Low temperature degradation of Al2O3-doped 3Y-TZP sintered at various temperatures

The low temperature degradation of Al2O3-doped 3Y-TZP sintered at 1400–1600 °C was investigated by aging at 140 °C for various hours. X-ray diffraction and field emission scanning electron microscopy were used to study the microstructure of specimens. The results showed that the mean grain size of samples sintered at 1400–1600 °C was between 0.3 μm and 0.9 μm, addition of Al2O3 slightly promoted the coarsening of tetragonal grain during densification. Introduction of 0.5–5.0 wt% Al2O3 addition into 3Y-TZP effectively delayed the tetragonal-monoclinic phase transformation and the degradation of mechanical property during aging. Sintering temperature had a significant effect on the aging sensibility of 3Y-TZP. The aging resistance of 3Y-TZP decreased rapidly with the increase of sintering temperature, especially for the control group which is free of Al2O3 addition. This can be interpreted by the increase in grain size and the heterogeneous distribution of Y3+ ions within tetragonal grains.