A Corrosion Inhibition Study of Some Organic Substances Using DFT Calculations

Abstract

The density functional theory DFT at B3LYP hybrid and 6-311++G basis set have been implemented to investigate the corrosion inhibition of mild steel Fe and copper Cu using some organic compounds that have amid group. The surface energies and electronegativity equations of Pauling and Mullikan were used to calculate the quantum scales factors of inhibition (electronegativity, hardness, softness, and the fraction and energy of charge transfer) of these compounds. For mild steel metal, the results showed that some compounds have high tendency to donate electrons to the metal, Fe since these have low electronegativity scales. Conversely, the others tend to accept electrons and forming the feedback bond of inhibition. But for copper, it is found that all compounds have tendency to accept the charge from the metal since its electronegativity lower than that of inhibitors. Thus it is expected that some compounds have high efficiency of inhibition towards Fe. The other substances have lower inhibition efficiency. But for copper, the corrosion inhibition using these compounds is less efficient.