THERMOELECTRIC-POWER STUDIES ON ALPHA-ALUMINA - SODIUM BETA-ALUMINA COMPOSITE ELECTROLYTE

In the context of electrical characterization of fast ionic conductors , there is an urgent need for thermoelectric power (TEP) measurements on new solid electrolyte materials. A composite electrolyte made of al pha-alumina and sodium beta-alumina which was used for monitoring very low oxygen potentials in the range of up to Al(l)/Al2O3, neither the electrical conductivity nor the TEP has hitherto been reliably reporte d. Hence; TEP measurements were carried out on the composite which yie lded an average value of 430 mu V/K over the temperature range 620 to 1250 K. From these data, an activation energy of 17.5 kJ mol(-1) was d erived for this exclusive sodium ionic conductor in its present form a s a composite.