Synergistic effect between glutamic acid and rare earth cerium (III) as corrosion inhibitors on AA5052 aluminum alloy in neutral chloride medium

The synergistic effect of glutamic acid (Glu) and rare earth cerium (III) ion on corrosion inhibition for AA5052 aluminum alloy in 3 wt% NaCl was investigated by electrochemical impedance spectroscopy (EIS), polarization curves and SEM/EDS surface analysis. The results show that the maximum inhibition efficiency reaches 85.4% for 0.05 mM Glu + 0.30 mM Ce3+. The combination of glutamic acid and cerium nitrate produces a strong synergistic effect and forms more complex films to retard the cathodic processes of AA5052 alloy corrosion reaction. Quantum chemistry calculation and molecular dynamics simulation have been taken to analyze the synergistic mechanism. Glu molecules are adsorbed on Al2O3 surface via its polar atoms, and the cerium salt can fill the defects of adsorption film.