Polymer precursor synthesis of novel ZrC-SiC ultrahigh-temperature ceramics and modulation of their molecular structure

In this study, ZrC-SiC composite ceramics were prepared with varying Zr/Si molar ratios using sol-gel method. Composites were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, and energy-dispersive X-ray spectroscopy (EDS). FT-IR analysis confirmed macromolecular network structure of composites, in which the precursor is composed of polyvinyl butyral (PVB) as main chain, silane molecules are interlinked via -OH moieties in PVB side chains, and Zr atoms are crosslinked with Si in corresponding proportion. Ceramic precursor begins to decompose at a temperature exceeding 1300.C and is completely transformed into ZrC-SiC composite ceramics with corresponding Zr/Si molar ratio at 1600.C. Raman spectroscopy and TEM results reveal that after annealing at 1600.C, ZrC powder uniformly covers surface of SiC ceramics, and high-crystallinity graphite carbon covers ZrC powder.

Automated summary

ZrC-SiC composite ceramics with varying Zr/Si molar ratios were prepared using sol-gel method. The composites were characterized by various techniques including FT-IR, XRD, TGA, TEM, SEM, Raman spectroscopy, and EDS. The results showed the formation of a macromolecular network structure in the composites, with Zr atoms crosslinked with Si in corresponding proportion. After annealing, ZrC powder uniformly covered the surface of SiC ceramics, with high-crystallinity graphite carbon covering the ZrC powder.