The diffusion of Ti was studied within the framework of the Nernst-Planck theory of ionic diffusion. It was found that a concentration-dependent diffusivity arose naturally from the mathematical model, as a direct result of the electric field which was introduced by ion dislocation in the lattice. Numerical simulations of the 1-dimensional case furnished strong evidence for enhanced diffusive mass transport. It was suggested that this explained the anomalous lateral penetration of Ti, in this material, which had been observed in previous experiments.

F.D.Nunes, J.S.Andrade, J.M.Filho: Journal of Physics - Condensed Matter, 1994, 6[22], 4067-76