Corrosion inhibition of mild steel in 0.5 M HCL by substituted 1,3,4-oxadiazole

Abstract

Organic inhibitors are normally used to inhibit the corrosion of metals or alloys in an aqueous environment. The anti-corrosive property of 5((6-Methyl-2-oxo-2H-chromen-4yl)thiomethyl)-2((N-(3-methyl-quinoxalin-2(1H)one)yl) methyl)-1,3,4-oxadiazole (MOD) on mild steel (MS) was studied. Which acts as a novel corrosion inhibitor for MS in 0.5 M Hydrochloric acid (HCl) solution and corrosion behavior in the temperature range of 303–323 K, without and with the MOD inhibitor, was calculated using potentiodynamic polarization, electrochemical impedance spectroscopy, and weight loss measurements. The surface topography of mild steel with, and without MOD was investigated by Scanning electron microscopy (SEM) technique. The inhibitory efficiency increases with an increase in MOD (50 ppm) concentration and showed a maximum of 84.85% in 0.5 M HCl at 303 K. The variation in kinetic and thermodynamic properties of MOD on MS indicates chemisorption and its mixed kind of inhibition activity followed by the Langmuir adsorption isotherm. The experimental results are supported by Density functional theory (DFT) simulations, indicating a potential corrosion inhibition behaviour of MOD on MS in acidic environments. A suitable mechanism for the corrosion inhibition of mild steel was put forth. The corrosion inhibition mechanism of mild steel was discussed. Mild steel is a low-cost engineering material that can be regularly used for various applications such as construction, advertising, vehicles, furniture, fencing, and more in various conditions, including mild acidic ones with a little caution.