The role of acid-base interactions in metal corrosion. Review

This review presents an electrode-kinetic model of the origin of aluminum pitting corrosion, taking into account the charge of the metal surface, the adsorption of chloride ions on the oxide surface, their penetration through the oxide film using oxygen vacancies and the initiation of pitting corrosion at the metal/oxide interface. It is shown that the critical potential of pitting formation is a function of the potential of a thin layer of a metal (aluminum) surface coated with an oxide, and the value of the pitting potential of binary surface alloying is related to the isoelectric point of the oxide of the alloying element in the binary alloy. An electrode-kinetic model of the occurrence of pitting is described, which is used to explain the effect of surface alloying on the occurrence of pitting in binary alloys. A method for changing the surface charge is proposed, including the formation of foreign surface organosilicon nanolayers carrying both negatively and positively charged groups. It is shown that four characteristics (charge ( q ), surface potential (Ψ1), critical pitting potential ( E pit ) and metal's tendency to depassivation) depend on the nature of ion-exchange groups, the degree of their acid dissociation and ion-chemical interaction with activator ions.