Determination of Intrinsic Diffusion Coefficients in a Wide Concentration Range of a Cu–Ni Couple by the Multiple Markers Method

Directional electromigration-enhanced interdiffususion in the Cu–Ni system

“…16 Because of the increasing dominance of volume diffusion at higher temperatures, grain size effect becomes less important as the temperature of annealing is increased. Results of interdiffusion studies at a much higher temperature, 1000°C, were reported by Iijima et al over a wide range of copper concentrations 18 and compared to earlier results reported by Heumann and Grundhoff at the same temperature. 19 In Fig.…”

“…Such an apparent discrepancy might be reasoned by taking into account effects of vacancy motion and current-induced vacancy motion. Previous work on interdiffusivities and intrinsic diffusivity [18][19][20] shows that the intrinsic diffusivity of Cu D Cu , is higher than D Ni at all concentrations. Such a situation leads to preferential diffusion of one element and to the wellknown effects of Kirkendall shifts and Kirkendall porosity.…”

“…In the absence of a current, higher interdiffusivities at high copper concentration in the Cu-Ni system have been reported and attributed to void formation resulting from high vacancy concentration. 18 In previous investigations, it was shown that the imposition increases the concentration of vacancies in a Cu-Al alloy 23 and decreases the activation energy for defect mobility in a Ti-Ni intermetallic. 9 In view of these observations, the lack of a significant effect by the current on the activation energy at low copper concentrations in this study would suggest that the current effect on mobility is likely to be the cause of the decrease in the activation energy in high concentration samples.…”

“…[16][17][18][19] In Fig. 7͑a͒, we compare our results, calculated from the nickel concentration profiles, with those of Kaja 16 and Schwarz et al 17 at a common temperature of investigation, 650°C.…”

Movement of Multiple Markers in Cu/Zn Multiple Phase Diffusion Couples and Its Numerical Analysis

“…Hear after, we call the markers located at the initial welded interface before diffusion anneal Kirkendall markers and the others multiple-markers (M-Ms). The M-Ms method proposed first by Cornet and Calais [1,2] and developed by Iijima [3] is useful because it enables us to determine the intrinsic diffusion coefficients not only at X k but also at the places where the M-Ms locate. However, their method is not applicable to the alloy system with variable molar volume, V.…”