Electrochemical Characterization and Corrosion Analysis of Cu-Ni Films Electrodeposited from Different pH Bath

The article discusses the galvanostatic deposition of Cu-Ni films on ITO-coated glass substrate from an aqueous sulphate electrolyte at different pH values. All the films are deposited at a fixed cathodic current of 10 mA by electrodeposition technique. The presence of (111), (200) and (220) X-ray diffraction peaks observed at 2 theta similar to 43 degrees, 50 degrees and 74 degrees indicate that films deposited at different pH values of 1 to 5, have face-centered cubic structure. The increase in crystallite size from 80 to 144 nm, with the variation of pH from 1 to 5 indicates a significant effect of the bath pH on the deposition process. The binding energy peaks at 856 and 861 eV observed in X-ray photoelectron spectroscopy have confirmed the presence of Ni2+ in the hydroxide of nickel (Ni(OH)(2)) and Ni3+ in the oxyhydroxide of nickel (NiOOH), respectively. The binding energy peaks observed at 932.43, 933 and 952.70 eV in XPS are related to Cu(OH)(2), Cu2O, CuO and Cu in all the films deposited at different pH values. The highest corrosion resistance of 52 and 42 k Omega cm(2) obtained by Tafel analysis for the films deposited at pH 3 and 5, respectively, is attributed to the presence of both oxide and hydroxide species.