It was noted that, in diffusion-controlled interactions, the Kirkendall plane need not be unique. Multiple planes could develop, and sometimes the Kirkendall plane did not exist at all. A phenomenological approach was introduced in order to rationalize the Kirkendall-effect mediated migration of macroscopic inclusions within a diffusion zone.

Microstructural Stability of the Kirkendall Plane in Solid-State Diffusion. M.J.H.Van Dal, A.M.Gusak, C.Cserháti, A.A., F.J.J.Van Loo: Physical Review Letters, 2001, 86[15], 3352-5