XU Xu, LUO Linghong, CHENG Liang, SUN Liangliang, SHI Jijun, WU Yefan
(School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333403,Jiangxi, China)
Abstract: The segregation of impurities on the grain boundary in solid state ionic conductor can significantly affects the ionic conduction property. In this work, 10.93 wt.% Sc2O3 and 1.38 wt.% CeO2 doped ZrO2 (SSZ) powder was used as raw materials to be sintered at 1300 ℃, 1400 ℃, and 1500 ℃ respectively to prepare electrolyte plates. The grain size of the sintered samples was calculated based on Rietveld refinements of X-ray diffraction patterns. The evolution of grain resistance, grain boundary resistance and total resistance along with the increased testing temperatures and grain size was investigated using AC impedance method. Also,the grain, grain boundary, and total conductivity activation energy was respectively derived from the results of AC impedance testing.The grain boundary resistance decreased with the increase of grain size due to the decreased volume fraction of grain boundary,whereas the possible impurity segregation at grain boundary was found to be some compensation for the decrease of grain boundary resistance.
Key words: solid ionic conductor; Sc2O3 stabilized ZrO2; AC impedance spectroscopy; rietveld refinement; grain boundary conductivity