Abstract

Several methods have been employed to synthesize SiC nanowires. The methods include heating silica gel or fumed silica with activated carbon in a reducing atmosphere, the carbon particles being produced in situ in one of the methods. The simplest method to obtain β-SiC nanowires involves heating silica gel with activated carbon at 1360 °C in H₂ or NH₃. The same reaction, if carried out in the presence of catalytic iron particles, at 1200 °C gives α-Si₃N₄ nanowires and Si₂N₂O nanowires at 1100 °C. Another method to obtain Si₃N₄ nanowires is to heat multi-walled carbon nanotubes with silica gel at 1360 °C in an atmosphere of NH₃. In the presence of catalytic Fe particles, this method yields α-Si₃N₄ nanowires in pure form.