Microstructure and mechanical properties of glass-infiltrated Al2O3/ZrO2 nanocomposites

This work was to investigate the effect of zirconia nanoparticles content on microstructure and mechanical properties of glass-infiltrated alumina/zirconia composites (AZGs). A series of slip-cast zirconia-toughened alumina (ZTA) compacts containing 10, 20, 30 wt% nano-zirconia, respectively, were partially sintered at 1,250°C for 2 h, then infiltrated with lanthanum borosilicate glass of lower thermal expansion at 1,180°C for 4 h. A porosity ranging from 21 to 25% mainly with submicron pore size was demonstrated in the partially-sintered ZTAs. Homogeneous distribution and micro-crystallization of intergranular glass phase was showed in the AZGs. The mechanical strength and fracture toughness of AZGs increased with zirconia content, the maximum (633.5 ± 41.7, 6.7 ± 0.6 MPa m^0.5) were obtained in 30 wt% zirconia group, which were significantly higher than those in 10 wt% zirconia group (P < 0.05). The improved mechanical performance of AZGs containing 30 wt% zirconia was attributed to their larger zirconia content as well as thinner intergranular glass film.