Ablative and Mechanical Properties of C/C–ZrC Composites Prepared by Precursor Infiltration and Pyrolysis Process

C/C–ZrC composites with continuous ZrC matrix were prepared by precursor infiltration and pyrolysis process using zirconium-containing polymer. Ablation properties of the composites were investigated by oxyacetylene flame with heat flux of 2380 and 4180 kW/m2, respectively. The results showed that C/C–ZrC composites exhibited excellent ablation resistance under the heat flux of 2380 kW/m2 for 120 s and a tree-coral-like ZrO2 protective layer formed after ablation. However, when the heat flux increased to 4180 kW/m2, the maximum temperature of ablated surface reached 2500 °C and a strong degradation of ablation resistance was observed due to the weak bonding between the formed ZrO2 layer and the composites. The flexural strength of C/C–ZrC composites was 110.7 ± 7.5 MPa. There were a large number of carbon fiber bundles pull-out, and the composites exhibited a pseudo-plastic fracture behavior.