Effect of organic corrosion inhibitors on the kinetics of the cathodic hydrogen evolution reaction on steel in a sulfuric acid solution

Abstract

The kinetics of hydrogen cathodic reduction on low-carbon steel in a sulfuric acid solution containing a mixture of quaternary ammonium salts (catamine AB) and 3-substituted 1,2,4-triazole (IFKhAN-92 inhibitor) has been studied. The main rate constants of the stages of evolution of gaseous hydrogen and the permetion of hydrogen atoms into the metal are determined. It is shown that these substances reduce the reaction rate of the discharge of H+ ions, change the ratio between the concentrations of H atoms on the surface and in the phase of the metal, and, as a result, reduce the amount of hydrogen absorbed by steel. The most effective inhibitor of corrosion and hydrogenation of steel is IFKhAN-92, due to the formation of a polymolecular protective layer of the inhibitor on the metal surface. The data of X-ray photoelectron spectroscopy of the steel surface show that the protective layer has a thickness of no more than 4 nm and consists of IFKhAN-92 molecules associated with the steel surface by chemical interaction, and inside the layer by physical interaction.