Fabrication of macroporous silicon carbide ceramics by intramolecular carbothermal reduction of phenyl-bridged polysilsesquioxane

Abstract

Macroporous SiC ceramics were obtained from porous phenyl-bridged polysilsesquioxane prepared by a sol–gel method accompanied by spinodal decomposition subsequently subjected to intramolecular carbothermal reduction. By this method, we can obtain macroporous SiC ceramics with improved atomic-level homogeneity and controlled pore size more easily than by intermolecular carbothermal reduction using a mixture of SiO₂ and carbon powder. Therefore, the resultant SiC ceramics have sufficiently high purity without washing with hydrofluoric acid to remove residual SiO₂.