Electric current effects on Sn/Ag interfacial reactions

The effect of electric current on the Sn/Ag interfacial reaction was studied at 140°C and 200°C, by examining the growth of phase (ε-Ag₃Sn) in the Sn/Ag reaction couples with a constant current density. Only at 140°C was the growth of phase affected by the passage of electric current. The growth rate was enhanced when diffusion of Sn and electron flow were in the same direction, and retarded when they were in the opposite direction. It was found that the diffusion coefficient of Sn through Ag₃Sn was 3.37 μm²/h and the apparent effective charge for Sn in Ag₃Sn was −90, at 140°C.