Electrochemical behavior of Sn-Ni nanostructured compound in alkaline media and the effect of halide ions

Tin-Nickel electrodeposits alloy of the approximate composition 34% Ni-66% Tin (wt.%) can be obtained from the chloride-fluoride bath. The potentiodynamic, cyclic voltammetry, and impedance spectroscopy techniques complemented by XRD and SEM (EDX) were used to study the corrosion behavior of Sn-Ni alloy in sodium carbonate solution (Na2CO3) at pH 11.9. The effect of different factors as concentration of the carbonate ion, the switching potential and the progressive addition of the halide ions on the electrochemical behavior of Sn-Ni alloy is discussed. The observed corrosion resistance of electrodeposited Sn-Ni alloy is due to the formation of a thin passive film, which is examined by X-ray spectroscopy, believed to be mainly nickel and tin oxides. The voltammogram are involving five anodic peaks. The first and second peaks are corresponding to the formation of SnO and SnO2 oxides. The third, fourth, and fifth peaks are related to the formation of nickel oxides. The data is indicating that the corrosion rate and the pitting corrosion of Sn-Ni alloy increases by the addition of the halide ions. (C) 2003 Elsevier B.V. All rights reserved.