Alkali Ion Conductivity in Fused Silica

Abstract

The alkali ion conductivity of fused silica was measured between 350°C and 500°C using fused nitrate salts for electrodes. Within this temperature range the conductivities of these ions are linear with reciprocal temperature and the activation energies for sodium, lithium, and potassium conduction are 28.1, 34.7, and 32.0 Kcal/mole respectively. Chemical analyses have shown that sodium and lithium can be electrolyzed from silica in this temperature range but potassium cannot. The measurements have suggested that when the mole fractions of sodium and lithium are almost equal and the ions are homogeneously distributed, the conductivity exhibits a behavior similar to the mixed alkali effect.