Influence of Gd2O3 and Yb2O3 Co-doping on Phase Stability, Thermo-physical Properties and Sintering of 8YSZ

The role of multicomponent rare earth oxides in phase stability, thermo-physical properties and sintering for ZrO2-based thermal barrier coatings (TBCs) materials is investigated. 8YSZ co-doped with 3 mol(Gd2O3 and 3 mol% Yb2O3 (GYb-YSZ) powders are synthesized by solid state reaction for 24 h at various temperatures. As temperature increases, stabilizers are dissolved into zirconia matrix gradually. Synthesized at 1 500 °C, GYb-YSZ is basically composed of cubic phase. GYb-YSZ exhibits excellent phase stability and sinters lower than 8YSZ by nearly three times. The thermal conductivity of GYb-YSZ is much lower than that of 8YSZ, and the thermal expansion coefficient of GYb-YSZ is comparable to that of 8YSZ. The influence of Gd2O3 and Yb2O3 co-doping on phase stability, thermal conductivity and sintering of 8YSZ is discussed.