Cross effects in solid media with diffusion

Based on thermodynamics of irreversible processes, possible cross effects in isothermal diffusion in solids with internal surfaces are analyzed. Expressions for the fluxes of components and for the fluxes of a newly introduced thermodynamic parameter, specific area of internal surfaces per unit volume or mass of the medium, are obtained. An analysis of these relations and relations between the stresses and strains for various cases is given. In derivation of the governing relations, it was assumed that diffusion proceeds through interstitial sites.