The formation of intermetallic compounds in bimetallic couples was studied, at ambient to 183C, by measuring changes in the contact resistance and composite electrical resistance as a function of time and temperature. It was found that, in the case of bulk diffusion, Cu diffused rapidly into Sn at room temperature and formed eta-prime Cu6Sn5. Further diffusion through this phase was governed by an activation energy of 0.4eV; assuming the occurrence of defect-assisted diffusion into the grains. It was found that grain boundary diffusion was governed by an activation energy of 0.78eV (tables 93 and 94). The use of scanning electron microscopy confirmed the occurrence of grain boundary diffusion of Sn in Cu.

A.K.Bandyopadhyay, S.K.Sen: Journal of Applied Physics, 1990, 67[8], 3681-8

Figure 18

Radiation-Enhanced Diffusivity of Ni (a) and Pd (b) in Cu3Au