Fabrication and microstructure of liquid sintered porous SiC ceramics through spark plasma sintering

6H-SiC porous SiC ceramics accompanied by the formation of large clubbed and tabular grains were successfully fabricated at 1800 °C under an applied pressure of 50 MPa for 5 min by spark plasma sintering technique without introducing any pore-creating agent. The phase composition, microstructure and properties of porous SiC ceramics were investigated. The measured porosity of the specimens was 35.7% and the mean pore size varied in the range of 0.3-3 μm. The sintered specimen had a strength of 103 MPa, a fracture toughness of 2.89 MPam1/2, and a density of 1.85 g/cm3. The mechanisms of porous structure and grain growth were elucidated.