Triazoles as a class of multifunctional corrosion inhibitors. Review. Part III. 1,2,3-Benzotriazole and its derivatives. Aluminum alloys

• Yu.I. Kuznetsov

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

Abstract: This article continues the review of studies (mainly for 2005–2020) on 1,2,3-benzotriazole (BTA) and its derivatives as corrosion inhibitors (CIs) of various metals from aqueous solutions in a wide pH range. However, only studies on the effect of these organic CIs on the corrosion and electrochemical behavior of aluminum and mainly its alloys are covered here. In contrast to the previously considered metals protected by these CIs (Cu, Zn, Fe), their alloys and steels, the protective layers formed by BTA and its derivatives are generally not due to hardly soluble complex compounds with the cations of the base metal. In addition to the adsorption of benzotriazoles on aluminum alloys, their ability to block copper and copper-containing intermetallics, which can initiate local corrosion of aluminum itself, plays an important role. The ability of BTA to enhance the protection of aluminum alloys in neutral solutions with other CIs is noted. BTA and its substituted derivatives can be very useful in obtaining protective conversion coatings on copper-containing aluminum alloys. Since direct incorporation of CI into coatings can cause their undesirable chemical interaction with the binder and other process additives, BTA and its derivatives can first be incorporated into nano- or microcontainers made of a neutral material, and only then such containers are incorporated into paints or other protective coating materials. A brief analysis of the advantages of such coatings containing encapsulated BTA or its substituted derivatives is given. Examples of their use in protective coatings, often called self-healing or “smart” coatings, are given. Although the ability of BTA and its derivatives to slow down acid corrosion of aluminum alloys has been little studied, it has been found that they mainly slow down the cathodic reaction, and incorporation of a substituent into position 5 of BTA enhances its inhibitory properties in hydrochloric acid solutions.

Keywords: corrosion inhibitors, 1,2,3-benzotriazole, aluminum alloys, conversion coatings, nanocontainers, microcontainers

Int. J. Corros. Scale Inhib., 2020, 9, no. 4, 1142-1168 PDF (418 K)
doi: 10.17675/2305-6894-2020-9-4-1

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