Phase composition, structure and properties of (ZrO2)1−x−y(Sc2O3)x(Y2O3)y solid solution crystals (x=0.08–0.11; y=0.01–0.02) grown by directional crystallization of the melt

Abstract

For the first time crystals of the (ZrO2)1−x−y(Sc2O3)x(Y2O3)y solid solutions (x=0.08–0.11; y=0.01–0.02) have been grown by directional melt crystallization. We have determined the range of melt compositions for which growth from the melt produces of the (ZrO2)1−x−y(Sc2O3)x(Y2O3)y solid solution single crystals. The single-phase optically transparent single crystals following composition were grown: (ZrO2)0.9(Sc2O3)0.08(Y2O3)0.02; (ZrO2)0.89(Sc2O3)0.09(Y2O3)0.02; (ZrO2)0.89(Sc2O3)0.10(Y2O3)0.01; (ZrO2)0.88(Sc2O3)0.10(Y2O3)0.02. Comprehensive study of the crystal structure by using XRD, transmission electron microscopy, and Raman spectroscopy revealed that the all single crystals, which is identified by XRD data as cubic one, in fact have t″ tetragonal structure, which forms by small displacement of oxygen ions along the c-axis. Data on the phase stability of the crystals during mechanical crushing were obtained. The electrical conductivity was measured as a function of temperature by electrochemical impedance spectroscopy. It is established that (ZrO2)0.89(Sc2O3)0.10(Y2O3)0.01 crystals have the highest conductivity (0.168S/cm at 1173K).