The Role of Computational Chemistry in Corrosion Inhibition: a Review

Metals and alloys corrosion is one of the most challenging and damaging occurrence that is linked with enormous economic and safety losses, and it becomes more severe during some manufacturing processes by which metallic surfaces are treated for other industrial application processes. The use of corrosion inhibitors is one of the best way to protect metals and alloys against damage. The problem of the environmental toxicity of some of the employed inhibitors and the high cost involved in controlling and preventing corrosion have prompted this review. Computational chemistry methods are mostly significant in reducing the cost of protecting metals and alloys against corrosion. This review article begins with the summary of the most used computational methods, parameters and, finally, summarizes the results of some studies made by different authors in the field of corrosion science and engineering. 5-sulfamethoxazoleazo-3-phenyl-2-thioxo-4-thiazolidinone), as corrosion inhibitors for MS in an acidic medium, using DFT at the B3LYP/6-31G (d, p) and B3LYP/6-311G (d, p) basis set levels. Ab initio calculations using the HF/6-31G (d, p) and HF/6-311G (d, p) methods for quantum chemical parameters/descriptors, namely, E HOMO , E LUMO , ΔE, μ, A, I, X, η,  , polarizability (α), Mulliken charges and fraction of electrons transferred (ΔN) from the inhibitors to Fe, were calculated and correlated with the experimental IE%. Quantitative structure activity relationship (QSAR) approach and a composite index of some quantum chemical parameters/descriptors were also considered to characterize the studied molecules IE. The results showed that the IE% of the studied rhodanine azosulfa drugs was closely related to their theoretical IE%, but with varying degrees of the correlation coefficient (R 2 ). The IE% also increased in E HOMO and decreased in E HOMO -E LUMO , and the areas containing N and S atoms were the most possible sites for bonding to the Fe surface, by donating the lone pair electrons to its empty d-orbital.