According to the self-catalytic effect of chloride ion in corrosion process

a new method based on Ag2SO4 as corrosion inhibitor was developed to reduce local corrosion. The corrosion inhibition effect of Ag2SO4 on Alloy690 was studied in 0.005 mol·L-1 NaCl solution by using Tafel polarization curves

electrochemical impedance spectroscopy(EIS) and X-ray photoelectron spectroscopy(XPS). The corrosion current density was greatly decreased. This indicated that (AgCl2)- or (AgCl3)2- between silver ion and chloride ion were formed to decrease activity of chlorine ion in corrosion solution. The adsorption of the complex compound would change the double-layer structure from two layers to three layers

inhibiting the anodic oxidation process of Alloy690. With the increase of concentration of Ag2SO4

equilibrium potential would rise

and capacitance of the solid/liquid interface would decrease. Better inhibition effect than other cases could be achieved when the concentration of silver sulfate and sodium chloride ratio equaled to 0.2. Therefore

silver sulfate is a good corrosion inhibition for Alloy690 in chloride solution.