Investigation of Plasma Electric Oxide Coating Formed on the Prototype Samples of Aluminum Plates Made of 1050 Grade

Abstract

Today, the technology of hardening the surface layers of parts and the creation of protective coatings on the surface with high physical, mechanical and chemical properties are especially efficient in many industries. The article presents the studies of the most promising innovative technology for surface hardening of 1050 grade aluminum plates by plasma electrolytic oxidation method. This method allows to obtain the materials with an ultra-high melting point, high hardness, and wear resistance. Possible conditions and mechanisms for the formation of protective layers on the surface of aluminum plates to improve reliability and safety in the production of chemical industry products are considered. The influence was studied concerning the main technological parameters (alloying elements, electrical parameters, electrolyte composition) on the properties and structure of oxide ceramic coatings. The qualitative characteristics of the finished products from aluminum alloys and the surface layer of the samples showed the efficiency of the plasma electrolytic oxidation technology, which allows to obtain ceramic coatings with increased hardness, wear and corrosion resistance, and strength. When processing by plasma electrolytic oxidation in an aqueous electrolyte solution, all the industrial safety requirements are met. An alternative approach to processing by plasma electrolytic oxidation is considered, in which 1050 grade aluminum plates were used in a molten nitrate salt at a temperature of 280 °C. The microstructure, phase, chemical composition, and microhardness were studied by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and microhardness tests. The formed coating was found to be free from electrolyte contamination, cracks and pinholes commonly found in coatings formed during plasma electrolytic oxidation treatment in an aqueous electrolyte solution.