Corrosion Inhibition Mechanisms of Inhibitors in Acid Solutions Considered Based on the Hard and Soft Acids and Bases Principle

Abstract

Inhibition mechanisms of adsorption and precipitation inhibitors for metallic corrosion in acid solutions were discussed based on the hard and soft acids and bases principle. A markedly high inhibition efficiency of decamethyleneimine（CH₂）₁₀ NH was explained by the formation of a stable chemisorption bond between Fe surface（soft acid） and N atom of the imine（soft base） caused by strain in the ring. Inhibition of cationic electrostatic adsorption inhibitors, back-donation inhibitors, dibenzylsulfoxide, propargyl alcohol, bismuth ion and benzylthiocyanate were also discussed on the basis of the principle.