Evidence for Ag participating the electrochemical migration of 96.5Sn-3Ag-0.5Cu alloy

Ag participating the electrochemical migration (ECM) of Sn-Ag based alloys is still controversial. In this work, Ag+ concentration in electrolyte layer and Ag distribution in dendrites formed during the ECM of 96.5Sn-3Ag-0.5Cu alloy were investigated using Inductively Coupled Plasma Source Mass Spectrometer and Scanning Transmission Electron Microscopy, respectively. Results show that Ag+ can only be detected when Ag can release from Ag3Sn during the anodic polarization of 96.5Sn-3Ag-0.5Cu alloy. Under such a condition, Ag could also be found in dendrites. Therefore, it can be concluded that Ag participates the ECM of 96.5Sn-3Ag-0.5Cu alloy, but it is potential-dependent.