Magnetic field induction effect during Ni film electrodeposition over Cu alloy in watts solution

This study investigates the effect of magnetic field intensity on the electrodeposition behavior and properties of nickel (Ni) coatings deposited on copper (Cu) alloy substrates using a Watts-type electrolyte composed of NiSO 4· 6H 2 O, NiCl · 6H 2 O, and H 3 BO 3 . Electrodeposition was performed at 10 °C and pH 4.2 under a constant current density of 10 mA/cm 2 for 1 hour, with magnetic field intensities of 0 G, 1865 G, and 2405 G. The influence of magnetic field on deposition rate, current efficiency, microstructure, hardness, and corrosion performance was evaluated. The application of the magnetic field reduced the deposition rate and current efficiency due to enhanced hydrogen evolution and modified mass transport at the cathode. XRD analysis confirmed that all coatings consisted of a single face-centered cubic (FCC) Ni phase with dominant (111) orientation. Increasing magnetic field intensity refined the crystallite size and increased lattice strain, indicating a higher defect density. SEM observations revealed a transition from near-spheroidal grains to more faceted morphologies, accompanied by reduced surface roughness. As a result, coating hardness increased significantly which is consistent with grain refinement and the prevalence of the (111) close-packed plane. Electrochemical tests in 3.5 % NaCl solution demonstrated improved corrosion resistance for coatings deposited under higher magnetic fields, with the lowest corrosion rate obtained at 2405 G. Overall, the results show that magnetic field-assisted electrodeposition effectively enhances the corrosion properties of Ni coating, hardness, corrosion resistance through mechanical and microstructural effects, offering promising approach for improving protective coatings on Cu-based components in chloride environments.