On the nonequilibrium thermodynamics of non-Fickian diffusion

Following the methods of extended irreversible thermodynamics, a set of coupled evolution equations are found for the diffusion flux and the viscous pressure tensor in a binary fluid mixture. The resulting equation for the diffusion flux reduces in some limiting cases to a relaxational Maxwell-Cattaneo equation or to a set of equations analogous to the ones used in the Thomas-Windle and the Durning-Tabor descriptions of cas II diffusion