Investigation of Electrical and Mechanical Properties of Tetragonal/CubicComposite Electrolytes Prepared by Impregnation of 8YSZ with Zirconia Solution

摘要

Zirconia solid electrolytes with nonequilibrium compositestructure were prepared by impregnation of a porous 8YSZ matrixwith a solution of Zirconia. Microstructures were characterized byXRD and SEM. The electrical properties were studied byimpedance spectroscopy as a function of temperature. Biaxialflexural strength and fracture toughness of composite samples weremeasured by ring on ring and Vickers microhardness indentationmethods respectively. The microstructures of the compositeelectrolytes were composed of cubic grains surrounded bytetragonal second phase grains. It was shown that the electricaland mechanical properties of the prepared electrolyte can beadjusted by controlling the amount of doped zirconia. Increasingthe amount of doped zirconia increases the tetragonal phasecontent which improves fracture toughness and fracture strength.In addition, increasing tetragonal phase content of the compositeelectrolytes decreases the conductivity at high temperatures whilethe situation is reversed at low temperatures.