Space charge regions in solid two-phase systems and their conduction contribution-I. Conductance enhancement in the system ionic conductor-'inert' phase and application on AgC1:Al2O3 and AgC1:SiO2

Abstract

The space charge contribution to the conductance is calculated for two-phase systems (bicrystal and dispersion) where the second phase is a 'chemically inert' phase such as alumina and silica. A great effect is to be expected if the second phase is surface reactive so that the mobile ion is stabilized or destabilized at the interface As a consequence, mobile ions are sucked out of the volume or driven into it, resulting in an enhancement of the concentration of vacancies or interstitials, respectively The derived equations, which describe the problem quantitatively, agree very well with experimental results in the AgCl Al2O3 and AgCl SiO2 systems and are also applied to literature examples With further investigations in mind, the maximum conductivity effect of such surface induced defects in a given two-phase system is estimated. © 1985.