Formation mechanism of (Ti, Zr, Hf)C medium-entropy carbide derived from polymer precursors and its modification on the ablative mechanism of C/C-SiC composites

Medium-entropy carbide (MEC) of (Ti, Zr, Hf)C was synthesized and its modification on the ablative mechanism of C/C-SiC composites was investigated. After 60 s oxyacetylene flame test, the mass and linear ablation rates were 1.43 mg/s and 11.1 μm/s, respectively. The evolution of ceramics oxide scale dominated the anti-ablation process, which transfers from (Ti, Zr, Hf)xCyOz, (Ti, Zr, Hf)xSiyOz to (Ti, Zr, Hf)O2, (Zr, Hf)TiO4. With further evaporation of SiO2, the generated (Ti, Zr, Hf)O2 skeleton and the residual liquid oxides ((Zr, Hf)TiO4 and (Zr, Hf)SiO4) can block the oxygen channel and further reduce oxidation of the inner matrix.