Surface modification of aluminum alloy 6063 with trialkoxysilane solutions

• A.M. Semiletov and Yu.I. Kuznetsov

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

Abstract: The superhydrophobic (SHP) films on metal surfaces are the most important class of multifunctional coatings with a number of useful properties: anti-corrosion, anti-fouling, self-cleaning and anti-icing. To obtain the anticorrosive SHP coatings, a method is used that combines a preliminary surface preparation with subsequent modification with a hydrophobic agent. It is important that the creation of a specific surface texture is a necessary condition for obtaining stable SHP coatings. In this article, we consider the possibility of obtaining the protective films of on a smooth and laser-textured surface of 6063 aluminum alloy. It is shown that the laser treatment of the alloy and subsequent modification in solutions of vinyltrimethoxysilane, octyltriethoxysilane, and octadecyltrimethoxysilane leads to SHP of the surface. The results degradation of SHP state of the alloy in water indicate a greater stability of the films formed from solutions of hydrophobic trialkoxysilanes: octyltriethoxysilane and octadecyltrimethoxysilane. The protective ability of SHP coatings was evaluated by polarization measurements, electrochemical impedance spectroscopy and corrosion test in a salt spray chamber. The electrochemical tests of the samples in a sodium chloride solution showed that the SHP films effectively prevented local depassivation. It has been established that SHP films formed from a solution of octadecyltrimethoxysilane have the best anticorrosive properties, and the time until the appearance of the first corrosion damage in a salt spray test is τ_cor=32 days.

Keywords: aluminum, corrosion, superhydrophobization, trialkoxysilanes

Int. J. Corros. Scale Inhib., 2022, 11, no. 1, 293-306
doi: 10.17675/2305-6894-2022-11-1-17

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