Preparation and characterization of Ni–AlN nanocoatings deposited by magnetic field assisted electrodeposition technique

Abstract In this study, traditional nickel coating and Ni–AlN nanocoatings were deposited on mild steel surfaces using magnetic field-assisted electrodeposition (MFAED) technique. Microstructures, compositions, and microhardness values of nanocoatings were examined by digital holographic microscopy (DHM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The microhardness, wear, and corrosion properties of nanocoatings were also examined. The nanocoating prepared at 0.4 T (abbreviated as S-0.4) showed uniform and compact structure with AlN and Ni sizes around 42.7 nm and 84.2 nm, respectively. Diffraction peaks of nickel grains became broader and lower in intensity as magnetic field rose from 0.2 T to 0.4 T, indicating nickel grains refinement in S-0.4 nanocoating. Among three coatings, S-0.4 nanocoating exhibited the highest microhardness with average value of 846.2 Hv and lowest mass loss of 46.4 mg. By comparison, S-0 coating exhibited the highest mass loss with average value of 95.7 mg. S-0.4 nanocoating exhibited the minimum corrosion current density of 0.35 × 10−4 A/cm2, demonstrating the best corrosion resistance among all three coatings.