Electrical Properties and Chemical Resistance of the Composites (1-x)Gd2Zr2O7·xMgO in Li-Containing Chloride Melts

Abstract

Composites of (1-x)Gd2Zr2O7·xMgO were prepared by mixing gadolinium zirconate with freshly precipitated Mg(OH)2 followed by heat treatment at 1500 °C. Small concentrations of magnesium oxide dissolved in the complex oxide matrix of Gd2Zr2O7. This led to decrease in the lattice parameters of the matrix phase and a complex redistribution of Gd and Zr over the A and B sublattices. According to the impedance spectroscopy results of the studied samples, for (1-x)Gd2Zr2O7·xMgO (x = 0.05, 0.07, 0.10), the ionic conductivity was slightly higher than that for the undoped Gd2Zr2O7. The share of dominant ion transport did not change upon doping with magnesium oxide. The composites showed chemical resistance in a lithium halide (LiCl) melt and interacted with LiCl-xLi2O (x = 2 wt.%, 4 wt.%) melts at 650 °C with the formation of a Gd2O3 phase or a mixture of phases (Gd2O3, Li2ZrO3, ZrO2, LiGdO2, or LiGdCl2) on the ceramic surface, respectively.