Hafnium carbonitride (HfC_xN_1–x) ceramics have drawn considerable interest due to their exceptional mechanical and thermophysical properties. Herein, we report a novel single-source precursor with Hf–N bonds as the main chain and fabricate HfC_xN_1–x ceramics after pyrolysis of the precursor. The synthesis, ceramic conversion, and microstructural evolution of the single-source precursor as well as the derived HfC_xN_1–x ceramics treated under various atmospheres were investigated. The results indicate that in an argon atmosphere, the nitrogen content within HfC_xN_1–x decreases with rising temperature. While under a nitrogen atmosphere, the high concentration of N₂ facilitates the rapid conversion of HfO₂ to Hf₇O₈N₄, which subsequently promotes the transformation of the HfC_xN_1–x solid solution ceramics. During this process, there is also an inhibitory effect of N₂ on the tendency of HfN into HfC. Moreover, the desired chemical composition of HfC_xN_1–x can be regulated by adjusting the N₂ concentration in the heat treatment atmosphere. The present work proposes a novel strategy for the single-source precursor-derived carbonitride ceramics and provides a deep understanding of the preparation and property modulation of HfC_xN_1–x ceramics.

中文翻译：

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从分子前驱体到超高温陶瓷：碳氮化铪纳米陶瓷的新型合成


碳氮化铪 （HfC_xN_1–x） 陶瓷因其卓越的机械和热物理性能而引起了相当大的兴趣。在此，我们报道了一种以 Hf-N 键为主链的新型单源前驱体，并在前驱体热解后制备了 HfC_xN_1-x 陶瓷。研究了在各种气氛下处理的单源前驱体以及衍生的 HfC_xN_1-x 陶瓷的合成、陶瓷转化和微观结构演变。结果表明，在氩气气氛中，HfC_xN_1-x 内的氮含量随着温度的升高而降低。在氮气气氛下，高浓度的 N₂ 促进了 HfO₂ 向 Hf₇O₈N₄ 的快速转化，从而促进了 HfC_xN_1-x 固溶体陶瓷的转化。在此过程中，N₂ 对 HfN 转化为 HfC 的趋势也有抑制作用。此外，可以通过调整热处理气氛中的 N₂ 浓度来调节所需的 HfC_xN_1-x 的化学组成。这项工作为单源前驱体衍生的碳氮化物陶瓷提出了一种新的策略，并提供了对 HfC_xN_1-x 陶瓷的制备和性能调制的深刻理解。