Ablation mechanism of Cf/(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C-SiC composite during plasma ablation above 2000 °C

Air plasma ablation behavior of Cf/(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C-SiC composite was studied systematically with the surface temperature above 2000 °C at the ablation center. It presents a linear recession rate of 0.15 μm/s and a mass recession rate of 2.05 mg/s after ablation at 4 MW/m2 (2000°C) for 300 s. Associated with the temperature gradient of the ablation surface, the oxidation products at different locations mainly consist of (TiZrHfNbTa)Ox, (ZrxHf1–x)6(NbyTa1–y)2O17, Ti(NbxTa1–x)2O7, (HfxZr1–x)SiO4, and SiO2. Due to the synergistic effect of the multi-component oxides, oxidation products form a protective structure composed of high melting point oxide skeleton filled with relatively low melting point phases. It retards oxygen inward diffusion and prevents the composite fragmentation caused by plasma mechanical scouring. It is believed that the results would be helpful for further improving the ablation resistance by component design of high entropy ceramics and their composites.