It was noted that the concentration profiles that developed in a ternary diffusion couple during isothermal annealing could be analyzed directly for average ternary interdiffusion coefficients. A new analysis was presented for the determination of the average values, of the principal and cross-interdiffusion coefficients over selected regions of the diffusion zone, from an integration of the interdiffusion fluxes which were calculated directly from experimental concentration profiles. Average ternary interdiffusion coefficients, treated as constants, were calculated over composition ranges on either side of the Matano plane, and were examined for diffusional interactions among the diffusing components. The ternary interdiffusion coefficients which were determined from the new analysis were observed to be consistent with those determined by applying the Boltzmann-Matano analysis at selected compositions in the diffusion zone. The ternary interdiffusion coefficients were also used in analytical solutions, that were based upon error functions, for the generation of concentration profiles for the selected diffusion couples. The generated profiles were a good representation of the experimental profiles, including those which exhibited up-hill diffusion or zero-flux plane behavior in the individual components. The uncertainties in the values of the interdiffusion coefficients, as calculated using the new analysis, were found to be minimal.

A New Analysis for the Determination of Ternary Interdiffusion Coefficients from a Single Diffusion Couple. M.A.Dayananda, Y.H.Sohn: Metallurgical and Materials Transactions A, 1999, 30[3], 535-43