Synergistic Effects of Metal Cations and Sodium Gluconate on the Inhibition of Freshwater Corrosion of Mild Steel

Abstract

The synergistic effects of metal cations in a solution on the ability of sodium gluconate to inhibit the corrosion of mild steel were investigated by immersion and electrochemical tests. The effects of metal cations on the inhibition ability of sodium gluconate was investigated quantitatively, with particular focus on the parameter Y, which represents the “corrosion inhibitory effect of cations.” The results of the immersion and electrochemical tests showed that the inhibition ability of sodium gluconate improved with increasing Y value of the metal cations in model freshwater. The electrochemical and surface analyses indicated that gluconate ligands and large-Y metal cations formed a protective layer with few defects on the mild steel.

Fig. 11 Corrosion rates of specimens in a solution as a function of the Y value of the metal cation in the solution.