Electrodeposition of Copper and Brass Coatings with Olive-like Structure

Abstract

One method of creating a brass coating is through electrodeposition, which is most often completed in cyanide galvanic baths. Because of the toxicity of cyanides, many are working on the development of cyanide-free baths, which are promising but not satisfactory to replace the classic methods. The purpose of the study was to explore a new generation of non-aqueous cyanide-free baths based on 1-ethyl-3-methylimidazolium acetate ionic liquids. The study involved the formation of copper, zinc, and brass coatings. The influence of the bath composition, cathodic current density, and temperature was determined. The obtained coatings were characterized by their morphology, chemical composition, roughness, and corrosion resistance. It was found that the structure of the obtained coatings is strongly dependent on the process parameters. The three main structures observed were fine-grained, porous, and olive-like. To the best knowledge of the authors, it is the first time the olive-like structure was observed in the case of an electrodeposited coating. The Cu-Zn coatings consisted of 19–96 at.% copper and exhibited relatively strong corrosion resistance. High improvement of corrosion properties was found in the case of copper and brass coatings with an olive-like structure.