A novel MoSi2-rich coating on the SiC-Si coated C/C composites for the preparation and antioxidative properties at 1773 K and 1973 K

To provide a long-term oxidative protection for C/C composites at elevated temperatures, we designed and fabricated a novel MoSi2-rich oxidation protective coating on the surface of SiC-Si coated C/C composites by a combined method of powder reactive sintering and molten silicon infiltration. The phase composition, microstructure and oxidation protective performance of the coating were investigated. The results show that as-prepared MoSi2-rich coating had a dense structure with multiphase mosaic. After oxidation for 581 h at 1773 K in air, the mass loss of the coated specimen was only 1.83%. Particularly, the composite coating can effectively prevent C/C substrate from oxidation for more than 200 h at 1973 K in air, indicating that it possessed outstanding antioxidative capacity due to the rapid formation of the dense SiO2 glass layer in a long-term high-temperature atmosphere. •Preparing a dense MoSi2-rich oxidation protective coating prepared on the SiC-Si coated C/C composites using a novel three-step method.•The MoSi2-rich/SiC-Si coating can effectively prevent the C/C composites from isothermal oxidation at 1773 K for more than 500 h and at 1973 K for more than 200 h in air, respectively.•The main protective mechanism is attributed to the high density of the MoSi2-rich coating and the continuous formation of a compact and self-healing SiO2 glass layer.