Silicon carbide coating to protect carbon/carbon composites against oxidation

In order to protect carbon/carbon (C/C) composites from oxidation, a silicon carbide coating has been produced by a two-step pack cementation technique. XRD analysis showed that the inner coating obtained from the first step was a β-SiC layer and the outer coating formed by the second step pack cementation was composed of α-SiC, Si and β-SiC. The as-received coating provided excellent oxidation resistance, proving able to protect C/C composites from oxidation for more than 310 h at 1773 K in air. The weight loss of the coated C/C composites was considered to arise from the debonding of some glass and the formation of bubble holes on the coating surface.