Structural properties of the oxide coatings prepared by electrolyte plasma process on the Al 2021 alloy in various nitrogen solutions

AlON–Al2O3 coatings on Al alloy 2021 were prepared in the eco-friendly electrolytes in various nitrogen inducing agents by the electrolytic plasma process (EPP) method. The ceramic coatings formed on 2021 Al alloy was carried out by EPP-treated at room temperature for 15 min. The coatings were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), ball-on-disc friction test and Vickers hardness test. It is found that coatings surface produced in NaNO2, NH4NO3 and NaNO3 additions have a homogeneous morphology of discharge channels. These coatings can protect the Al 2021 alloy substrate from the abrasion well.