Analysis of silicon carbide particle formation process from carbon black-phenolic resin-ethyl silicate hybrid precursors

Abstract

Precursors for silicon carbide spherical particles were prepared from liquid mixtures of spherical carbon black, phenolic resin and ethyl silicate. After the gelation, drying and pyrolysis at 1273 K, carbon-silica hybrids were obtained with C/SiO2 ratios in 2.77-2.98. In these pyrolyzed materials, a part of the carbon existed as carbon black dispersed in the matrix. The other carbon, which originated from phenolic resin, was located in the surrounding matrix area. These C-SiO2 hybrids were heat-treated at 1838 K in an Ar gas flow to obtain SiC particles with carbothermic reduction process. The conversion process of the hybrids to SiC was monitored by thermogravimetric analysis. The influence of the carbon black content on conversion rates, residual amounts of excess carbon and the resulting SiC particle morphology were investigated.