Preparation of biomorphic porous SiC and SiO₂ ceramics by sol infiltration into biotemplate followed by controlled sintering

This study investigated the preparation of biomorphic porous silicon carbide (SiC) and silica (SiO₂) ceramics by controlled atmosphere heat treatment of silica sol infiltrated Gymnosperm pine wood derived carbon precursor. The SiO₂ -infiltrated carbon preform was heat-treated in the temperature range 1450–15,500 C in flowing argon and under vacuum to obtain porous SiC ceramics. The porous SiO₂ ceramic was obtained by heat-treatment of silica sol infiltrated C template in air at 1385^oC for 4 h. The effect of ceramization condition, the reaction mechanism, morphology of the porous ceramics and their phase composition were investigated. The grains of the microcellular SiC were found to be composed of nanocrystals and apparent crystallite size was found to be 123 nm.