Electrodeposition of Sn-Co-Ni and Sn-Co-Zn alloy coatings on copper substrate in a deep eutectic solvent and their characterization

Abstract

Sn-Co-Ni and Sn-Co-Zn alloy coatings have been electrodeposited on Cu substrate from SnCl2, CoCl2, and NiCl2 or ZnCl2 precursors in choline chloride/urea (ChCl-urea) deep eutectic solvent (DES). Cyclic voltammetry experiments were applied to research the electrodeposition behaviors of Sn-Co, Sn-Co-Ni and Sn-Co-Zn alloy coatings in ChCl-urea ionic liquid. The results reveal that the reduction processes of Sn(II), Co(II), Ni(II) and Zn(II) are all one-step processes. The cathodic potential and electrodeposition time would influence the morphology of the Sn-Co, Sn-Co-Ni and Sn-Co-Zn alloy coatings significantly. With the increase of potential, the morphology of the deposited Sn-Co-Zn alloy coating changed from cubic crystals to flower-shaped particles, while the Sn-Co-Ni alloy coating varied from needle-like crystals to three-dimensional structure. The corrosion resistance of the Sn-Co-Ni and Sn-Co-Zn coatings electrodeposited at different potentials have also been researched and compared. It is suggested that the tin-based ternary alloy coatings with tunable microstructures can be directly and facilely electrodeposited in ChCl-urea electrolyte.