Interfacial reaction between Sn–Ag alloys and Ni substrate

Interfacial reactions between different compositional Sn–Ag alloys and Ni substrate at 493 K for different durations were investigated. Only one intermetallic compound (IMC), Ni3Sn4, was detected at the interface. This result was attributed to combining effects of driving force for the IMC formation and diffusion of Ni across the interface. Furthermore, it was found that the growth of Ni3Sn4 layer at the interface with annealing time obeys a parabolic rule, which implies a diffusion-controlled mechanism. In addition, the thickness of Ni3Sn4 layer decreases with increasing Ag content in the Sn–Ag alloys.