Fabrication of porous SiC/calcium hexaluminate composites

Porous SiC/calcium hexaluminate (CA6, where C = CaO and A = Al2O3) composites were successfully prepared via two steps: (i) preparation of green body by direct foaming combined with pure calcium aluminate cement curing method at room temperature and (ii) sintering by in-situ formed CA6 phase at relatively low temperature (1500 °C). The phase compositions, total porosity, compressive strength and the microstructure of porous SiC/CA6 composites with different composition and sintered at different temperatures were investigated. CA6 phase with plate-like morphology was the main bonding phase in the porous composites, and a compressive strength of 14.0 ± 0.6 MPa was achieved with a total porosity of 82.9%.