Inhibitive behaviour of Gum Arabic on corrosion process of pipeline steel in acidic environment

Kazan State Power Engineering University, Krasnoselskaya str. 51, Kazan 420066, Russia

^* Corresponding author: ostefzueva@mail.ru

Abstract

Pipeline steel is highly susceptible to corrosion in acidic environments, requiring the use of inhibitors. Gum Arabic (GA), consisting of branched complex polysaccharide chains, exhibits a good inhibiting effect on the surface of mild steel in various acidic corrosive media. In this paper, the corrosion of API 5L X60 pipeline steel in 1 M HCl solutions and the possibility of its reduction due to the use of GA were experimentally studied. Mass loss, X-ray diffraction, and potentiostatic methods were employed to study the inhibition effect. It was shown that the use of GA as an inhibitor reduces the corrosion rate in units of penetration from 1.17 to 0.226 mm/year, i.e. more than 5 times. The calculated inhibitor efficiency equal to 93% also indicates that GA in concentration 2g/l is a good inhibitor for API 5L X60 pipeline steel in 1 M HCl. The potentiostatic polarization data reveal that the inhibitor affects both cathodic and anodic processes, i.e. it acts in a mixed manner. Optical microscopic examination confirmed the results obtained by X-ray diffraction and showed that the presence of GA increases the resistance of pipeline steel to pitting corrosion.