Influence of process parameters on the properties of microarc oxide coatings

In this work, oxide coatings on aluminum samples were obtained by the method of micro-arc oxidation at a sinusoidal current in an anode-cathode alloy with an anode and cathode current ratio of 1, with a current approximation of 10.88; 13.99; 17.10; 20.21; 23.32 A/dm² in four electrolytes containing 0.5 g/l NaOH and 80, 90, 100 and 110 g/l Na₂SiO₃. An analytical description of the thickness and porosity dependence of micro-arc oxide coatings on the decrease in current, treatment time, and electrolyte components detection in the form of empirical regression formulas is obtained. Based on the obtained equations a technology for the formation of micro-arc oxide coatings with desired properties was proposed. As a result of experimental verification, the reproducibility of the technology for obtaining micro-arc oxide coatings with a thickness of 25 μm and minimal porosity (P = 19.5%) was confirmed. The relative error of the appearance reproducibility does not exceed ± 0.5%. The results of the study were used in the development of intelligent algorithms that underlie the digital twin of the micro-arc oxidation process.