Elucidation of bifurcation of the Kirkendall marker plane in a single phase using physico-chemical approach

The complete understanding of the phenomenological process related to the bifurcation of the Kirkendall marker plane is still lacking. In this study a physico-chemical approach is used to elucidate this behavior in a single phase of β-NiAl and to calculate the diffusion parameter at the Kirkendall marker planes in the interdiffusion zone. To apply the physico-chemical approach, Ni- and Al-rich part of the phase is treated as two different phases and the plane corresponding to equiatomic composition is considered as virtual interface between them. Possible dissociation and reaction equations are considered to combine with the flux equations to derive the relation for diffusion coefficient.