Cyclic ablation behaviors of mullite-modified C/C–ZrC–SiC composites prepared by PIP

Four mullite-modified C/C–ZrC–SiC composites with different contents were prepared by precursor infiltration and pyrolysis (PIP). The phase compositions, microstructures, and cyclic ablation behaviors of the composites under 2.38 MW/m² oxyacetylene flame were investigated. Results show that both insufficient and excessive amounts of mullite limit the ablation resistance of the composites. The composite with mullite content of 8.27 wt% has better ablation resistance, and the mass loss rate and linear loss rate after the second ablative are −0.873 mg/s and 0.272 µm/s, respectively. Appropriate mullite improves the viscosity and thermo-oxidative barrier properties of the liquid phase and enhances the healing of ablative defects. Meanwhile, mullite inhibits the crystal transformation of ZrO₂.