期刊
JOURNAL OF ADVANCED CERAMICS
卷 9, 期 3, 页码 320-328出版社
SPRINGER
DOI: 10.1007/s40145-020-0371-z
关键词
polymer-derived ceramics; TaC; SiC; nanocomposites; core-shell structure
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 degrees C, amorphous ceramic powders were obtained. The 900 degrees C ceramics were annealed at different temperatures in the range of 1200-1600 degrees 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 beta-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 degrees C. Even at a high temperature of 1600 degrees C, the grain sizes of beta-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.
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