Oxidation protection of C/SiC coated carbon/carbon composites with Si–Mo coating at high temperature

To protect carbon/carbon (C/C) composites against oxidation, a Si–Mo coating was prepared on C/SiC-coated C/C composites by a simple slurry method. The microstructure of the coating was characterized by X-ray diffraction, scanning electron microscopy and Raman spectra. Results showed that the coating was mainly composed of SiC, MoSi2 and Si. It could protect C/C composites from oxidation at 1873 K in air for 300 h and withstand 13 thermal cycles between room temperature and 1873 K. The excellent oxidation and thermal shock resistance of the coating was attributed to the formation of dense SiO2 glass at high temperature. The volatilization of MoO3 and SiO2 at 1873 K was the main reason of the weight loss of the coated C/C composites.

Research highlights
► A Si-Mo coating was prepared on C/SiC-coated C/C composites by a simple slurry method.
► The coating could protect C/C composites from oxidation at 1873 K for 300 h.
► The coating withstand 13 thermal cycles between room temperature and 1873 K.
► Good oxidation and thermal shock resistance was attributed to the formation of SiO2 glass.