Corrosion screening of chamber inhibitors for an aluminum alloy

• O.A. Goncharova, D.S. Kuznetsov, N.N. Andreev, Yu.I. Kuznetsov, N.P. Andreeva and S.S. Vesely

A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31, 119071 Moscow, Russian Federation

Abstract: The chamber method is a version of vapor-phase protection of metals from atmospheric corrosion. In this method, thin adsorption films with long-term protective after-effect are formed on the articles by short-term metal treatment with vapors of low-volatile compounds at elevated temperatures. It is rather a new method. Its theoretical bases have been little developed so far and a search for efficient chamber corrosion inhibitors still remains an empirical process. In this study, a combination of physical (ellipsometry, wetting angle measurements), electrochemical (potentiodynamic anodic polarization, electrochemical impedance spectroscopy) and corrosion methods (tests under recurrent moisture condensation conditions) was used to study the properties of adsorption films formed on aluminum alloy AMg6 by the “chamber” method in vapors of amines (octadecylamine, triethanolamine, tribenzylamine and diaminopropane), heterocyclic compounds (Captax, Altax and 3-amino¬triazole), carboxylic acids (stearic, oleic, benzoic, succinic, crotonic, neodecanoic, isophthalic, isonicotinic, linolenic, flufenamic, ascorbic acids and carboxylic acid A), as well as salts of carboxylic acid A (with dimethylaminoethanol, urotropine and dimethylbenzylamine). It has been found that chamber treatment of the alloy with the compounds listed above improve its corrosion resistance in a humid atmosphere, though not efficiently enough. The carboxylic acids themselves are most promising agents, and the optimum temperature of surface treatment by these compounds is 140°C. One-hour treatment of steel with vapors of oleic or neodecanoic acids or carboxylic acid A at this temperature creates nano-sized adsorption films on AMg6 alloy. They slightly hydrophilize the surface but possess some protective after-effect. Further improvement of chamber protection methods for AMg6 alloy should apparently involve the selection of synergents for carboxylate-type chamber corrosion inhibitors.

Keywords: vapor-phase metal protection, corrosion inhibitors, chamber inhibitors, aluminum alloy AMg6

Int. J. Corros. Scale Inhib., 2019, 8, no. 2, 257-267 PDF (606 K)
doi: 10.17675/2305-6894-2019-8-2-7

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