Ablation behavior of ZrB₂–SiC ceramics modified by low-temperature synthesized Ta₄HfC₅

The introduction of transition metal carbides has been shown to improve the oxidation resistance of ZrB₂-SiC ceramics at moderate temperatures; however, their effectiveness under ultra-high temperature ablation conditions remains limited. In this work, nanoscale Ta₄HfC₅ powder was synthesized at a low temperature (1400 °C) via a three-dimensional gel network, which enables ZrB₂-SiC-Ta₄HfC₅ ceramic to achieve high densification below 2000 °C. Oxyacetylene ablation tests at surface temperatures above 2100 °C demonstrated that the incorporation of Ta₄HfC₅ significantly improved the ablation resistance, resulting in a dense and adherent oxide layer with a negative linear ablation rate. The improved ablation behavior was associated with the formation of multicomponent oxides during high-temperature oxidation, which contributed to the stabilization of the oxide scale. This study highlights the potential of Ta₄HfC₅ as an effective functional additive for ZrB₂–SiC-based ultra-high temperature ceramics.