Structure and oxidation behaviors of C/C-SiC coated with Al ₂O₃-CrAl_0.42Si_1.58-SiC-Al ₄SiC₄ oxidation protection system

A multicomposition resistant coating for SiC coated carbon/carbon (C/C) composites was produced by pack cementation technique in an argon atmosphere. This multicomposition coating was characterized by X-ray diffraction and scanning electron microscopy technique, and the oxidation behaviors of C/C with this multicomposition coating were also investigated in air using thermogravimetry. The results indicate that a dense coating with an average thickness of 200 μm can be got using pack cementation technique. The coating is composed of Al₂O₃, CrAl_0.42Si _1.58, SiC, and Al₄SiC₄. This multicomposition coating could effectively protect the composites from exposure to atmosphere at 1873K for 49 h with the weight loss of the coated C/C composites being only 1.84%.