High‐Emperature Thermal Conductivity of Alumina‐Reinforced Zirconia Composites

10-mol% yttria-stabilized zirconia (10YSZ) - alumina composites containing 0-30 mol% alumina were fabricated by hot pressing at 1500 °C in vacuum. Thermal conductivity of the composites, determined at various temperatures using a steady-state laser heat flux technique, increased with increase in alumina content. Composites containing 0, 5, and 10-mol% alumina did not show any change in thermal conductivity with temperature. However, those containing 20 and 30-mol% alumina showed a decrease in thermal conductivity with increase in temperature. The measured values of thermal conductivity were in good agreement with those calculated from the Maxwell-Eucken model where one phase is uniformly dispersed within a second major continuous phase.