Synthesis, characterization and anticorrosion behaviour of a novel hydrazide derivative on mild steel in hydrochloric acid medium

A novel corrosion inhibitor, namely $$N'$$ -[(4-methyl-1H-imidazole-5-yl)methylidene]-2-(naphthalen-2-yloxy) acetohydrazide (IMNH), has been synthesized and characterized by $$¹$$ H NMR and FTIR spectroscopic techniques. The anticorrosion behaviour of IMNH on mild steel in 1 M hydrochloric acid (HCl) medium was studied by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques. The percentage inhibition efficiency of IMNH increased with increase in its concentration and temperature. The adsorption of IMNH followed chemisorption and obeyed Langmuir’s adsorption isotherm. PDP study revealed that IMNH functioned as a mixed type inhibitor. Theoretical study of the adsorption behaviour of this inhibitor was carried out by quantum chemical calculations using density functional theory (DFT). Scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy-dispersive X-ray spectroscopy (EDX) studies confirmed the formation of a protective film of IMNH on the mild steel surface.