Y₂O₃ and SiO₂ co-doped ZrO₂ powders with various additions of SiO₂ substitution Y₂O₃ have been prepared by co-precipitation method. The microstructure, phase and chemical composition, phase transformation process, and phase stability after repeated calcination at 1300 °C of these powders have been investigated. The main phase of all powders is t′-ZrO₂. There is no phase transformation when the powders are heated from room temperature to 1400 °C. Increasing the ratio (1:4 to 4:1) of SiO₂ substitution Y₂O₃ will reduce the tetragonality of the powder at 1300 °C. The amorphous SiO₂ will inhibit the growth of grains to a certain extent during the calcination process. The increase of the substitution ratio of SiO₂ for Y₂O₃ will lead to the m-ZrO₂ more stable and the t′-ZrO₂ more unstable. The relationship among the SiO₂ substitution Y₂O₃ addition, phase composition, and high-temperature phase stability of the powders has been discussed.

Graphical abstract