Octadecylamine, 1,2,3-benzotriazole and a mixture thereof as chamber inhibitors of steel corrosion

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

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

Abstract: It has been shown that it is possible to create a technology for efficient protection of steel items by short-term treatment in vapors of low-volatile corrosion inhibitors in specialized chambers at elevated temperatures. It is suggested to call this technology based on the protection after-effect of adsorbed inhibitor films as “chamber treatment” and the compounds used therein as “chamber inhibitors”. A number of methods (accelerated and field corrosion tests, potentiodynamic polarization measurements, ellipsometry, surface wetting angle measurement) were used to study the formation of adsorption films of 1,2,3-benzotriazole (BTA), octadecylamine (ODA), and a mixture thereof on steel from a gas phase. It has been found that the temperature plots of the protection after-effect of the inhibitors studied have a maximum at 120°C. The adsorption films that stabilize the passive state of steel (both in the absence of chloride and in chloride-containing electrolytes) and noticeably hydrophobize the surface are already formed within one hour of chamber treatment. The adsorption films of ODA and its mixtures with BTA hinder steel corrosion initiation under conditions of recurrent moisture condensation more than 100-fold and have significantly better protective properties than the adsorption films of BTA. It has been found that adsorption of inhibitors hinders the thermal oxidation of steel. The total thickness of the surface layers on steel (oxide film and adsorbed inhibitor) responsible for the protection after-effect depends on the inhibitor nature but does not exceed 15 nm. It has been shown that treatment in vapors of ODA or its mixture with BTA markedly increases the corrosion resistance of low-carbon steel under weathering conditions and can be used for the interoperational protection of metal items.

Keywords: corrosion inhibitors, vapor-phase protection, temporary protection, chamber treatment

Int. J. Corros. Scale Inhib., 2018, 7, no. 2, 203-212 PDF (653 K)
doi: 10.17675/2305-6894-2018-7-2-7

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