Silicon carbide nanostructures from reactions between vapors of organochlorosilanes and liquid of sodium-factors affecting morphology and composition

Abstract

Cubic shells and spherical nanoparticles of beta-SiC were produced at 1273 K by processing the ceramic precursors formed from the reactions between vapors of organochlorosilanes, Me2SiCl2, MeSiCl3, MeSiHCl2, and PhSiCl3, and liquid Na at 523-723 K. From Me2SiCl2, a flexible linear polycarbosilane precursor was synthesized and covered the NaCl byproduct surface to form a cubic shape. Hollow cubic beta-SiC shells were produced after the NaCl templates were removed. From MeSiCl3, a rigid cross-linked polycarbosilane was produced and phase segregated from the NaCl byproduct. The precursor was transformed into nanoparticles without special morphology. MeSiHCl2 produced a cross-linked polysilane precursor at low temperatures, which can be converted into a mixture of beta-SiC and Si nanoparticles. At high temperatures, the polysilane converted to polycarbosilane and produced hollow cubic beta-SiC shells. The carbon-rich PhSiCl3 generated cube-like particles as the final product, which contained beta-SiC and carbon.