Oxidation Resistance Mechanism of Wide-Temperature Anti-Oxidation Coatings for C/C Composites

The oxidation resistance of C/C composites in dynamic environments across a wide temperature range still needs improvement. Studies have shown that doping with Al can enhance the oxidation resistance of ultra-high-temperature ceramic coatings over a broad temperature range. However, there has been limited research on the oxidation behavior of Al-doped ultra-high-temperature ceramic coatings under dynamic conditions.In this study, HMSSB (HfB 2 , MoSi 2 , SiC, SiO 2 , B 2 O 3 ) coatings and Al-doped HMSSB (A-HMSSB) coatings were prepared on SiC-coated C/C composites. After oxidation at 1200°C and 1500°C for 4 h and 5 h, respectively, the SiC/HMSSB composite coating exhibited significant porosity, leading to severe oxidation of the C/C substrate. In contrast, the SiC/A-HMSSB coating formed a dense and well-sealed oxide glass layer, resulting in lower mass loss rates of 10.08% and 9.23% after oxidation.