Ufa University of Science and Technology, Ufa, Russia

N. Yu. Dudareva, Professor at the Department of Internal Combustion Engines, Chief Researcher, Doctor of Technical Sciences, Associate Professor, e-mail: dudareva.nyu@ugatu.su

L. I. Zaynullina, Associate Professor of the Department of Materials Science and Physics of Metals, Junior Researcher, Candidate of Technical Sciences, e-mail: Zaynullina.LI@yandex.ru

Central Scientific Research Automobile and Automotive Engines Institute NAMI, Moscow, Russia
A. V. Kolomeychenko, Head of the Innovative Technology Department, Centre for Agricultural Engineering, Doctor of Technical Sciences, Professor, e-mail: a.kolomiychenko@nami.ru

Wuhan Textile University, Wuhan, China¹ ; Vladimir State University named after Alexander and Nikolay Stoletovs, Vladimir, Russia² ; National University of Science and Technology MISiS, Moscow, Russia³
V. B. Deev, Professor at the Faculty of Mechanical Engineering and Automation¹, Chief Researcher², Professor at the Department of Metal Forming³, Doctor of Technical Sciences, Professor (Соrresponding Autor), e-mail: deev.vb@mail.ru

This paper looked at the effect of the chemical composition of aluminium alloys on the structure and properties of coatings formed by micro-arc oxidation. Thus, the thickness of the formed layer, as well as its porosity and corrosion resistance were determined. Specimens of aluminium alloys with different concentrations of silicon were used for all studies: a hypoeutectic alloy AK4-1 with Si 0.4% and a foreign-made hypereutectic alloy M244 with Si 26%. Micro-arc oxidation was performed in the same mode in a silicatealkaline electrolyte in a capacitor unit for 2 hours. SEM images were used for a structural study of the resulting coatings. The porosity of the coatings was determined by image processing in ImageJ. The corrosion resistance of the specimens was analyzed based on the mass rate of corrosion. For this, the specimens were submerged in a corrosive solution. Analysis of the obtained results showed that the silicon in the aluminium alloy causes a high poro sity of the coatings formed. Silicon was found to influence the behaviour of the electric parameters of the process by bringing up the anode current value while not affecting the thickness of the coating. Analysis of the photographs of microsections showed that the layer formed on AK4-1 alloy has higher density and low porosity, but it also has through cracks. Irrespective of porosity, the corrosion resistance of coated specimens is almost the same. Due to the presence of such layer, the corrosion resistance of the AK4-1 specimens increased by 1.72 times, whereas for the M244 specimens it is 1.2 times lower.

This research was funded under Governmental Assignment No. FEUE-2023-0007 (UUST) by the Ministry of Science and Higher Education of the Russian Federation.

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