Ionic conductivity of Na, K and Ag β″-alumina-ZrO2 composites

Composite samples of Na β″-alumina with 15 vol % Zr02 stabilized with 4.5 wt % Y2O3 were fabricated using two sintering schedules. K and Ag β″-alumina composites were prepared from the Na β″-alumina composite by ion exchange. The ionic conductivities of the Na, K, and Ag composites at 300 °C were 1.3×10−1, 5.9×10−2 and 6.8×10−3 S cm−1, respectively. K1c for the K composite was as high as 3.7 MPam1/2.