Study of factors influencing the microstructure and phase content of ultrafine Y-TZP

2∼3.5 mol%Y2O3 stabilized zirconia powders were prepared by mixing pure zirconia and Y(NO3)3 solution. The sintering ability of these powders was investigated. The results show that with the increasing amount of yttria, the grain size decreases while the density and the (t+c)-ZrO2 phase fraction increase. It is not sufficient in stabilizing all the zirconia when the doped yttria is less than 2.5 mol%. Several experimental rules about the microstructure and phase content developing with sintering temperature and soaking time are presented. The critical grain size for the retention of high-temperature tetragonal phase in 3Y-TZP is about 0.5 μm. A 3Y-TZP sample with grain size about 0.3 μm, relative density higher than 99%, (t+c)-ZrO2 phase fraction more than 90%, was obtained when it was sintered at 1450 °C for 2 h in air.