Structure and conductivity of yttria and scandia-doped zirconia crystals grown by skull melting

In this paper a detailed study of the (ZrO2)1-x(Y2O3)x (x = 0.025 – 0.15), (ZrO2)1-x(Sc2O3)x (x = 0.06 – 0.11) and (ZrO2)1-x-y(Sc2O3)x(Y2O3)y (x = 0.07 – 0.11; y = 0.01 – 0.04) solid solution crystals grown by skull melting technique is presented. The structure, phase composition, and ion conductivity of the obtained crystals were investigated by X-ray diffraction, transmission electron microscopy, Raman scattering spectroscopy, and impedance spectroscopy. Maximum conductivity as (ZrO2)1-x(Y2O3)x and (ZrO2)1-x(Sc2O3)x solid solution crystals is observed for the compositions containing 10 mol% stabilizing oxide, and the conductivity of 10ScSZ is ~3 times higher than for 10YSZ. Experiments on crystal growth (ZrO2)1-x-y(Sc2O3)x(Y2O3)y solid solutions showed that uniform, transparent crystals 7Sc3YSZ, 7Sc4YSZ, 8Sc2YSZ, 8Sc3YSZ, 9Sc2YSZ, 9Sc3YSZ, 10Sc1YSZ and 10Sc2YSZ are single phase crystal containing t’’ phase. It is established that a necessary condition of melt growth of (ZrO2)1-x-y(Sc2O3)x(Y2O3)y single-phase crystals is the total concentration of the stabilizing oxides from 10 to 12 mol%. The addition of Y2O3 affects the (ZrO2)1-x-y(Sc2O3)x(Y2O3)y solid solution conductivity different ways and depends on the Sc2O3 content in the starting composition. The effects of structure, phase composition, concentration and type of stabilizing oxides on the electrical characteristics of obtained crystals are discussed. This article is protected by copyright. All rights reserved.