Preparation and Characterization of SiC Whisker-Reinforced SiC Porous Ceramics for Hot Gas Filtration

SiC porous ceramics (SCPCs) were fabricated by a dry press forming method and in situ reaction-bonding technique using ZrO2 as sintering aids, activated carbon as pore-forming agent, and SiC whiskers as reinforcing agent. The effects of the amount of SiC whiskers on the porosity, bending strength, microstructure, and gas permeability of the SCPCs were investigated. The results showed that without incorporated SiC whiskers, the bending strength was 9.7 MPa for the SCPCs sintered at 1550 °C, while the bending strength of the SCPCs with 3.3 wt % SiC whiskers reached 28 MPa, nearly a 3-fold increase in bending strength over that of pristine SCPCs. The SiC whiskers-enhanced ceramic supports exhibited a porosity of 44.2% and an average pore size of 14.6 μm. Moreover, the samples also showed a gas permeability of 270 m3/m2·h·kPa, which is 1.7 times higher than that of the pristine SCPCs. The bending strength remained high after 18 cold–hot cycles (800 °C), indicating good thermal shock resistance.