Oxidation bonding of porous silicon carbide ceramics with synergistic performance

Porous silicon carbide (SiC) ceramics were fabricated by an oxidation-bonding process, in which the powder compacts are heated in air so that SiC particles are bonded to each other by oxidation-derived SiO2 glass. It has been shown that a high porosity can be obtained by adding a large amount of graphite into the SiC powder compacts and that the pore diameter can be controlled by the size of graphite particles and/or SiC powders. When a 0.3-μm SiC powder was used, a high strength up to 133 MPa was achieved at a porosity of 31.5%. Moreover, oxidation-bonded SiC (OBSC) ceramics were observed to exhibit an excellent resistance to oxidation and thermal shock.