Cyclic ablation behavior of C/C-ZrC-SiC composites under oxyacetylene torch

Cyclic ablation behavior of C/C-ZrC-SiC composites prepared by precursor infiltration and pyrolysis process was studied using oxyacetylene torch. After repeated 30 s ablation for four times, the composites exhibited better ablation properties than those under single ablation for 120 s because of the lower surface temperature, and their linear and mass ablation rates were -3×10^-4 mm/s and -2.29×10^-3 g/s, respectively. A continuous ZrO₂-SiO₂ layer formed on the surface of center ablation region and acted as an effective barrier to the transfer of heat and oxidative gases into the inner material. Thermal stress induced by repeated impact of oxyacetylene led to some cracks on the ZrO₂-SiO ₂ layer; however its destructive power was weaker than that of higher temperature. Stick like silica as grown silica nanowires were generated in the transition ablation region due to the evaporation of silicon oxide at appropriate temperature.