Preparation of SiC Porous Ceramics by Crystalline Silicon Cutting Waste

摘要

SiC porous ceramics were prepared at 1 400 ℃ for4 h with crystalline silicon cutting waste and activated carbon as main starting materials and NH_4HCO_3 as the pore-forming agent. Effects of NH_4HCO_3 additions( 0,20%,30%,40%,by mass) on the phase composition,microstructure,sintering properties,cold compressive strength and thermal shock resistance of as-prepared Si C porous ceramics were investigated. The results show that:( 1) addition of NH_4HCO_3 remarkably influences the apparent porosity and cold compressive strength of specimens. The apparent porosity achieves its maximum value( 63. 40%) when 40% NH_4HCO_3 is added,while the minimum cold compressive strength is 4. 77 MPa;( 2) the specimen with 40% NH_4HCO_3 has the best thermal shock resistance. The thermal cycling times between1 000 ℃ to room temperature reach 62;( 3) the addition of NH_4HCO_3 does not remarkably affect the phase composition of the specimens;( 4) the specimens include a large number of SiC particles and a small amount of SiC whiskers.