LPCVD-based SiO2/SiC multi-layers coating on graphite for improved anti-oxidation at wide-ranged temperatures

A novel SiO2/SiC multilayer coating was prepared on graphite by low-pressure chemical vapor deposition (LPCVD) with the aim of enhancing oxidation resistance at wide-ranged elevated temperatures. The anti-oxidation tests were performed at 1000 °C and 1500 °C in ambient air. The results showed that oxidation of SiO2/SiC multilayer coating was a continuous weight gain process, compared to the fast weight-loss of single SiC coated specimens. The final weight gains of SiO2/SiC coated specimens after oxidation at 1000 °C and 1500 °C for 120 h in ambient air are 0.116 mg/cm2 and 0.225 mg/cm2, respectively. The superior anti-oxidation performance of SiO2/SiC multilayer coating is ascribed to the intact combination between layers and excellent self-healing ability of SiO2 at elevated temperature.