Fabrication and properties of SiC porous ceramics using a polyurethane preparation process

Abstract SiC porous ceramics can be prepared by introducing the polyurethane preparation method into the production process of ceramic biscuits, followed by sintering at 1300 °C for 2 h under N2 flux after the cross-linking of polycarbosilane at 220 °C for 4 h in air. The microstructures, mechanical properties and infiltrations of the SiC porous ceramics are investigated in detail. The best dispersal effect comes from the SiC slurry with xylene as the solvent and a mixture of Silok®7096 (1 wt%) and Anjeka®6041 (4 wt%) as the dispersant. The compressive strength of SiC porous ceramics with high porosity (69.53%) reaches 16.9 MPa. The heat treatment can increase infiltration, the rate of which (4.296 × 10−7 mm2) after the heat treatment at 750 °C in air is approximately two times faster than that before the heat treatment. The SiC porous ceramics fabricated in this study will have potential application in active thermal protection systems.