Tribological parameters of MAO-layers formed in silicatealkaline electrolyte on samples of high-silicon aluminum alloy AK12

Abstract

The results of the study of the thickness, microhardness and tribological properties (wear intensity and friction coefficient) of the surface layers formed by microarc oxidation (MAO) on the samples of aluminum alloy AK12 are presented. A fractional factorial experiment was planned and conducted. As the factors used electrical parameters of the installation (condenser capacity) and the composition of the electrolyte (concentration of potassium hydroxide-KOH and sodium metasilicate - Na2SiO3). It was found that the MAO-layer increases the wear resistance of the surface in the "dry" friction more than 1.68 times. The lowest wear rate is observed on the layers formed at the maximum concentration of electrolyte components and with a minimum condenser capacity of the installation. Average values of the friction coefficient of the samples in the "dry" friction made fтр = 0,45-0.60. The greatest influence on the microhardness of the MAO layer is the concentration of sodium metasilicate in the electrolyte. To obtain the maximum thickness of the coating, it is necessary to increase of the concentration of electrolyte components and the condenser capacity of the installation.