Effect of liquid-forming additives on the sintering and mechanical properties of Al2O3/3Y-TZP (30 vol.%) composite

Al2O3/3Y-TZP (30 vol.%) composite was pressurelessly sintered with addition of TiO2MnO2 and/or CaO-Al2O3-SiO2 glass. It was found that TiO2-MnO2 addition greatly enhanced the densification of the composite by the formation of a low-viscosity liquid at sintering temperature. In contrast, the high-viscosity liquid formed by CaO-Al2O3-SiO2 glass improved mechanical properties because of its repressing effect on grain growth. The composite could be obtained at a temperature as low as 1400degreesC by co-doping with TiO2-MnO2 and CAS glass. Bending strength of 552 +/- 64 MPa and fracture toughness of 6.03 +/- 0.22 MPa m(1/2) were obtained with a doping level of 2 wt.% TiO2-MnO2 and 2 wt.% CAS glass. (C) 2002 Elsevier Science Ltd. All rights reserved.