Abstract

Uniformly BN-coated silicon carbide nanowires have been synthesized via the vapor–liquid–solid growth mechanism. Nanoscale Ni–C grains were used as catalysts and a mixture of boron and silica was heated to simultaneously generate SiO and B₂O₂ vapors. The uniform coating was explained based on the TEM observations. The fixed relative vapor concentrations absorbed by the catalyst droplets and the (111) facets at the outermost surface of the SiC nanowires are responsible for the uniform coating. The effect of the closely packed (111) plane, which exists on the surface of the nanowires, was studied for the tentative synthesis of BN-coated Si₃N₄ nanowires. The BN coating on Si₃N₄ nanowires is disordered due to the lack of a closely packed surface plane. When using a BN supported Ni catalyst, BN nanotubes and nano-bamboos, and crystalline straight or amorphous curved Si₃N₄ nanowires without BN coating are formed.