Gamma-phase Zn-Ni Alloy Deposition by Pulse-electroplating from a Modified Deep Eutectic Solution

This article describes the electroplating of Znsingle bondNi alloy from a modified deep eutectic solvent (DES), a mixture of choline chloride (ChCl) and ethylene glycol (EG) commonly known by its commercial name Ethaline. In this study the Ethaline was modified with propylene carbonate (PC) to decrease the solution viscosity. Boric acid was also used as an additive to improve surface finish and adhesion. The modifications were shown to increase the reduction rate of metal ions through improved mass transport and also to improve the quality of finish (morphology and interfacial adhesion) of the coating. We demonstrate that it is possible to produce dense, thick and adherent coatings of a γ-phase Znsingle bondNi alloy with 81–85% Zn on mild steel substrates using either potentiostatic deposition or controlled current pulse-plating techniques. Mild steel is a typical substrate for a sacrificial anti-corrosion coating used in many applications where the alloy serves to protect the steel from corrosion in harsh environments.