Abstract
Interfacial reactions in γ-InSn 4 (Sn-20 at.% In)/Ni couples at 130, 140, 150, and 160 °C were investigated. Ni 3 Sn 4 phase with significant indium solubility was formed in the couple reacted at 130 and 140 °C, and the reaction path was γ-InSn 4 /Ni 3 Sn 4 /Ni. For the couples reacted at 150 and 160 °C, even though both γ-InSn 4 and Ni were solid phases, the liquid phase was formed in the couples. A distinguished feature was the nickel substrates becoming nonplanar with spikes at various locations and the Ni 3 Sn 4 phase layer on top of the nickel spikes. Except at regions near the nickel spikes, the reaction layer consisted of precipitates and was not a homogeneous phase. The reaction path is γ-InSn 4 /Ni 3 Sn 4 /Ni at the location with Ni 3 Sn 4 phase growing on Ni. However, if the Ni 3 Sn 4 phase does not nucleate, the liquid phase forms at the interface with accumulation of indium atoms, and the reaction path is γ-InSn 4 /liquid/liquid + Ni 3 Sn 4 /Ni. © 2006 Materials Research Society.