| Abstract: | Intermetallic compounds containing high concentrations of structural vacancies have made the determination of the interdiffusivity from the composition profile from a diffusion couple a confusing issue. In this paper, an exact procedure is formulated from fundamental principles. The only assumption made is the use of the Gibbs–Duhem relation. We show that the standard procedure for analysing composition profiles in diffusion couples slightly overestimates the interdiffusivity. We also show that the procedure put forward by Kim and Chang (Metall. Mater. Trans., 31A () 1519) to analyse the composition profiles in NiAl is incorrect near the stoichiometric composition where it seriously underestimates the interdiffusivity. |
