Effect of Quaternary Ammonium Salts and 1,2,4-Triazole Derivatives on Hydrogen Absorption by Mild Steel in Hydrochloric Acid Solution

Abstract

The treatment of low-carbon steel items with hydrochloric acid solutions is used in many industrial technologies. This process is accompanied not only by metal corrosion losses, but also by hydrogen absorption by the metal. In this study, the kinetics of hydrogen cathodic reduction on low-carbon steel in 2 M HCl containing corrosion inhibitors, namely, quaternary ammonium salts and a 3-substituted 1,2,4-triazole, have been studied. Adsorption isotherms of corrosion inhibitors on cathodically polarized steel surface have been obtained. XPS data provide valuable information on the composition and structure of protective layers formed on steel in HCl solutions containing inhibitors. The main rate constants of the stages of gaseous hydrogen evolution and incorporation of hydrogen atoms into the metal have been determined. The addition of quaternary ammonium salts or 3-substituted 1,2,4-triazole inhibits the cathodic reduction of hydrogen and its penetration into steel in the HCl solution. 3-substituted 1,2,4-triazole is the most efficient inhibitor of hydrogen absorption. The inhibitory effect of this compound is caused by a decrease in the ratio of the hydrogen concentration in the metal phase to the degree of surface coverage with hydrogen. The maximum decrease in hydrogen concentration in the metal bulk in the presence of the 3-substituted 1,2,4-triazole is 8.2-fold, which determines the preservation of the plastic properties of steel as it corrodes in HCl solutions. The high efficiency of the 3-substituted 1,2,4-triazole as an inhibitor of hydrogen cathodic reduction and absorption results from strong (chemical) adsorption of this compound on the steel surface and the formation of a polymolecular protective layer.

Thin 1,2,4-Triazole Films for the Inhibition of Carbon Steel Corrosion in Sulfuric Acid Solution

“…To facilitate the hydrogen ionization process, a layer of palladium was deposited onto the diffusion side of the membrane (Figure 1). The procedures of membrane preparation and performing the experiment were reported elsewhere [28].…”

“…The basics of IPZ [40] analysis for calculating the rate constants of the main stages of cathodic evolution and hydrogen absorption by a metal in an acid solution containing an organic inhibitor are given in [28]. Therefore, we will only give the equations required for the calculation of these constants along with their brief description.…”

“…Upon contact with acid solutions, steel items not only undergo general corrosion but also lose mechanical ductility due to hydrogen absorption by the metal. The ductility of steel is often affected by hydrogen embedded in the metal bulk [23][24][25][26][27][28].…”

“…The choice of this compound is due to its potential ability to form thin protective films characteristic of triazoles on metals. Earlier [28], we conducted a study of the action of 3ST on the corrosion and strength properties of steels in aggressive environment. It was found that the maximum effect was observed in the presence of 5 mM inhibitor in the solution.…”

Effect of Cathodic Protection Potential Fluctuations on the Corrosion of Low-Carbon Steels and Hydrogen Absorption by the Metal in Chloride Solutions with Nearly Neutral pH

“…The membrane was 3.5 cm in diameter and 0.1 mm thick, and the surface area in contact with the electrolyte was 3 cm 2 . A palladium layer was applied on the diffusion side of the membrane, as described in [ 31 ]. The diffusing part of the cell was filled with 0.1 M NaOH, and the membrane was polarized at a potential of 0.45 V (SHE).…”