Citric Acid as an Alternative to Sulfuric Acid for the Hard-Anodizing of AA6061

Hard-anodized is a widely used method in the aeronautical sector to improve aluminum alloys abrasion and corrosion resistance. Aim of this work was characterize mechanical properties resistance hard-anodized 6061 citric acid solution as replacement sulfuric were investigated. Aluminum alloy base material produce hard anodizing; process carried out solution, applying current densities 3 4.5 A/cm2 subsequently exposed 3.5 wt. % NaCl solution. Microstructure anodizing characterized by scanning electron microscopy (SEM) Vickers microhardness (HV). Corrosion behavior it with electrochemical techniques cyclic potentiodynamic polarization (CPP) impedance spectroscopy (EIS) respectively. Results obtained indicated that all samples anodized showed negative hysteresis lower density (1 × 10?10 A/cm2), indicating generalized on surface. EIS results show A/dm2 provides better protection than