Corrosion Behavior and Mechanism of Pure Al A1060 in Simulated Polluted Marine Atmospheric Environment

The corrosion behavior of pure Al A1060 in 3.5% (mass fraction) NaCl and 3.5 % NaCl + 0.02 mol/L NaHSO₃ solutions which simulated polluted marine atmospheric enrironment was studied by cyclic immersion accelerated corrosion test and electrochemical test. The results show that the pure Al exhibited higher corrosion current density and lower free corrosion potential in polluted marine atmospheric environment, which were 1.01 μA/cm² and -911 mV, respectively. After 720 h periodic immersion corrosion test, the mass loss and corrosion rate of the pure Al in the simulated polluted marine atmosphere were 9.7 g/m² and 0.04 μm/a, respectively. The corrosion rate of the pure Al was 4 times higher than that in the simulated marine atmosphere, and it also faced earlier and more serious pitting corrosion in the polluted marine atmosphere. The in the polluted marine atmosphere induced the protective oxide film on the surface of A1060 pure Al to transform into loose Al₂(SO₄)₃, resulting in the increase of the acidity and conductivity of the thin liquid film, thus promoting the occurrence of corrosion reaction.