High-temperature phase stability of Y2O3 and SiO2 co-doped ZrO2 powder

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 degrees 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 degrees C. Increasing the ratio (1:4 to 4:1) of SiO2 substitution Y2O3 will reduce the tetragonality of the powder at 1300 degrees 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. [GRAPHICS] .