Porous SiC Ceramics with Multiple Pore Structure Fabricated via Gelcasting and Solid State Sintering

Porous SiC ceramics with multiple pore structures were fabricated via gelcasting and solid state sintering. A novel gelling agent of Isobam was applied and PMMA was used as both foam stabilizer and pore forming agent. The mechanical properties of porous SiC ceramics were investigated as functions of PMMA content, rotating speed of ball mill, and sintering temperature. With PMMA content increasing from 5wt% to 20wt%, the foaming effect was inhibited while the stability of bubbles increased. When the rotating speed was 220 r/min, the open porosities of the as-prepared SiC ceramics sintered at 2100 varied from 51.5% to 72.8%, and compressive strength varied from 7.9 to 48.2 MPa. With the rotating speed increasing from 220 to 280 r/min, the foaming effect was aggravated and the porosities of SiC ceramics sintered at 2100 increased. While the sintering temperature increasing from 2050 to 2150 , the SiC ceramics prepared with PMMA content of 20wt% at rotating speed of 220 r/min decreased in the open porosities while increased in compressive strength.