Electrochemical Behavior of Sn-Ag Alloys in Alkaline Solutions

Abstract

Abstract The behavior of four Sn-Ag alloys and their individual metal components in sodium hydroxide (NaOH) solutions was studied using open-circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The results reveal that each of the initial open-circuit potential at zero time, Ei, and final open-circuit potential after 60 min, Ef, (at concentrations <0.30 M) shifts toward more negative values, indicating a relatively higher rate of dissolution during the spontaneous oxide growth/oxide dissolution process under the currentless conditions. While at concentrations <0.30 M, there is no significant change in potential. The two corrosion parameters (corrosion potential [Ecorr] and corrosion current density [icorr]) show a linear relation with both the solution concentration and alloy composition. EIS results show that each of the total resistance (RT) and reciprocal capacitance (C−1) values decreases with an increase in the tin content up to 50%. After that, there is l...