Resistivity‐Microstructure Relations in Lithia‐Stabilized Polycrystalline β”‐Alumina

The sodium ion resistivity of lithia‐stabilized polycrystalline β”‐alumina was measured as a function of temperature for fine‐grained and coarse‐grained specimens with a chemical composition of 8.80 Na 2 0‐0.75 Li 2 O‐90.45 A1 2 O 3 (wt%). A model is presented which explains the dependence of sodium ion resistivity on grain size. Using the model the activation energy was determined for the transport of sodium ions across a grain boundary in this form of sodium β”‐alumina.