Study on electrodeposition and corrosion resistance of Cu-Sn alloy prepared in ChCl-EG deep eutectic solvent

The paper presents several experimental results regarding the electrodeposition of Cu-Sn alloy coatings prepared in ChCl-EG deep eutectic solvents (DESs). The electrochemical behavior of Cu2+ and Sn2+ on glassy carbon electrode (GC) was studied by cyclic voltammetry (CV). The nucleation mechanism of Cu2+ and Sn2+ at different potentials was analyzed by the potentiostatic current density transient (chronoamperometry (CA)). Surface and phase composition of Cu-Sn alloy coating were characterized by scanning electron microscopy (SEM/DEX) and X-ray diffraction (XRD). The corrosion resistance of Cu-Sn coating was studied by potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS). From the results, it can be seen that the Cu-Sn alloy can be co-deposited at the potential from − 0.5 to − 0.8 V. The surface of the coating showed a different microstructure when the deposition potential changed. With the negative shift of deposition potential (− 0.5 to − 0.8 V), the particle size of the coating decreased. Comparison in the corrosion behavior of the coatings showed that the change of Sn content had an effect on the corrosion resistance of Cu-Sn alloy. The thickness of the coating (from 7 to 11 μm) was obtained by electrodeposition at − 0.8 V (1 h).