Preparation and characterization of jet electrodeposited Ni-W-Al2O3 coatings

This study investigates the influence of fluid flow rates (V_i) on the performance of Ni-W-Al₂O₃ coatings. The coatings were deposited via jet electrodeposition with varying V_i to assess their impact on coating properties. Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), microhardness testing, and wear resistance evaluations were employed to characterize the microstructure, composition, hardness, and wear resistance of the coatings. The results showed that the coating deposited at 1.0 m/s exhibited a uniform, compact, and fine microstructure. The thicknesses of the three coatings were 28.1 μm, 46.5 μm, and 37.4 μm, respectively. The sample deposited at 1.0 m/s displayed the lowest intensity of the Ni-W diffraction peak. XPS analysis revealed a complex chemical composition, including both metallic and oxidized forms of nickel, tungsten, and aluminum, along with various oxygen species. At 1.0 m/s, the Ni-W-Al₂O₃ coating achieved a microhardness of 725.4 HV, the highest among the four coatings and approximately 61.4 % greater than that of the Ni-W coating. The friction coefficient and wear loss for this sample were 0.46 and 15.7 mg, respectively. It exhibited the smallest wear scar, approximately 13.5 μm and about one-fifth that of Q235 steel demonstrating excellent wear resistance. Electrochemical testing further confirmed that the coating deposited at 1.0 m/s exhibited the highest corrosion resistance, characterized by the most positive corrosion potential (−0.104 V), the lowest corrosion current density (7.582 × 10⁻⁷ A cm⁻²), and the highest polarization resistance (8167.0 Ω cm²), indicating improved protective performance in corrosive environments.