Surface analysis methods in the investigation of corrosion inhibitor performance

Summary Being economical and easily applied, organic corrosion inhibitors are finding increasing use. The efficacy of inhibitors is normally investigated by gravimetric and electrochemical methods. For further information — for example, on the thickness, composition and structure of protective films, or the binding states of the inhibitor and metal — surface analysis methods, such as ESCA, AES, SIMS and LAMMA, must be used. The system copper/ benzotriazole or tolyltriazole in tap water is investigated as an example of interface inhibition. A quasipolymeric film with a thickness of only a few molecular layers is formed from Cu(I) and inhibitor and is remarkably resistant even to air and solvents. Phosphonic acids act as membrane inhibitors on iron in cooling water. Together with corrosion products and ions from the water they form layers with a thickness of about 20–40 nm. As their growth then ceases, they cause no hindrance to heat transfer.

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Oberflächenanalytische Methoden zur Untersuchung der Wirksamkeit von Korrosionsinhibitoren