Diffusion, Drift and their interrelation through Volume Density

Marek Danielewski (1) , Bartek Wierzba (2)

1 Physical Chemistry of Solids
2 Physical Chemistry of Solids

The evolution of the understanding of the mass transport phenomena in solids and liquids reduce the gap between these continua and allow for the unification of phenomenological models. We consider the central Darken problem of the choice of the coordinate axes for diffusion. Namely, the definition of this mode of motion and the method how diffusion displacement is defined and measured. In our analysis we extensively use the Euler's and Liouville theorems. We derive the formula of volume density conservation, i.e., the volume continuity equation. This fundamental formula defines the volume-fixed frame of reference in the multicomponent, solid, gas and liquid solutions. The volume fixed frame of reference is self-consistent with the foundations of linear irreversible thermodynamics except recognizing the need to add volume density to the usual list of extensive physical properties undergoing transport in every continuum. Proposed modifications are self-consistent with the literature dating back to Onsager, the experiments of Kirkendall, their interpretation by Darken and recent generalized formulations. It will be shown that the method can be used in mechano-chemistry and electro-mechano-chemistry.

Mots clés: Physical Sciences

Marek Danielewski, Bartek Wierzba. Diffusion, Drift and their interrelation through Volume Density. Philosophical Magazine, 2009, 89 (04), pp.331-348. ⟨10.1080/14786430802620732⟩. ⟨hal-00514006⟩