THE ELECTRODEPOSITION AND PROPERTIES OF Zn–Ni + Ni COMPOSITE COATINGS

Interest in Zn–Ni alloys stems from their effective protective properties for steel construction materials. However, the anomalous deposition of these alloys leads to an increased zinc content in Zn–Ni coatings, which can adversely affect corrosion resistance in aggressive environments. This study aimed to enhance the nickel content in Zn–Ni coatings by incorporating nickel powder into the galvanic bath. The research involved depositing electrolytic composite coatings on an austenitic steel substrate, after subjecting the surface to chemical treatments. The deposition current density's influence on the chemical composition, structure, and corrosion resistance of the Zn–Ni + Ni coatings was investigated. The optimal current density for maximum corrosion resistance was found to be between 40-50 mA cm –2, resulting in uniform corrosion processes across the full surface area of the coatings. The use of scanning methods such as the Scanning Kelvin Probe was highlighted for analyzing local changes in corrosion activity. Overall, the findings demonstrate a promising approach to improving the electrochemical properties of Zn–Ni coatings through controlled modification of their composition.