Synthesis and in situ growth mechanism of SiO2@SiC core–shell nanocomposite

Abstract

With the aim at modifying SiC and simplifying the manufacturing process, many kinds of SiC matrix composites have been designed. In this work, the SiO2@SiC core–shell composites were synthesized via carbon thermal reduction process. The precursors were prepared from polyvinylpyrrolidone (PVP) and SiO2 spheres with different particle sizes. The viscosity of PVP solution plays a significant role in the formation of core–shell structure. After calcining at 1350 °C, the SiC layer was in situ formed on amorphous SiO2. An extensible liquid–solid–vapor growth mechanism is proposed basing on the characterization results as well as the possible reactions among the solid phases, liquid phases with a certain viscosity and intermediate gas phases. Moreover, this kind of nanocomposites was believed to have a great potential in the electromagnetic wave absorbing material and photocatalytic reactor application.