Preparation, structure and electrical conductivity of pyrochlore-type Gd_(1-x)Eu_(2x)Sm_(1-x)Zr_2O_7 ceramics with a constant lattice parameter

摘要

A novel series of Gd_(1-x)Eu_(2x)Sm_(1-x)Zr_2O_7 (x=0, 1/3, 1/2, 2/3, 1) ceramics with a constant lattice parameter are prepared by solid-state reaction, and are then evaluated as possible solid electrolytes. The microstructure and electrical properties of Gd_(1-x)Eu_(2x)Sm_(1-x)Zr_2O_7 ceramics have been investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and complex impedance analysis. Gd_(1-x)Eu_(2x)Sm_(1-x)Zr_2O_7 ceramics exhibit a single phase of pyrochlore-type structure. The total conductivity of Gd_(1-x)Eu_(2x)Sm_(1-x)Zr_2O_7 ceramics obeys the Arrhenius relation, and gradually increases with increasing temperature from 723 to 1173 K. At 973-1173 K, the composition has little effect on electrical conductivity of Gd_(1-x)Eu_(2x)Sm_(1-x)Zr_2O_7 ceramics. Gd_(1-x)Eu_(2x)Sm_(1-x)Zr_2O_7 ceramics are oxide-ion conductors in the oxygen partial pressure range of 1.0 × 10~(-4) to 1.0 atm at all test temperature levels. The maximum total conductivity of Gd_(1-x)Eu_(2x)Sm_(1-x)Zr_2O_7 ceramics is about 1.01 × 10~(-2) S cm~(-1) at 1173 K in air.