Environmentally friendly electrolyte for the electrodeposition of Cu-Zn alloys

Abstract

Environmentally friendlier and safer alternativesare required as replacement forhighly toxic cyanide baths used by electroplatingindustries. Glutamate has provedto be an adequate complexing agent inalkaline copper and zinc plating baths dueto its capability to form anionic complexeswith those metal ions. Consequently, studieswith a glutamate-based electrolyte for Cu-Zn alloys deposition are presented.In this work, cathodic polarization experiments on a rotating disk electrode in both static and rotatingconditions were carried out using the novel electrolyte with and without the addition of a polymericcationic surfactant (Polyquaternium-7). The deposits were later dissolved by anodic strippingto characterize the electrochemical processes involved in the Cu-Zn-Glutamate system. Galvanostaticexperiments, using flat steel electrodes as substrate, were carried out at different currentdensities with and without additive. These coatings were characterised by SEM, EDS and XRD.Cu-Zn alloys with compositions between 37-83 wt.% of copper were obtained. α, β and γ phaseswere obtained depending on the electrolyte composition and the applied current density.