Microstructure and ablation behavior of C/C–HfC composites prepared by precursor infiltration and pyrolysis

• C/C-HfC composites were prepared by precursor infiltration and pyrolysis (PIP).
• C/C–HfC composites exhibit good ablation resistance for 240 s.
• During ablation, the formation of HfO2 and HfCxOy protected the composites.

C/C–HfC composites were prepared by precursor infiltration and pyrolysis using HfC precursor. The microstructure, mechanical properties, and ablation behavior were investigated. The C/C–HfC composites showed good ablation resistance with a surface temperature over 2573 K during ablation. The ablation process was divided into two steps, with the ablation rate dominated by various mechanisms. During ablation, tree-coral-like HfO2 particles formed and functioned as thermal barrier, and the HfCxOy phase acted as oxygen diffusion barrier, protecting the composites from further ablation.