Effect of ZrC–SiC content on microstructure and ablation properties of C/C composites

C/C–ZrC–SiC composites with different ZrC–SiC contents were fabricated by precursor infiltration and pyrolysis. The effect of ceramic content on the microstructure and ablation resistance was investigated. Both the C/C–SiC and C/C–ZrC–SiC composites exhibited good ablation resistance under the plasma flame above 2300 °C. With the increase of ZrC content, a continuous oxide layer and a solid Zr–Si–O mesophase were formed during the ablation. And the structure of the formed oxides layer closely linked with the contents of ZrC–SiC ceramics. The solid ZrO 2 –ZrC and Zr–Si–O mesophase could increase the viscosity of SiO 2 moderately and improve the anti-scouring ability. The continuous SiO 2 –ZrO 2 –ZrC–SiC layer would serve as a thermal and oxygen barrier for preventing the substrate from further ablation. The C/C–ZrC–SiC composites with 27.2% ZrC and 7.56% SiC shows superior ablation resistance, and the mass and linear ablation rates are −3.51 mg/s and −1.88 μm/s, respectively.