Structural evolution and phase transformation behaviors of 10 wt. % dysprosia stabilized zirconia ceramic powders

In this study, dysprosia stabilized zirconia (DySZ) powders were synthesized using an improved cocurrent coprecipitation method. The phase compositions and structures before and after heat treatment, as well as the phase transformation behaviors of 10DySZ powders were investigated. Results show that the nano-sized powders were synthesized with metastable tetragonal-phase structure and embed with some polygonal young crystals. After phase transformation in the range of 1300-1400 degrees C, the products display a consistent equilibrium composition, including approximate equal content of c- and m-DySZ, as well as trace Dy2Zr2O7, which was mainly determined by the addition amount of Dy stabilizer. The formation of phase transformation products can be attributed to the segregation of Dy3+ ions. Moreover, the phase transformation process was confirmed to be abide by the new phase nucleation and growth theory based on the fitting Avrami constants. The elevated ambient temperature has a significant influence in accelerating the phase transformation of DySZ, as well as advancing the conversion of dominated step during the phase transformation process.