Corrosion and Physicomechanical Properties of the Coatings on Ak12m2mgn Alloy Formed by Plasma-Electrolytic Oxidation

We propose efficient regimes of the formation of mixed-oxide conversion coatings by plasma-electrolytic oxidation (PEO) of aluminum alloys in pyrophosphate and alkaline electrolytes. It is shown that the variations of the concentrations of electrolyte components and the parameters of PEO (current density and the duration of treatment) lead to the appearance of oxide coatings formed by the material of the metal matrix and oxides of transition metals of various compositions and morphologies, which definitely affect their functional properties. Mixed oxide coatings formed as a result of PEO are characterized by microglobular structures, small sizes of conglomerates, and elevated microhardness. Moreover, they are corrosion and wear resistant. In view of the microglobular structure of the surface and the composition of Al Al2O3 center dot MnO(x)and Al Al2O3 center dot CoO(x)oxide coatings, we can expect that the obtained materials may exhibit catalytic activity in the redox reactions with participation of oxygen and, in particular, in the working processes running in internal-combustion engines.