Crystal Structure and Electrical Properties of Magnesia Co-Doped Scandia Stabilized Zirconia

Abstract

Mg-doping effects on the crystal structure and ion conduction properties of Scandia Stabilized Zirconia have been studied in the (ZrO2)0.89(Sc2O3)0.11-x(MgO)x (0 ≤ x ≤ 0.07) system. The materials have been prepared by a sol-gel method. Characterization of the crystal structure has been carried out by means of X-ray diffraction, Raman spectroscopy, synchrotron X-ray diffraction, selected area electron diffraction and high resolution transmission electron microscopy. Cubic phase-stabilization is observed in materials corresponding to x ≥ 0.03 but single cubic-phase formation is achieved only in (ZrO2)0.89(Sc2O3)0.08(MgO)0.03. Ionic conductivity of the oxides has been determined by complex impedance spectroscopy. Stabilization of the cubic phase in the compounds with x ≥ 0.03 values avoids rhombohedral-cubic phase transformation, improving the conductivity bellow 600°C compare to the one of 11ScSZ.