INFLUENCE OF THE METHOD OF ELECTROLYTIC POLISHING, MECHANICAL TREATMENT AND PURITY OF THE BASE METAL SURFACE ON THE STRENGTH OF BONDING BY ELECTROLYTIC DEPOSITS OF IRON

Abstract

In the present work, the influence of the composition of the electrolyte and the duration of electropolishing of the base metal on the strength of adhesion to iron deposits was studied, and the method of mechanical treatment before applying electrolytic coatings was shown to determine not only the microgeometry of the surface, but also the physicochemical state of the metal in the surface layer, thereby affecting the protective properties. oxide film. On the other hand, the type of machining affects the cost of restoring and coating parts. Therefore, it is practically important to determine the effect of the method of machining and the surface finish of the base metal on the adhesion strength with electrolytic iron deposits. Along with mechanical action, chemical processes play an important role in polishing. The surface of the metal is covered with thin, invisible oxide or salt films under the influence of the environment and the chemically active substances contained in the polishing pastes. When polishing, the film is removed, but on the exposed areas of the metal it is formed again. The hardness of abrasive grains during polishing is not as important as during grinding, since in the first case the abrasive removes a thin film that is less durable than metal. In the process of manufacturing parts by mechanical polishing, traces of processing in the form of small irregularities remain on their surface. The magnitude of these microroughness’s determines the surface finish of the parts. This characteristic has a great influence on the quality of the finish and the performance properties of the products. The smoother the metal surface, the better it resists corrosion. Improving the surface finish increases the wear resistance of the parts. Obtaining shiny surfaces is also associated with the need to remove microroughness. It has been determined that the cleanliness of the surface treatment of parts before electroplating is determined by their purpose and type of coating. Surface cleanliness depends on how the parts are prepared before electroplating. Polishing products with a lower initial surface finish significantly increases the processing time, which reduces the productivity of the equipment. It has been established that electrochemical and chemical polishing have several advantages over mechanical polishing. They do not require the physical effort of the worker, which reduces the complexity of finishing operations. Many products of various shapes and sizes can be processed simultaneously, which is not feasible when polishing with circles. Electrochemical polishing has become more widespread in industry. With its help, a greater smoothing and more intense gloss of the metal surface is achieved than with chemical polishing. The use of this process in preparation for electroplating reduces the number of operations and transitions and improves product quality by increasing the adhesion strength of the coating to the base metal. Keywords: Machining, surface finish, electropolishing, electrolyte, roughness, adhesive strength, iron precipitation, iron plating.