Electrodeposition, structural, and corrosion properties of Cu films from a stable deep eutectics system with additive of ethylene diamine

A comparative study was carried out on the deposition mechanism, microstructure, and corrosion resistance of Cu films electrodeposited from the base electrolyte of CuCl2·2H2O in a choline chloride–ethylene glycol eutectic solvent with absence and presence of the additive of ethylene diamine (EDA). The base electrolyte is unstable and produces rough Cu films with columnar grains. Upon the introduction of EDA, the modified electrolyte becomes stable and the nucleation of Cu deposits is strongly inhibited, thus producing a smooth and compact surface with finer grains. Uniform corrosion and decreased corrosion current density are recognized in the fine grained Cu films.