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

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)-4,4'-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 degrees 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, triangle H-a, triangle G ad(s) , and triangle 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 triangle 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 degrees C in hydrochloric acid and 76.05% at 30 degrees 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.