Protective coatings on aluminum alloys obtained by microarc oxidation in carbon-containing electrolytes ‒ Review

• A.V. Apelfeld¹ and M.V. Gerasimov²

¹ Rybinsk State Aviation Technical University, Department of Materials Science, Casting and Welding, 152943 Rybinsk, Russia
² Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31-4, Leninsky prospect, 119071 Moscow, Russia

Abstract: The review considers the latest advances in the field of obtaining protective coatings formed by microarc oxidation (MAO) or otherwise plasma electrolytic oxidation on the surface of wrought and cast aluminum alloys of various alloying systems (Al–Mg, Al‒La, Al−Mg−Si, Al−Si−Mg−Mn, Al–Cu–Mg, Al‒Cu‒Mg‒Mn, Al‒Cu–Mg‒Fe‒Ni, Al–Zn–Mg–Cu, Al‒Si, Al‒Si‒Cu, Al‒Si‒Mg, Al‒Si–Ni‒Cu‒Mg) in slurry electrolytes with carbon-containing particles. The addition of carbon-containing (graphite, diamond, nanotubes, fullerenes, graphene and graphene oxide, carbides) micro- and nanoparticles into electrolytes for MAO with their subsequent incorporation into the forming ceramic-like layers makes it possible to obtain multifunctional coatings. Carbon-containing additives affect the microarc oxidation process itself, the thickness, surface morphology, structure, composition and other characteristics of formed MAO coatings. MAO coatings formed in slurry electrolytes exceed coatings obtained in conventional solution electrolytes in a number of characteristics, and their formation rate is increased. Micro- and nanoparticles, when incorporated into the coatings and filling open pores, increase corrosion-protective properties of the formed layers. They also often act as dispersion strengthening or lubricant, enhancing the wear resistance of MAO coatings. Adding carbon-containing particles into the slurry electrolytes also make it possible forming coatings with special properties. Some results of own research are also presented. The review is structured by the type of carbon-containing particles, aluminum alloys, electrolyte composition, MAO treatment parameters and the characteristics of resulting coatings.

Keywords: microarc oxidation (MAO), aluminum alloys, slurry electrolytes, carbon-containing particles, characteristics of MAO coatings

Int. J. Corros. Scale Inhib., 2026, 15, no. 4, 40-82
doi: 10.17675/2305-6894-2026-15-4-2

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