Due to poor mechanical properties and antioxidation properties, etc of single phase ultrahigh-temperature ceramics (UHTCs), the second phase such as SiC was usually introduced for improving those properties. Herein, a novel stratagem for synthesis of binary HfC–SiC ceramics has been presented. A Hf–O–Hf polymer as a HfO₂ precursor has been synthesized for preparing soluble HfC–SiC precursors with high solid content and low viscosity solutions without additional organic solvents. The structure of PHO was characterized by FTIR and ¹H-NMR, the crystalline behavior and morphologies of polymer-derived ceramics were identified by XRD, SEM-EDS, and TEM. It was shown that PHO firstly transformed into HfO₂, and then reacted with in situ carbon derived from DVB and PCS thus producing cubic HfC through carbothermal reduction. In addition, the obtained HfC–SiC nanopowders exhibited spherical morphology with a diameter less than 100 nm, while the Hf, Si, and C are homogeneously distributed.

中文翻译：

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聚合物前驱体衍生的HfC–SiC超高温陶瓷纳米复合材料

由于单相超高温陶瓷（UHTC）的机械性能和抗氧化性能等较差，通常引入SiC等第二相来改善这些性能。在此，提出了一种合成二元HfC-SiC陶瓷的新策略。已经合成了Hf-O-Hf聚合物作为HfO ₂前驱物，用于制备具有高固含量和低粘度溶液的可溶性HfC-SiC前驱物，而无需使用其他有机溶剂。通过FTIR和¹ H-NMR对PHO的结构进行了表征，并通过XRD，SEM-EDS和TEM鉴定了聚合物衍生陶瓷的晶体行为和形貌。结果表明，PHO首先转化为HfO _2。，然后与衍生自DVB和PCS的原碳反应，从而通过碳热还原反应生成立方HfC。此外，获得的HfC–SiC纳米粉体呈现出直径小于100 nm的球形形态，而Hf，Si和C均匀分布。