Synthesis and application of new acetohydrazide derivatives as a corrosion inhibition of mild steel in acidic medium: Insight from electrochemical and theoretical studies

Corrosion inhibition of mild steel in 15% HCl solutions by synthesized acetohydrazides namely, N′-[(1Z)-phenylmethylene]-2-(quinolin-8-yloxy) acetohydrazide (PQA) and N′-[(1Z)-4-chlorophenylmethylene]-2-(quinolin-8-yloxy) acetohydrazide (CPQA) was studied using chemical (weight loss) and electrochemical (potentiodynamic and electrochemical impedance spectroscopy) measurements. It was shown that PQA and CPQA act as good corrosion inhibitor for mild steel protection. It was concluded that the inhibition efficiencies increased with increase in the concentrations of the inhibitor. Tafel polarization studies showed that both the studied inhibitors act as mixed type inhibitor. The high inhibition efficiencies were attributed to the simple blocking effect by adsorption of inhibitor molecules on the steel surface. Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM) and Energy Dispersion X-ray Spectroscopy (EDX) observations confirmed the existence of an absorbed protective film on the metal surface. The density functional theory (DFT) was employed for theoretical calculations and the obtained results were found to be consistent with the experimental findings.