Preparation of Cu-Sn Alloy Foam by Electrodeposition in Acid Solution

Abstract

Cu-Sn alloy foams were produced by electrodeposition in a 0.5 M sulfuric acid solution using a porous polyurethane (PU) template. A thin seed layer of Ti/Ni was sputter-deposited on the PU template. The sulfuric acid solution contained 10 mM Cu and 1 mMSn to electrodeposit Cu-Sn alloy under diffusion-controlled condition. The effect of the solution temperature on the chemical composition, microstructure, and electrical resistivity of Cu-Sn alloy foams was fundamentally investigated. Increasing the solution temperature has reduced cathodic overpotential for alloy reduction, resulting in improved reduction rate and deposition efficiency of Cu-Sn alloy. Thermal treatment for the removal of the PU template contributed to the microstructural recovery of as-electrodeposited Cu-Sn alloy. Electrical resistivity of Cu-Sn alloy foams was measured using a Ag-wired plastic holder. Their relatively low values, compared to theoretically predicted values, were resulted from the formation of intermetallic compounds within Cu-Sn alloy foam.