Optimization of Zn-Ni Alloy coating to enhance corrosion resistance of carbon steel

Zn-Ni alloys have gained considerable attention due to their superior ability to resist corrosion. Zn-Ni electroplating can be improved by optimizing the nickel composition in Zn-Ni alloys, which provides better protection compared to Zinc deposited alone; it can also be improved by incorporating additives into the plating bath. The aim of our research was to optimize our electroplating bath by adding an eco-friendly additive to enhance the characteristics of the deposits obtained, particularly their morphology after electrodeposition, and their resistance against corrosion, using different concentrations of this additive (0g/l, 0.25g/l, 0.5 g/l, 1g/l and 2g/l). Several deposits were made for this purpose and their properties were investigated. We used scanning electron microscopy (SEM) to examine the deposits' surface morphology, while energy-dispersive spectroscopy (EDS) was used to assess the chemical composition of the deposits. Electrochemical methods, polarization measurement (PDP) and electrochemical impedance spectroscopy (EIS), were used to investigate the corrosion resistance of every deposition in an ASTM D1384-87 medium. The results show that the incorporation of the eco-friendly additive into the electroplating bath significantly improves both the morphology and corrosion resistance of Zn-Ni coatings. Compared to all the deposits produced in this study, the optimum concentration is 1g/l of the additive, which produced the most corrosion-resistant Zn-Ni alloy deposit.