Thin interphase/imperfect interface in conduction

Thin interphase between two media is modeled in terms of imperfect interface conditions in the context of potential theory, thus for conduction, dielectric behavior, and permeability. There is no limitation on the magnitude of interphase material conductivity. The imperfect interface conditions involve interface discontinuities of potential and normal component of flux. The theory is tested by application to the boundary value problem of a coated inclusion and to evaluation of effective conductivity of composites with coated spherical particles. Very accurate agreement with three phase solutions of those problems is obtained.