Influence of magnesium chloride on the electrodeposition of zinc from the 1,3-dimethyl-2-imidazolidinone/ZnCl2 system

The effect of magnesium chloride (MgCl2) on the electrodeposition of zinc in 1,3-dimethyl-2-imidazolidinone (DMI)/ZnCl2 solvate ionic liquids was investigated. Cyclic voltammetry and Chronoamperometry are employed to study the electrochemical behavior of Zn. The crystal structure, microscopic morphology, and roughness of Zn coatings were measured by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Non-contact Optical Surface Profiler (OSP). The results reveal that adding MgCl2 is favorable to the electrodeposition of Zn and leads to the formation of a new zinc-containing species in the electrolyte, which was confirmed by Raman spectra. Importantly, this addition does not affect the nucleation mechanism of zinc. Furthermore, the zinc grows preferentially on the (101) plane and a more smooth and uniform zinc coating was obtained. Corrosion resistance testing is conducted in a 3.5 wt% NaCl solution using the Tafel method. Coatings obtained at 4 mA/cm2 and 343 K with 0.1 mol/L MgCl2 addition exhibit lower corrosion current density of 38.10 μA/cm2 compared to zinc coatings obtained without MgCl2.