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<p>High-entropy carbides (HECs) with superior oxidation resistance above 3000 °C are in great demand for ultrahigh-temperature applications. However, related studies are rare. Here, we report the development of a non-equimolar (Hf<sub>0.2</sub>Zr<sub>0.2</sub>Ta<sub>0.3</sub>W<sub>0.3</sub>)C HEC with exceptional oxidation resistance up to 3700 °C, through systematically tailoring the proportion of oxidation products in the (Hf, Zr, Ta, W)C series. Specifically, we first confirm the crucial role of the (Hf, Zr)<sub>6</sub>Ta<sub>2</sub>O<sub>17</sub>/W dual structure: high-melting-point W serves as a skeleton to stabilize molten (Hf, Zr)<sub>6</sub>Ta<sub>2</sub>O<sub>17</sub>, while the latter acts as an effective barrier to impede the inward oxygen diffusion and encapsulate W to hinder its oxidation. We next optimize the volume ratio between (Hf, Zr)<sub>6</sub>Ta<sub>2</sub>O<sub>17</sub> and W, finding that a ratio of 5.5:4.5 is optimal for the oxidation resistance of HECs. The subsequent study shows that the optimized oxidation productions with enhanced thermal stability, can further positively contribute to the oxidation resistance of HECs, resulting in a nearly 100% improvement in non-equimolar (Hf<sub>0.2</sub>Zr<sub>0.2</sub>Ta<sub>0.3</sub>W<sub>0.3</sub>)C compared to previously reported equimolar (Hf<sub>0.25</sub>Zr<sub>0.25</sub>Ta<sub>0.25</sub>W<sub>0.25</sub>)C. The exceptional oxidation resistance is also verified by oxidation testing with extended duration and thermal cycling testing. This work reports a novel material capable of serving under ultrahigh-temperature oxidizing environments.</p>

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Composition engineering of high-entropy carbides for superior oxidation resistance up to 3700 °C

  • 期刊论文

  • 发表日期：

    2026年3月26日

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  • Zihao Wen,
  • Yaming Fu,
  • Lei Zhuang,
  • Hulei Yu,
  • Yanhui Chu

摘要

High-entropy carbides (HECs) with superior oxidation resistance above 3000 °C are in great demand for ultrahigh-temperature applications. However, related studies are rare. Here, we report the development of a non-equimolar (Hf0.2Zr0.2Ta0.3W0.3)C HEC with exceptional oxidation resistance up to 3700 °C, through systematically tailoring the proportion of oxidation products in the (Hf, Zr, Ta, W)C series. Specifically, we first confirm the crucial role of the (Hf, Zr)6Ta2O17/W dual structure: high-melting-point W serves as a skeleton to stabilize molten (Hf, Zr)6Ta2O17, while the latter acts as an effective barrier to impede the inward oxygen diffusion and encapsulate W to hinder its oxidation. We next optimize the volume ratio between (Hf, Zr)6Ta2O17 and W, finding that a ratio of 5.5:4.5 is optimal for the oxidation resistance of HECs. The subsequent study shows that the optimized oxidation productions with enhanced thermal stability, can further positively contribute to the oxidation resistance of HECs, resulting in a nearly 100% improvement in non-equimolar (Hf0.2Zr0.2Ta0.3W0.3)C compared to previously reported equimolar (Hf0.25Zr0.25Ta0.25W0.25)C. The exceptional oxidation resistance is also verified by oxidation testing with extended duration and thermal cycling testing. This work reports a novel material capable of serving under ultrahigh-temperature oxidizing environments.