Relative contributions of Ni2+ and Zn2+ reduction currents to anomalous electrodeposition of Zn-Ni alloys

We report our finding that the linear sweep voltammetric (LSV) currents obtained during the electrodeposition of the ZnNi alloy from solutions containing no or organic additives under convective conditions can be described by simple linear combinations of their component currents, i.e., the Ni2+ and Zn2+ reduction currents. The fitting of a given LSV current for codeposition of nickel and zinc requires a given fractional contribution of the Ni2+ reduction to the overall process as well as a coefficient of how efficient the overall process is. The chemical compositions calculated from the coefficients used for fitting linear combinations are in excellent agreement with those actually measured with just one exception. The coefficients thus obtained are expected to be useful in predicting and explaining the anomalous behavior of the alloy electrodeposition. (C) 2004 The Electrochemical Society.