Macroporous silicon carbide ceramics with porosities ranging from 67% to 84% were fabricated by a carbothermal reduction process from a carbon-filled polysiloxane and subsequent annealing. Microstructural development during annealing was investigated using scanning electron microscopy (SEM). The grain size increased with an increase in the annealing time and the morphology changed from equiaxed to cube or hexagonal platelets depending on the annealing temperature. By controlling the annealing time and annealing temperature, it was possible to adjust the size and morphology of SiC grains in macroporous SiC ceramics.

Keywords: porous ceramics, silicon carbide, microstructure, porosity, carbothermal reduction.