The interface between an ionic conductor and a neighboring solid phase was considered. The equilibrium situation was first presented. The interface was divided into core and space charge region, and it was assumed that the material parameters (such as defect standard potentials and mobilities) behaved as step functions. Interaction with an insulator or a parent metal, as a second phase, was briefly considered. On the basis of the equilibrium situation, the interfacial impedance was modelled in a novel manner. The interfacial resistance was derived analytically, and an exact method was proposed for the calculation of the space charge capacitance. A new experimental impedance technique was also presented which was especially sensitive to the interfacial response and permitted scanning of the electrical properties, from the boundary to the bulk, by changing the frequency.

J.Jamnik, J.Maier, S.Pejovnik: Solid State Ionics, 1995, 75, 51-8