The Influence of Microstructure and Grain Boundary on the Electrical Properties of Scandia Stabilized Zirconia

Nanocrystalline Sc2O3 (different doping content) stabilized ZrO2 (ScSZ) powders are prepared by the hydrothermal method. Dense ScSZ ceramic pellets are fabricated by isostatically pressing then sintering at 1350 degrees C for 2 h. 8 mol% Sc2O3 doped Zirconia possesses the highest conductivity of all the samples measured by impedance spectroscopy. Different grain size of 8ScSZ samples which are observed by scanning electron microscopy (SEM) are prepared by sintering with different temperature and different hours. The correlation between grain size and electrical properties is analyzed by impedance spectroscopy fitting and calculating with brick-layer model and Mott-Shottky model: the total grain boundary conductivity decreases but the specific grain boundary conductivity increases with the decrease in grain size of 8ScSZ; the grain boundary space charge potential decreases and the concentration of oxygen vacancies in the space charge regions increases with decreasing grain size.