Ablation behaviour of C/C and C/C–ZrC–SiC composites with cone-shaped holes under an oxyacetylene flame

• The ablation resistance of C/C–ZrC–SiC is superior in HF1 but is contrary in HF2.
• ZrO2–SiO2 double-structure results in good ablation resistance of C/C–ZrC–SiC in HF1.
• Collapse of ZrO2 contributes to poor ablation resistance of C/C–ZrC–SiC in HF2.

The ablation behaviour of C/C and C/C–ZrC–SiC composites with cone-shaped holes was studied under an oxyacetylene flame in two heat fluxes. The results showed that C/C–ZrC–SiC composites had a superior ablation resistance in the heat flux of 2.38 MW/m2, mainly owing to the ZrO2–SiO2 with double structure formed on the surface. As ablated in the heat flux of 4.18 MW/m2, the ablation resistance of C/C–ZrC–SiC composites was worse than that of C/C composites since the high temperature corrosion resulted in a heavy evaporation of SiO2 and the left ZrO2 skeleton was easily scoured away by the strong scouring force of flame.