Polymer-derived silicon carbide micro powders through selective solvent precipitation of high molecular weight polycarbosilane

Abstract

Synthetic route to β-SiC micro powders through selective solvent precipitation (SSP) of high-molecular-weight (HMF) polycarbosilane. (PCS) was developed. PCS (>3000 Da) was obtained through pyrolysis polycondensation of Polydimethylsilane. Spectral data confirmed that PCS could be fractionated and precipitated during the process without disturbing its molecular structure. Fractionated fine PCS powders were converted into crystalline β-SiC particles through ceramization at 1200–1450 °C under argon. XRD patterns revealed a strong and sharp peak at a diffraction angle of 35.8°, thereby confirm the β-SiC structure and purity. SEM analysis confirmed the particle morphology and aggregation of β-SiC particles. Particle size analysis results show that the SiC particles' size is in the range of 10–100 μm. Thermal data prove the high thermal stability of PCS-HMF. β-SiC particles were thermally inert up to 1000 °C and became reactive beyond 1000 °C.