Structure and transport characteristics of single crystals of zirconia stabilized by scandia and co-doped with terbium oxide

The effect of doping with Tb2O3.5 on the phase composition, structure and transport characteristics of ZrO2 - Sc2O3 solid solutions has been studied. Single crystals of (ZrO2)1-x-y(Sc2O3)x(Tb2O3.5)y solid solutions, where (x = 0.08–0.10; y = 0.01–0.02), were grown by directional crystallization of the melt in a cold crucible. The phase composition and structure of crystals were studied by X-ray diffraction, Raman spectroscopy, optical and transmission electron microscopy. The electrical conductivity of single crystals was measured by impedance spectroscopy. It is shown that the stabilization of the pseudocubic t″-phase in crystals containing 8 mol% Sc2O3 observed at the addition of 2 mol% Tb2O3.5. The introduction of 1 mol% Tb2O3.5 into crystals containing 9 and 10 mol% Sc2O3 also leads to the formation of the t″ -phase. The conductivity of crystals with a pseudocubic t″ structure depends on both the total concentration of stabilizing oxides and the Tb2O3.5 content. The (ZrO2)0.9(Sc2O3)0.09(Tb2O3.5)0.01 single crystals had the maximum conductivity over the entire temperature range.