Effects of temperature on interfacial reactions in γ–InSn4/Ni couples

Abstract

Interfacial reactions in γ–InSn4(Sn–20 at.% In)/Ni couples at 130, 140, 150, and 160 °C were investigated. Ni3Sn4phase with significant indium solubility was formed in the couple reacted at 130 and 140 °C, and the reaction path was γ–InSn4/Ni3Sn4/Ni. For the couples reacted at 150 and 160 °C, even though both γ–InSn4and 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 Ni3Sn4phase 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–InSn4/Ni3Sn4/Ni at the location with Ni3Sn4phase growing on Ni. However, if the Ni3Sn4phase does not nucleate, the liquid phase forms at the interface with accumulation of indium atoms, and the reaction path is γ–InSn4/ liquid/liquid + Ni3Sn4/Ni.