Synthesis and high-temperature phase transformation behavior of Dy2O3–Sc2O3 co-stabilized ZrO2 powders prepared by cocurrent chemical coprecipitation

Abstract

In this study, Dy2O3–Sc2O3 co-stabilized ZrO2 (DyScSZ) powders with various stabilizer ratios were synthesized by cocurrent chemical coprecipitation method. The difference analysis of phase composition and microstructure was conducted on the synthesized powders in detail. The phase evolution and phase transformation behaviors of the synthesized powders were also investigated. Results show that all of the powders were synthesized with nanoscale and exhibit subglobose morphology. The excessive elevation of Sc2O3 fraction in total stabilizers was adverse to the formation of the synthesized powders with pure tetragonal phase, which also exhibit a significant effect both on the phase transformation behaviors and the final volume fractions of transform products. The 2.5Dy1.0ScSZ powders exhibit favorable phase stability resulting from the nano-size effect and the synergies of Dy2O3 and Sc2O3 stabilizers during the phase transformation process. Moreover, a phase transformation mechanism of DyScSZ was proposed based on the new phase nucleation and growth theory.