Kinetics of the reaction of hydrogen evolution on steel in a hydrochloric acid solution containing corrosion inhibitors

The kinetics of cathodic reduction of hydrogen on low-carbon steel in 2 M HCl (t = 25 °C) containing corrosion inhibitors – catamine AB and IFKhAN-92 – was studied. The main rate constants for the stages of hydrogen gas evolution and the introduction of hydrogen atoms into steel are determined. The additions of catamine AB and IFKhAN-92 inhibited the cathodic reduction of hydrogen and its permeation into steel in an HCl solution. The most effective inhibitor of hydrogen absorption is IFKhAN-92. The inhibitory effect of this compound is due to a decrease in the ratio of the hydrogen concentration in the metal phase to the degree of hydrogen filling of the surface. IFKhAN-92 reduction of hydrogen concentration in the volume of metal determines the preservation of the plastic properties of steels during corrosion in HCl solutions. The high efficiency of IFKhAN-92, as an inhibitor of cathodic reduction of hydrogen and its absorption, is the result of chemisorption of this compound on the surface of the steel and the formation of a polymolecular protective layer.