Corrosion inhibition of 8-HQ for AA5052 in 3 wt% NaCl solution in presence of trace Cu2+ ions: Electrochemical/surface studies, DFT/MD modeling

Abstract

In this paper, the effect of Cu2+ ions on corrosion inhibition of 8-hydroxyquinoline (8-HQ) for AA5052 aluminum alloy in the simulated seawater solution has been studied by weight loss experiments, electrochemical measurements and surface analysis. 8-HQ inhibits the corrosion of AA5052 aluminum alloy in 3 wt% NaCl solutions very well, resulting in a positive shift in corrosion potential. The 0.01 mg/L of Cu2+ ions can deteriorate the corrosion inhibition of 8-HQ at low concentrations. This behavior is interpreted on the basis of deposition of copper by displacement on the defects of the corrosion inhibition film of 8-HQ. When the concentration of 8-HQ reached 5 mg/L, the presence of 0.01 mg/L Cu2+ ions increase the corrosion inhibition efficiency of 8-HQ by 6.27%. 8-HQ shows efficient inhibition at a relative high concentration, suggesting that the chelate formed by Cu2+ ions and 8-HQ can repair the defects of the 8-HQ inhibitive film on aluminum surface. The complex film would suppress the partial cathodic reaction and lead to the improved corrosion inhibition.