Synergistic corrosion inhibition of mild steel by chalcone derivatives and KI in acidic media via computational and experimental methods

The corrosion inhibition characteristics of chalcone 4-hydroxy-6-methyl-3-(3-phenylacryloyl)-2H-pyran-2-one derivatives with different functional groups (H, Cl, -CH₃, -NO₂, -OCH₃) studied employing density functional theory (DFT). The study identified the CH-OCH3 derivative as the most effective inhibitor among the compounds analysed. This derivative was synthesized and characterized through IR, ¹H NMR and ¹³C NMR spectroscopy. The CH-OCH₃ inhibitor then studied for its mild steel corrosion inhibition capability using Electrochemical and surface analysis in 1 M HCl. CH-OCH₃ inhibitory efficacy rises in proportionately with their concentration, according to electrochemical results and reaches 85.4 % at 10⁻³ M. Potentiodynamic polarization revealed that it operates as mixed-kind of inhibiting nature. CH-OCH₃ adheres to the Langmuir isotherm when they bind over the mild steel surface. The deposition of the inhibitors on metal surface is additionally verified by surface study utilizing AFM. Additionally, the influence of KI addition over CH-OCH₃ inhibition property has been studied.