Effects of Sulfide Ions on the Inhibiting Efficiency of EDA as a Copper Corrosion Inhibitor in Dilute HCl Solution

The anticorrosion action of EDA on copper in dilute HCl solution and the effect of sulfide ions on the inhibiting efficiency were studied by the Tafel plot method.The corrosion potential of Cu shifted to more positive value and the corrosion current density decreased after the addition of Na_(2)S to the solution.The results indicated that sulphide ions could increase the inhibiting efficiency of EDA because of the synergistic inhibition effect between EDA and Na_2S,resulting from the adsorption of HS~(-)on the surface of Cu,facilitated the adsorption of EDA to form a highly protective adsorbed layer which prevented Cu from corrosion.