Copper-nickel alloy coating on mild steel from electrolytic bath using co-electrodeposition for improved corrosion resistance

The most prevalent metal used in industry is mild steel (MS). On the other hand, MS corrodes quickly in the environment. A potential strategy to prevent corrosion of MS is to apply a protective coating using more noble metals, such as copper or its alloys. In the present work, Cu–Ni alloys were successfully coated on a MS substrate using an electrodeposition approach with sulphate bath that contained precursors of Cu and Ni ions. The surface structure of the coatings was investigated using Field emission scanning electron microscopy (FESEM). Energy dispersive x-ray spectroscopy (EDS) was used to validate the elemental composition of the coatings. The phase structure of the alloy coating was investigated using X-ray diffraction (XRD) studies. The direct contact plate count method, was used to examine the antimicrobial properties of Cu–Ni alloy coating. The formation of a Cu phase in the Cu–Ni alloy coating resulted in excellent antimicrobial activity against Escherichia coli and Candida albicans . It is anticipated that MS coated with Cu–Ni alloy, exhibits better antimicrobial activity and corrosion resistance, which offers a long-lasting antimicrobial function for use in biomedical devices. Potentiodynamic polarization and electrochemical impedance techniques were used to study the corrosion behaviour of Cu–Ni alloy coating, in 3.5 wt% NaCl solution and the electrochemical behaviour of the coating in acidic sulphate solution. The result shows that the Cu–Ni coating had the highest corrosion resistance (6.5 × 10 −2 mm/y) at 3.00 A/dm 2 . Therefore, this alloy coating will find usefulness in applications for medical instruments and automobiles. • A new, low cost, Cu–Ni alloy coatings were developed by electroplating technique using sulphamic acid as an additive. • The Cu–Ni alloy deposit at 3A/dm 2 shows maximum corrosion resistance. • Better corrosion resistance of Cu–Ni alloy deposit at optimized CD (3 A/dm 2 ) in 3.5% NaCl solution. • The effects of chemical composition and topographic structures of Cu–Ni alloy coating were investigated.