Modulating Micro-Arc Oxidation Coating Properties on 6061 Aluminum Alloy via OH− to F− Ion Ratio Optimization

We investigate the influence of the NaOH to KF ratio in a silicate electrolyte on the corrosion resistance and tribological properties of micro-arc oxidation (MAO) coatings on a 6061 aluminum alloy. By optimizing the electrolyte composition, we achieved significant improvements in coating quality. The surface morphology and composition of the coatings were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Our findings reveal that the coatings produced at a 2:1 NaOH/KF ratio exhibited superior corrosion resistance, with a corrosion potential of −1.279 V, corrosion current density of 1.85 × 10−7 A·cm−2, and protective resistance of 1.50 × 105 Ω·cm2. Additionally, the surface roughness and coating thickness were measured at 0.68 μm and 8.04 μm, respectively, providing a robust foundation for enhancing the anticorrosive and wear-resistant properties of 6061 aluminum alloy.