A novel single-source-precursor for SiC-TaC-C nanocomposites was successfully synthesized by the chemical reaction between a polycarbosilane (allylhydridopolycarbosilane, AHPCS) and tantalum(V) chloride (TaCl₅), which was confirmed by Fourier transform infrared spectra (FTIR) measurement. After pyrolysis of the resultant single-source-precursors at 900 °C, amorphous ceramic powders were obtained. The 900 °C ceramics were annealed at different temperatures in the range of 1200–1600 °C to gain SiC-TaC-C nanocomposites. The phase evolution of ceramic nanocomposites was investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results indicate that the TaC starts to crystallize at lower temperature than the β-SiC. It is particularly worth pointing out that the unique core-shell structured TaC@C nanoparticles were in-situ formed and homogeneously distributed in the ceramic matrix after annealing at 1400 °C. Even at a high temperature of 1600 °C, the grain sizes of β-SiC and TaC are smaller than 30 nm, fulfilling the definition of nanocomposites. The present study related to SiC-TaC-C nanocomposites paves a new road for enriching ultra-high temperature ceramic family suitable for structural/functional applications in harsh environment.

中文翻译：

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含核壳结构TaC @ C纳米粒子的SiC-TaC-C陶瓷纳米复合材料的单源前驱体合成和相演化

通过聚碳硅烷（烯丙基氢聚碳硅烷，AHPCS）与氯化钽（V）（TaCl ₅）之间的化学反应成功合成了一种新型的SiC-TaC-C纳米复合材料单源前体。），通过傅立叶变换红外光谱（FTIR）测量得到证实。在900°C下热解所得的单源前体后，获得非晶陶瓷粉末。在1200–1600°C的不同温度下对900°C的陶瓷进行退火，以获得SiC-TaC-C纳米复合材料。通过X射线衍射（XRD）和透射电子显微镜（TEM）研究了陶瓷纳米复合材料的相变。结果表明，TaC在低于β-SiC的温度下开始结晶。特别值得指出的是，独特的核壳结构TaC @ C纳米颗粒是原位的在1400°C退火后形成并均匀分布在陶瓷基体中。即使在1600°C的高温下，β-SiC和TaC的晶粒尺寸也小于30 nm，满足了纳米复合材料的定义。与SiC-TaC-C纳米复合材料有关的本研究为富集适用于恶劣环境中的结构/功能应用的超高温陶瓷家族开辟了一条新道路。