Synthesis and characterization of SiC ultrafine particles by means of sol-gel and carbothermal reduction methods

A modified sol–gel method is proposed for the preparation of silicon carbide ultrafine powders. In this method, tetraethoxysilane (TEOS) and saccharose are used for preparing a binary carbonaceous silicon xerogel, and ferric nitrate is employed in the sol–gel process as a catalyst. The influence of processing parameters such as temperature of reaction and mass ratio of C to Si (C/Si =0.5, 0.7, 1) on the synthesis of SiC particles were studied. After purification, the SiC sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectrum, Fourier transform infrared spectroscopy, differential thermal analysis (DTA) and thermo- gravimetric analysis (TGA). The results show that the SiC ultrafine particles were fully formed at reaction temperature of 1450 °C by employing the mass ratio of C/Si =1. This is confirmed by the obtained pattern from XRD and the Si–C absorption bands of SiC in the FTIR.