ROLE OF COMPLEX-FORMATION IN CORROSION INHIBITION

Progress in the inhibition of corrosion by organic ligands and complex compounds is considered. It was shown to be possible to retard both general and localized corrosion of different metals by inhibitors of this type. In considering the action of ligands themselves, emphasis is placed on the importance of their chemical structure as expressed through electronic and hydrophobic characteristics. Examples are given for inhibition of corrosion which are difficult to explain solely by competitive adsorption of solution components, but can be understood in terms of nucleophilic substitution of ligands in a surface complex. Attention is drawn to other reactions leading to change in pH of the near-electrode layer, formation of sparingly soluble deposits, and so on. The role of the nature of the complexing agents and its quantitative aspects are discussed with regard to the use of complex compounds of metals as inhibitors.