The oxidation behavior and mechanical properties of MoSi2–CrSi2–SiC–Si coated carbon/carbon composites in high-temperature oxidizing atmosphere

A MoSi2–CrSi2–SiC–Si multi-component coating was prepared on the surface of carbon/carbon (C/C) composites by a two-step pack cementation method. The microstructure, oxidation behavior and mechanical properties of the coating were studied. These results show that the multi-component coating could protect the C/C composites from oxidation in air at 1873 K for 300 h and withstand 30 thermal cycles between 1873 K and room temperature, respectively. The mass loss and mechanical property loss of the coated C/C composites are considered due to the worse fluidity of SiO2 at intermediate temperatures and the thermal mismatch between the coating and C/C composites.

► The coating can protect the C/C composites from oxidation at 1873 K for 300 h. ► The coating can withstand 30 thermal cycles between 1873 K and room temperature. ► The worse fluidity of SiO2 and thermal mismatch can cause mass loss of the specimens. ► Rapid cooling and thermal mismatch will cause some mass loss of the specimens. ► Rapid cooling and thermal mismatch can cause the mechanical properties decrease.