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 Al ₂ O ₃ were investigated. Specimens with 0.5 and 1 mol% Al ₂ O ₃ maintained the cubic phase, and the thermal diffusivity increased from 0.499 to 0.661 mm ² /s with a 1 mol% addition. The addition of 5 mol% caused a decrease in the thermal diffusivity (0.609 mm ² /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 Al ₂ O ₃ . The ionic conductivity was increased up to the addition of 1 mol% due to scavenging of siliceous by Al ₂ O ₃ , while the 5 mol% addition showed a decrease in conductivity with the formation of the intergranular phase.