Exceptional Oxidation Resistance of High‐Entropy Carbides up to 3600 °C

Abstract

Abstract Achieving exceptional oxidation resistance at elevated temperatures is long desirable for ultrahigh‐temperature materials to be used in relevant applications such as hypersonic flights, re‐entry vehicles, and propulsion systems. However, their practical service temperatures are typically limited to below 3000 °C. Here, the exploration of (Hf, Ta, Zr, W)C high‐entropy carbides with exceptional oxidation resistance of 2.7 µm·s −1 up to 3600 °C through a high‐entropy compositional engineering strategy is reported. This impressive oxidation behavior arises from the formation of unique dual‐structural oxide layers involving numerous high‐melting‐point W particles uniformly embedded within molten (Hf, Me) 6 (Ta, Me) 2 O 17 (Me = metal element, Hf, Ta, Zr, and W) primary oxides. The developed (Hf, Ta, Zr, W)C demonstrates a significant breakthrough for ultrahigh‐temperature applications up to 3600 °C, paving the way for further design of advanced ultrahigh‐temperature materials capable of serving at higher service temperatures.