Synthesis of controllable particle size SiC nanoparticles based on domain theory

Abstract

The study indicated that the phenolic resin pyrolysis carbon showed a gradual decrease in microdomain and domain sizes, as well as inter-domain compactness with increasing carbonization temperature (1200–1600 °C) and time (1–3 h). We determined that with an increase in carbonization temperature and time, the reduction and disappearance of organic groups such as CC, CH2, and C–O–C led to a gradual transformation of carbon microcrystals from structures of a larger size, with a certain curvature of more defects to smaller short straight shapes with fewer defects. This also led to a tendency of assimilation within the domains, an increase of inter-domain differences, and difficulty of further merging and growing smaller microdomains and domains. The β-SiC nanoparticles with a controllable particle size in the range of 30–200 nm, as well as controllable dispersibility, were successfully synthesized by reacting the coke with silicon. With further heat treatment at 600 °C for 6 h in air, the wrapped 2.0–3.6 nm amorphous phase homogeneous structure silicon oxide film was prepared on the SiC nanoparticles surface, which improved the oxidation resistance of the SiC nanoparticles. We determined that the reduction in microdomain and domain sizes, and an increase in inter-domain grain boundary defects, was one of the main reasons for promoting the exfoliation of microdomain and domain structures during the synthesis process to generate dispersed single smaller SiC nanoparticles.