Study of the corrosion inhibitor formamide in the aluminumndash;carbon tetrachloride system using IETS

摘要

Inelastic electron tunneling spectrosocpy (IETS) has been used to determine the molecular species formed on aluminum oxide exposed to formamide. Small concentrations of formamide are known to inhibit the corrosion of aluminum by carbon tetrachloride. IETS spectra were obtained for formamide and its deuteroderivatives and for dilute solutions of formamide in carbon tetrachloride. The spectra show that formamide in the presence of carbon tetrachloride is preferentially adsorbed on the aluminum oxide surface. The results indicate that the formamide surface species are chemisorbed at oxygen vacancy sites which have exposed aluminum atoms. A model is developed to describe the interaction of the formamide molecule with the oxide surface, and show how the formation of an aluminumndash;nitrogen bonded formamide surface species could inhibit the corrosion of aluminum by carbon tetrachloride.