Study of the mechanism of formation of styrene-acrylic conversion coatings on magnesium and aluminum alloys

• Yu.B. Makarychev, O.Yu. Grafov and D.B. Vershok

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31-4, Leninsky prospect, 119071 Moscow, Russian Federation

Abstract: The mechanism of formation of styrene-acrylic conversion coatings on magnesium and aluminum alloys was studied. It was found that styrene-acrylic dispersions form porous structures with good adhesion to the metal upon coalescence on the surface of magnesium alloys. The physicochemical properties of polymer porous coatings were investigated by X-ray photoelectron spectroscopy and EIS. It was shown that the chemical polycondensation reaction between acrylic acid and magnesium hydroxides results in the formation of organomagnesium micelles in the styrene-acrylic polymer shell. It was observed that porous structures on magnesium alloys arise as a result of coalescence of organomagnesium micelles upon polymerization of styrene-acrylic dispersions. On AMg-3 alloy, organomagnesium compounds are formed on the inner boundary of the polymer coating due to magnesium contained in the aluminum alloy. Studies of the mechanical strength and adhesion force of coatings to the metal were carried out. It was found that the formation of organomagnesium compounds at the interface with the metal increases the adhesion of styrene-acrylic coating on magnesium and aluminum alloys by about an order of magnitude. It was shown that acrylic dispersions can be used to obtain cost-effective conversion coatings on magnesium and aluminum alloys that improve the adhesion of paint materials to the metal.

Keywords: adhesion strength, magnesium alloys, X-ray photoelectron spectroscopy, conversion coatings, paints, corrosion inhibitors

Int. J. Corros. Scale Inhib., 2025, 14, no. 1, 381-396
doi: 10.17675/2305-6894-2025-14-1-23

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