Ultra-high temperature ablation property of Ta0.5Hf0.5C ternary ceramic under plasma flame

Abstract

The Ta0.5Hf0.5C ternary ceramic is desirable due to its ability to withstand ultra-high temperature ablative conditions because of its high oxidation resistance among TaxHf1-xC systems. This work reports the ultra-high temperature ablation of a polycrystalline and fully dense Ta0.5Hf0.5C ternary ceramic under a plasma flame that achieved 2200 °C on the sample surface and was maintained for 30 s. The mass loss rate and linear recession rate of the Ta0.5Hf0.5C ternary ceramic during plasma flame test were 0.67 ± 0.02 mg/s and 2.38 ± 0.05 μm/s, respectively. The coexistence of Ta2O5 and the high-melting Hf6Ta2O17 framework on the surface of the composite contributed to the increase of ablative property when comparing with the typical ZrB2-15 vol.% SiC ceramic reference system. Ablation behavior, microstructure evolution, and ablation mechanisms of Ta0.5Hf0.5C ceramics are discussed and compared to the baseline sample.