Analysis of properties of partially stabilized zirconia-doped Na + -beta-alumina prepared by calcining-cum-sintering process

Abstract To overcome the disadvantages of a conventional process, including its complex steps, Na+-β/β″-Al2O3 for use as a Na+-conductive solid electrolyte was prepared using a calcining-cum-sintering process. Further, to improve the sintering properties, partially CaO- or Y2O3-stabilized zirconia (CSZ or YSZ, respectively) was added as a sintering additive. To analyze the properties of the samples, the XRD patterns, sintered density, microstructure, and ionic conductivity of each partially stabilized zirconia (PSZ)-doped Na+-β/β″-Al2O3 specimen were investigated. The ionic conductivity of each specimen was measured using AC impedance spectroscopy, and the highest ionic conductivity of 1.3 × 10−1 S/cm was observed for the BA_3CSZ specimen. The specific resistance values of the PSZ-doped Na+-β/β″-Al2O3 specimens were approximately 7–10 Ω cm and were as good as those produced by the conventional process, with the exception of the BA_10CSZ specimen. The ionic conductivity of BA_10CSZ was significantly decreased, owing mainly to the formation of the secondary phase, Na4Ca3(AlO2)10.