Thermal shock resistance of in situ formed Si2N2O–Si3N4 composites by gelcasting

Thermal shock resistance of Si2N2O–Si3N4 composites was evaluated by water quenching and subsequent three-point bending tests of strength diminution. Si2N2O–Si3N4 composites which was prepared with in situ liquid pressureless sintering process using Yb2O3 and Al2O3 powders as sintering additives by gelcasting showed no macroscopic cracks and the critical temperature difference (ΔTc) could be up to 1400 °C. A mass of pores existed in the sintered body and the irregular shaped fibers extended from the pores increased the thermal shock property.