Fabrication and Mechanical Properties of Porous Silicon Carbide Ceramics from Silicon and Carbon Mixture

Silicon, carbon, and B4C powders were used as raw materials for the fabrication of porous SiC. beta-SiC was synthesized at 1500 degrees C in an Ar atmosphere from a silicon and carbon mixture. The synthesized powders were pressed into disk shapes and then heated at 2100 degrees C. beta-SiC particles transformed to alpha-SiC at over 1900 degrees C, and rapid grain growth of alpha-SiC subsequently occurred and a porous structure with elongated plate-type grains was formed. The mechanism of this rapid grain growth is thought to be an evaporation condensation reaction. The mechanical properties of the fabricated porous SiC were investigated and discussed.