Synthesis of bamboo-like SiC whiskers from waste silica fume

摘要

A process for the utilization of wasted silica fume is proposed in this work. Silicon carbide (SiC) whiskers several tens of micrometers in length and with a bamboo-like morphology have been successfully synthesized by a carbothermal reduction process using purified silica fume as the silicon source. The morphology and structure of SiC whiskers were investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. Studies found that the assynthesized whiskers were grown as single-crystalline β-SiC along the (111) growth direction. The whiskers consisted of hexagonal stems randomly decorated with larger-diameter knots along their whole length. On the basis of the characterization results, a vapor–solid process was discussed as a possible growth mechanism of the β-SiC whiskers.