Fabrication of Mullite Fiber Reinforced SiC Porous Ceramic

Abstract

Ceramic fibers and whiskers have been used for modification of toughness because they increase fracture energy due to their high elastic modulus strength. The mechanism of this increase is well known to be pull-out, crack deflection and a bridging mechanism. This study focused on the increase in toughness, strength and thermal shock resistance when using mullite fibers in a gas filter for high temperatures. The green body uses the average 230μm particle diameter of SiC powders, which used as a skeletal material , the length to diameter ratio greater than 10 of the mullite fibers and the mixture of kaolin, feldspar and silica, which was used as a binder. The pore former be made up of graphite and active carbon. The molding pressure is 3MPa, and sintering temperature is 1300°C. The mullite fiber reinforced SiC porous ceramic has low filter pressure drop, 30.36% porosity and 35.66MPa flexural strength, which is higher than the SiC porous ceramic whitout mullite fibers. And the flexural strength degradation was only 5.4% after thermal shock tests.