Oxyacetylene ablation of (Hf0.2Ti0.2Zr0.2Ta0.2Nb0.2)C at 1350-2050 °C

Ablation resistance of a multi-component carbide (Hf0.2Ti0.2Zr0.2Ta0.2Nb0.2)C (HTZTNC) was investigated using an oxyacetylene flame apparatus. When the surface temperature of the HTZTNC was below 1800 degrees C, (Nb, Ta)2O5, (Hf, Zr)TiO4, and (Hf, Zr)O2 were found to be the main oxidation products, while at higher temperature, for-mation of (Hf, Zr, Ti, Ta, Nb)Ox was favored and its content gradually increased with the increase in ablation temperature. Based on the ablation results and thermodynamic simulation analysis, a possible ablation mech-anism of HTZTNC was proposed. Active oxidation of TiC and outward diffusion of TiO were demonstrated to occur during the ablation process, which constitute the critical steps for the ablation of HTZTNC. These results can contribute to the design of ablation resistant ultra-high-temperature ceramics.