Thermal Stability and Ionic Conductivity of Calcia-Stabilized Zirconia with Alumina Addition

The thermal expansion and ionic conduction of 15 mol% CaO-stabilized zirconia (CSZ) with added Al2O3 were investigated. Specimens with 0.5 and 1 mol% Al2O3 maintained the cubic phase, and the thermal diffusivity increased from 0.499 to 0.661 mm2/s with a 1 mol% addition. The addition of 5 mol% caused a decrease in the thermal diffusivity (0.609 mm2/s) with the formation of the monoclinic phase. The thermal expansion coefficient of the CSZ decreased, and the thermal diffusivity increased with the addition of Al2O3. The ionic conductivity was increased up to the addition of 1 mol% due to scavenging of siliceous by Al2O3, while the 5 mol% addition showed a decrease in conductivity with the formation of the intergranular phase.