Effect of Passivation Time on the Corrosion Resistance of 6005A Aluminum Alloy

To enhance the corrosion resistance of 6005A aluminum alloy in chloride-containing environments, chemical passivation was conducted in a 1 mol/L sulfuric acid solution for varying durations. The influence of passivation time on the corrosion behavior was systematically investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Experimental results revealed that passivation time significantly affects the compactness and stability of the passive film, exhibiting a trend of initial improvement followed by deterioration in corrosion resistance. When the passivation time was 70 min, the alloy exhibited the most positive corrosion potential and pitting potential, the lowest corrosion current density, and the highest impedance modulus and phase angle peak, indicating the formation of an optimally structured passive film with superior protective performance. These findings provide both theoretical and experimental guidance for optimizing the passivation process parameters of 6005A aluminum alloy.