Ablation behavior of C/SiC-HfC composites in the plasma wind tunnel

In order to satisfy the requirements for the thermal protection system to serve at ultrahigh temperatures, carbon fiber reinforced silicon carbide-hafnium carbide (C/SiC-HfC) composites were fabricated by reactive melt infiltration method. The ablation behaviors of C/SiC-HfC composites were examined in plasma wind tunnel. The results indicated that ablation was controlled by the oxidation of HfC-SiC under dissociated oxygen conditions at low heat flux and stagnation pressure. However, a sudden temperature jump caused by the change in the catalytic surface from silica to hafnia was observed at high heat flux and stagnation pressure during ablation. The increase in surface temperature was further accelerated by the burning of carbon fiber and recombination of carbon and nitrogen on it.