Effect of microarc oxidation regimes on corrosion resistance of coatings formed on piston aluminum alloys

Abstract

The effect of the concentration of a silicate-alkaline electrolyte and electric modes of process micro-arc oxidation on the corrosion resistance of the surfaces formed on aluminum alloys of different chemical composition was investigated. Alloys traditionally used for the manufacture of pistons of internal combustion engines (ICE) were analyzed. The corrosion resistance was investigated in solution, the composition of which to the greatest extent close to the conditions of cylinder-piston group of internal combustion engines. The corrosion resistance of the samples was estimated by the mass rate of corrosion during their exposure in corrosive solution for 144 hours. The regression equations linking the concentration values of the electrolyte and of technological modes of MAO with the corrosion rate was obtained. It is established that the conditions of the process significantly influence the corrosion resistance of the coatings. Surface treatment by the method of MAO increases a corrosion resistance by 2.9..31.9 times, depending on the sample alloy and MAO modes.