Corrosion inhibition capacity of two heterocyclic oximes on copper in nitric acid: electrochemical, quantum chemical and surface morphological investigations

摘要

Two heterocyclic oximes (E)-N-hydroxy-1-(pyridin-2-yl)methanimine (Hp2ylm) and (E)-Nhydroxy-1-(pyridin-3-yl)methanimine(Hp3ylm) were synthesized from pyridine-2-carbaldehyde and pyridine-3-carbaldehyde, respectively. These oximes were characterized byvarious spectroscopic tools like UV, IR, MASS and NMR. The inhibition capacity of theseoximes against copper corrosion in 0.1 M HNO3 was determined by polarization andimpedance spectroscopic studies (EIS). At all concentrations, Hp3ylm exhibited higherinhibition efficiency than Hp2ylm. Attempt was made to illustrate the mechanism of corrosioninhibition by these oximes with the help of adsorption isotherm, scanning electron microscopic(SEM) and quantum chemical studies.