A detailed investigation on the corrosion inhibition effect of by newly synthesized pyran derivative on mild steel in 1.0 M HCl: Experimental, surface morphological (SEM-EDS, DRX& AFM) and computational analysis (DFT & MD simulation)

The present paper examines the adsorption of two novel heterocyclic compounds of the pyran derivatives, namely, 2-amino-4-(2-chlorophenyl)-5-oxo-4,5-dihydropyrano [3 ,2-c]chromene-3-carbonitrile (PY-2Cl) and 2-amino-4-(4-chlorophenyl)-5-oxo-4,5-dihydropyrano[3,2c]chromene-3-carbonitrile (PY-4Cl) against the corrosion of mild steel (MS) in molar hydrochloric acid (HCl) medium. The experimental investigation was carried out utilizing a series of techniques including Weight Loss (WL), Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Polarization (PDP). Results showed that inhibition effectiveness of PY-2Cl and PY-4Cl increases with their concentration. Polarization results showed that PY-2Cl and PY-4Cl displayed mixed type behaviour. Inhibition efficiencies of PY-2Cl and PY-4Cl followed the order: 85.8% (PY-4Cl) < 91.2% (PY-2Cl).The adsorption process of PY-2Cl and PY-4Clonto MS surface follows Langmuir adsorption model. Surface characterization analysis utilizing Scanning Electron Microscopy (SEM) coupled with Energy dispersive X-ray analysis (EDS), Atomic Force Microscopy (AFM)and Infrared Spectroscopy (FT-IR) supported the existence of a barrier layer covering the MS. WL measurements were also tested utilizing inductively coupled spectroscopy (ICP) and UV-vis spectrometry (UV-vis). (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the corrosion inhibition of two novel pyran derivatives on mild steel in hydrochloric acid medium. Experimental results showed that the inhibition effectiveness of these compounds increased with concentration and followed the Langmuir adsorption model. Surface characterization analysis supported the presence of a barrier layer on the mild steel surface due to the adsorption of the compounds.