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

Abstract

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 ZrO2–ZrC and Zr–Si–O mesophase could increase the viscosity of SiO2 moderately and improve the anti-scouring ability. The continuous SiO2–ZrO2–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.