Synergistic inhibition effect of l-phenylalanine and rare earth Ce(IV) ion on the corrosion of copper in hydrochloric acid solution

The synergistic inhibition effect of l-phenylalanine (l-Phe) and Ce(SO4)2 on the corrosion of copper in 0.5 M HCl solution was investigated by weight-loss, electrochemical methods and surface analysis. The electrochemical results showed that l-Phe has definite inhibition effects for copper, while Ce(IV) promoted the anodic process of copper corrosion. The combination l-Phe with Ce(IV) ion produced strong synergistic effect on corrosion inhibition for copper. The maximum inhibition efficiency was 82.7% for 5 mM l-Phe + 2 mM Ce(IV). The results of EIS and potentiodynamic polarization are in good agreement. SEM showed that l-Phe and Ce(IV) can form a dense protective film on the copper surface.