Anti-corrosive efficiency of aqueous extract of Cordia dichotoma L. plant leaves as inhibitor for corrosion of carbon steel immersed in hydrochloric acid solution

An aqueous extract from the Cordia dichotoma L. (CDL) plant was examined for its corrosion-inhibiting characteristics using the mass loss technique. Immersed in 1N hydrochloric acid, its corrosion inhibitory effects on carbon steel were the primary focus of the investigation. The highest efficiency of this inhibitor system is 94.60%. This occurs because the active molecules in the extract form a chemical connection with the surface of the metal. The potentiodynamic polarisation method is used to study the inhibitor system, which functions as an anodic inhibitor and regulates the anodic response in direct correlation with its concentration. Studies on electrochemical impedance have shown that the presence of an inhibitor system leads to a drop in double layer capacitance and an increase in surface charge transfer resistance. The surface morphology of the protective layer has been examined using FTIR spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Carbon steel's surface composition was compared to blank, inhibitor, and polished systems using the EDAX technology. For pickling acid, the study's findings are practically relevant. KEY WORDS: Corrosion inhibition, Cordia dichotoma L., Surface morphology, AFM, EIS, Carbon steel, Green inhibitor Bull. Chem. Soc. Ethiop. 2025, 39(10), 1877- 1892. DOI: https://dx.doi.org/10.4314/bcse.v39i10.1