Polyurethane foam was used as a precursor for fabricating SiC-based ceramic foam filters. Two recoating slurry processes were adopted to enhance the strength of ceramic foam. One was the recoating slurry of stoved green body and another was the recoating slurry of pre-sintered green body. The differences in weight increase and thermal shock resistance of ceramic foams fabricated by the two recoating slurry processes were investigated. The effects of pre-sintering temperature on weight increase and thermal shock resistance are discussed. Thermal shock resistance of ceramic foams fabricated by two recoating slurry processes is lower than that by the single coating slurry process. Compared with recoating slurry of pre-sintered green bodies, with the same slurry, the weight increase of ceramic foams fabricated by recoating slurry of the stoved green bodies is less, but the number of thermal cycles to failure is much higher. For ceramic foams fabricated by recoating slurry of pre-sintered green bodies with the same slurry, the weight increase and the number of thermal cycles to failure decreased with the pre-sintering temperature.

Keywords: Engineering ceramics; Sintering; Thermal shock; Recoating; Slurry