Investigation of the corrosion resistance properties of a new synthesized Schiff base compound on XC48 steel in two acidic media: 1 M HCl and 0.5 M H₂SO₄

• H. Belagra^1,2, F. Benghanem², R. Yekhlef^2,3 and D. Belfennache³

¹ Department of Chemistry, Faculty of Sciences, University Mohamed Boudiaf of M’Sila, University of M’Sila, University Pole, Bordj Bou Arreridj road, M’Sila 28000, Algeria
² Laboratory of Electrochemistry, molecular engineering and Redox Catalysis (LEIMCR), University Sétif-1, Setif 19000, Algeria
³ Research Center in Industrial Technologies CRTI, P.O. Box 64, Cheraga, 16014 Algiers, Algeria

Abstract: Schiff bases represent a crucial group of widely used chemical compounds with various applications across multiple domains. This research investigates the corrosion inhibition properties of a newly developed Schiff base, bis(3-methoxysalicylidene)-4,4ˊ-diiminodiphenyl methane (BMDDM), on XC48 steel in 1 M hydrochloric acid and 0.5 M sulfuric acid using electrochemical methods, specifically potentiodynamic polarization and impedance spectroscopy. The study varied two parameters: concentration (ranging from 10^–6 to 10^–3 M) and temperature (from 30 to 60°C). To understand the mechanism of action of this Schiff base, we calculated and analyzed several thermodynamic parameters related to the activation and adsorption processes (E_a, ∆H_a, ∆G_ads, and ∆S_a). The optimal concentration of 10^–3 M yielded inhibition efficiencies of 89.33% in 1 M hydrochloric acid and 88.37% in 0.5 M sulfuric acid. The findings indicated that the Schiff base acts as a mixed inhibitor, with the inhibition mechanism conforming to the Langmuir isotherm in both acidic environments. The calculated ∆G_ads values suggest that the inhibitor undergoes both chemisorption and physisorption in HCl and H₂SO₄. In terms of temperature effects, the highest inhibition efficiency recorded was 78.45% at 40°C in hydrochloric acid and 76.05% at 30°C in sulfuric acid. Scanning electron microscopy (SEM) images confirmed the formation of organic molecules that create a stable and insoluble protective layer on the surface of XC48 carbon steel.

Keywords: corrosion, Schiff base, inhibitor, XC48 steel, acidic medium

Int. J. Corros. Scale Inhib., 2025, 14, no. 1, 74-96
doi: 10.17675/2305-6894-2025-14-1-5

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