Influence of additive on nanocrystalline, bright Zn-Fe alloy electrodeposition and its properties

The nanocrystalline, bright Zn-Fe alloy electrodeposit was prepared by using additive, condensation product of veratraldehyde and valine (VV). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis in the presence of an additive showed nanocrystalline nature of deposit. These studies also revealed the change in surface morphology, phase composition and orientation of coating. The additive, increases faradaic efficiency and throwing power of plating bath. In addition, appearance, hardness, adherence, ductility and corrosion resistance of Zn-Fe alloy deposit are also improved in the presence of the additive. Simultaneously, at different current densities both faradaic efficiency and throwing power increase to peak values, 91% and 23%, respectively, and thereafter decrease. The iron content and hardness of the bright coating change with applied current density. The lower corrosion resistance of bright Zn-Fe deposit at higher current density was reflected by more negative corrosion potential and lower impedance. (C) 2013 Elsevier B.V. All rights reserved.