Influence of Co3O4 addition on the ionic conductivity and microstructural properties of yttria-stabilized zirconia (8YSZ)

Abstract In this study, 0 – 15 wt.% Co3O4 powders were added to 8 mol.% yttria-stabilized cubic zirconia (8YSZ) powders in order to determine the effect of Co3O4 addition and amount on the microstructure, sintering, and electrical properties of yttria-stabilized cubic zirconia. Colloidal processing was used to ensure uniform mixing of the powders and to obtain a homogeneous microstructure. X-ray diffraction results showed that the average lattice parameter of the yttria-stabilized cubic zirconia decreased from 5.146 A to 5.135 A upon Co3O4 addition, and that the lattice parameter did not change above a Co3O4 content of 1 wt.%. The initial decrease in the lattice parameter is attributable to the smaller ionic radius of Co3+ dissolved in the yttria-stabilized cubic zirconia matrix. The electrical conductivity of the specimens was measured using a frequency response analyzer in the range of 100 mHz – 13 MHz and 300 – 800 °C. Grain boundary conductivity of yttria-stabilized cubic zirconia was found to be enha...