CONDUCTIVITY OF BETA-ALUMINA AND ITS DEPENDENCE ON SODIUM AND MAGNESIUM CONTENT

The relationship between conductivity and sodium content has been investigated for sintered beta-alumina containing MgO. Conductivities of 3. 5 multiplied by 10** minus **3, 8. 0 multiplied by 10** minus **3, and 4. 4 multiplied by 10** minus **3 ohm** minus **1-cm** minus **1 were found for material containing 1, 2, and 4% MgO, respectively, with optimum sodium content. Experimental conductivities for 1 and 2% MgO agree well with calculated values assuming one additional sodium ion for each magnesium ion present. Resistance measurements were made in the frequency range 0. 75-10kHz, and conductivities were calculated from resistances extrapolated to infinite frequency. Electrode contact was made using thin films of silver and gold following glow discharge cleaning techniques.