A Study on Zinc-Iron Alloy Electrodeposition from a Chloride-Electrolyte

SummaryThe electrodeposition of zinc-iron alloys from a chloride-based electrolyte has been studied using electrochemical polarisation techniques, Ager Electron Spectroscopy (AES), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDXA) and Computer Assisted Pulse Plating (CAPP).A change in the electrodeposition mechanism from equilibrium codeposition to anomalous codeposition with a change in cathodic current density has been observed.Zn-Fe alloys with compositions ranging from less than 5 wt-% to more than 75 wt-% Fe have been electrodeposited from a single electrolyte, making this system ideal for production of compositional modulated alloy (CMA) electrodeposits. Chloride content, pH and agitation of the electrolyte have been observed to have a strong influence on the reaction at the cathode surface, just as the use of pulse reversal current during electrodeposition.A theory on the electrodeposition mechanism, accounting for the above observations, is presented.