Formation of spherical nanocrystalline silicon carbide via carbothermal reduction of water glass and sugar

A simple method was developed to synthesise spherical nanocrystalline silicon carbide via carbothermal reduction of water glass and sugar. The overall process is composed of three steps: the preparation of spray dried precursors, carbonisation of the precursors and carbothermal reduction. The precursors and products were characterised by XRD, infrared, Brunauer-Emmett-Teller, SEM and TEM. The results show that carbothermal reduction of the precursors could be completed at 1500 degrees C for 2 h. The as prepared product is spherical nanocrystalline beta-SiC powders with the diameter about 13.6 nm and the BET specific areas of 17 m(2) g(-1). In addition, the powder is of high purity, because sodium oxide in the precursor could be eliminated by the escape of sodium at high temperature.