Synthesis of porous silicon carbide from cellulose fibre templates infiltrated with polycarbosilane

Amorphous silicon carbide (SiC) with a stable porous structure was synthesised using a cellulose fibre preform (ash less filter paper) infiltrated with poly(methyl-carbosilane) and heated to 1000 degrees C, first under N-2 and then air. Scanning electron microscopy and Hg porosimetry confirmed the structure and porosity of the preform was largely reproduced in the final material; the porosity of the untreated template (72.4%) decreased following pyrolysis (58.1%) and then increased after treatment in air (80.0%). The SiC yield, inferred from thermogravimetric analysis of the infiltrated template, was linearly correlated with the number of infiltration steps and ranged between 3 and 21 wt-% for one and five infiltrations respectively.