3 kJ/mol in the range 1300-1460°C and 82.6 kJ/mol in the range 1460-1600°C.