Effect of dissolved oxygen on the electrode reactions of low-carbon steel in 1 M HCl containing butyndiol and propargyl alcohol

• Ya.G. Avdeev¹ and K.L. Anfilov²

¹ A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31, 119071 Moscow, Russian Federation
² Bauman Moscow State Technical University (Kaluga Branch), Bazhenov str. 2, 248000 Kaluga, Russian Federation

Abstract: The corrosion of St3 low-carbon steel in 1 M HCl (25°C) solution containing dissolved molecular oxygen with inhibition by acetylenic alcohols, butyndiol and propargyl alcohol was studied by the voltammetric method using a disk electrode rotating at various velocities (0, 460, 780, 1090, and 1400 rpm). The corrosion of steel in the media under study is driven by three partial reactions: anodic ionization of iron and cathodic reduction of protons and molecular oxygen. The first two reactions occur in kinetic mode, while the latter reaction occurs in diffusion mode. An increase in the content of molecular oxygen in the acid solution, both in the presence and the absence of the inhibitors under study, accelerates steel corrosion due to acceleration of the cathodic reaction on the metal by oxygen. It is noted that dissolved oxygen reduces the efficiency of steel protection in HCl solutions by the corrosion inhibitors under study because they weakly hinder the cathodic reduction which occurs in diffusion mode. Competitive adsorption of acetylenic alcohols and molecular oxygen on steel from 1 M HCl is observed, which is also a reason for the poorer efficiency of the inhibitors under study in the protection of steel.

Keywords: acid corrosion, corrosion inhibitors, propargyl alcohol, butyndiol, acetylenic alcohols, mild steel, diffusion kinetics, oxygen reduction

Int. J. Corros. Scale Inhib., 2023, 12, no. 1, 84-100
doi: 10.17675/2305-6894-2023-12-1-5

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