Oxidation behaviour and mechansim of MoSi₂-CrSi₂-SiC-Si coating for carbon/carbon composites from room temperature to 1873 K

A MoSi₂-CrSi₂-SiC-Si coating was prepared on the surface of carbon/carbon (C/C) composites by a two-step pack cementation method. The microstructure and oxidation behaviour of the coating were studied. These results illustrated that the coating could effectively protect C/C composites from oxidation from oxidation in air above 1600 K, due to the protection of the compound glass. The weight loss of the coated C/C specimens was only 0.4% after oxidation at 1873 K for more than 150 h. The coating lacked effective oxidation resistance for C/C composites from 800 to 1600 K, as no obvious glass layer covered the coating surface and the cracks cannot be sealed because of the high viscosity of the compound glass.