Structuring of Surface Films Formed on Magnesium in Hot Chlorobenzotriazole Vapors

Materials. 2022. Vol. 15. No. 19. Article 6625.

Goncharova O., Luchkin A. Y., Ivan N. Senchikhin, Makarychev Y., Luchkina V., Dement’eva O. V., Vesely S. S., Andreev N. N.

Chamberprotection of metals from atmospheric corrosion is a variety of vapor-phase
inhibition. It is based on the effect of adsorption films formed in the vapors of low-volatile corrosion
inhibitors at elevated temperatures. The paper analyzes the specific features of the chamber protection
of a magnesium alloy with chlorobenzotriazole. It has been found that the protective properties
of surface films formed in hot vapors of this compound increase upon exposure of the metal to air.
The processes of structuring of protective films that occur in this case have been studied by a set
of corrosion, electrochemical and physical methods. It has been shown that chamber treatment of
the alloy is accompanied by chlorobenzotriazole adsorption and uniform thickening of the surface
oxide-hydroxide layer. In this case, the corrosion processes slow down by a factor of up to 10.
Prolonged exposure of the samples in air after the chamber treatment results in additional oxidation
of magnesium and hydroxylation of the oxide. However, the oxide-hydroxide layer does not grow
on the entire surface, but as separate islets. Such a change in the structure of the surface films results
in an additional 10-fold increase in the corrosion resistance of the magnesium alloy.

Keywords: scanning electron microscopy, EIS, passivity, magnesium alloy, atmospheric corrosion, structuring of surface films, corrosion inhibitors