Факультет технічних систем і енергоефективних технологій (ТеСЕТ)
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Item Composition, Structure, and Properties of Ti, Al, Cr, N, C Multilayer Coatings on AISI W1-7 Alloyed Tool Steel(MDPI, 2022) Loskutova, T.; Hatala, M.; Pogrebova, I.; Nikitina, N.; Bobina, M.; Radchenko, S.; Харченко, Надія Анатоліївна; Харченко, Надежда Анатольевна; Kharchenko, Nadiia Anatoliivna; Kotlyar, S.; Павленко, Іван Володимирович; Павленко, Иван Владимирович; Pavlenko, Ivan Volodymyrovych; Іванов, Віталій Олександрович; Иванов, Виталий Александрович; Ivanov, Vitalii OleksandrovychNew methods of diffusion metallization of AISI W1-7 steel have been developed. The paper proposes a comparative analysis of the properties and characteristics of AISI W1-7 steel after three methods of chemical heat treatment: diffusion nitriding, nitrogen titration by physical deposition from the gas phase, and diffusion chromium plating with subsequent titanium alloys. The results are presented as a comprehensive analysis of coatings: metallographic, micro-X-ray spectral, X-ray phase, durometric, heat resistance, and wear resistance. It is established that multilayer protective coatings are formed as a result of treatments. It is shown that the coatings consist of carbide and nitride zones, intermetallic, and an Al2O3 layer outside the coating. The coatings have been found to contain barrier layers that prevent aluminum from penetrating the substrate. The maximum microhardness is typical for layers based on titanium carbide—30.3–35.5 GPa and titanium nitride—22.0–22.6 GPa, heat-resistant steels AISI W1-7 at a temperature of 900 °C in 4.2–8.5 times and wear resistance under sliding friction without lubrication up to 5.4 times compared to samples without treatment.Item Electric-Spark Alloying of Metal Surfaces with Graphite(G. V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine, 2022) Tarelnyk, V. B.; Гапонова, Оксана Петрівна; Гапонова, Оксана Петровна; Haponova, Oksana Petrivna; Konoplianchenko, Ye.V.The article reviews and analyses the current scientific research in the field of surface treatment of metal surfaces with concentrated energy fluxes (CEF) — the electric-spark (in the literature, known also as electrospark) alloying (ESA), which makes it possible to obtain surface structures with unique physical, mechanical and tribological properties at the nanoscale. The ESA method with a graphite electrode (electrospark carburizing — EC) is based on the process of diffusion (saturation of the surface layer of a part with carbon), and it is not accompanied by an increase in the size of the part. In this article, the influence of the EC parameters on the quality of the carburized layer is investigated. The microstructural analysis shows that the three characteristic zones could be distinguished in the structure: the carburized (‘white’) layer, the finely dispersed transition zone with fine grain, and the base metal zone. The analysis of the results of the durometric studies of the coatings is carried out. To achieve the required parameters of dimensional accuracy and roughness of the working surface of the part after the EC process, it is necessary to use the method of non-abrasive ultrasonic finishing (NAUF). In addition, because of applying the NAUF method, the surface roughness is decreased, the tensile stresses are changed to the compressive ones, and the fatigue strength is increased too. In addition, to reduce the roughness of the treated surface, it is proposed to apply the EC technology in stages, reducing the energy of the spark discharge at each subsequent stage. In order to increase the quality of the carburized layer obtained by the EC process, it is proposed to use a graphite powder, which is applied to the treated surface before alloying. The comparative analysis shows that, after the traditional EC process at Wp = 4.6 J, the surface roughness of steel 20 is Ra = 8.3–9.0 μm, and after the proposed technology, Ra = 3.2–4.8 μm. In this case, the continuity of the alloyed layer increases up to 100%; there increases the depth of the diffusion zone of carbon up to 80 μm as well as the microhardness of the ‘white’ layer and its thickness, which increase up to 9932 MPa and up to 230 μm, respectively. The local micro-x-ray spectral analysis of the obtained coatings shows that, at the EC process carried out in a traditional way, the applying Wp = 0.9, 2.6, 4.6 J provides the formation of the surface layers with high-carbon content depths of 70, 100, 120 μm, respectively, and with the use of a graphite powder, they are of 80, 120, 170 μm. While deepening, the amount of carbon is decreasing from 0.72–0.86% to the carbon content in the base metal — 0.17–0.24%. In the near-surface layer formed with the use of the new technology, the pores are filled with free graphite, which could be used as a solid lubricant to improve the operating characteristics of the friction-pairs parts processed thereby.Item Wear Resistance Improvement of Linear Block-Polyurethanes Under Conditions of Liquid Friction(Sciendo, 2021) Panda, A.; Anisimov, V.M.; Anisimov, V.V.; Дядюра, Костянтин Олександрович; Дядюра, Константин Александрович; Diadiura, Kostiantyn OleksandrovychA significant disadvantage of parts made of linear block polyurethanes under conditions of friction contact in the presence of an aqueous medium is the intensification of hydrolysis processes and decrease in volume strength. It was proposed to slow down the hydrolysis of polyurethanes in three ways: by directed changes in chemical struc-ture, by electromagnetic radiation of different intensities and by creation of composite materials, based on the principle of additional intermolecular crosslinking at the manufacturing and hot processing stages. The conditions for the formation of a smooth wear-resistant surface that protects the material from rapid destruction are re-vealed.Item Increasing of wear resistance of linear block-polyurethanes by thermal processing methods(MM Science Journal, Czech Republic, 2021) Panda, A.; Anisimov, V.M.; Anisimov, V.V.; Дядюра, Костянтин Олександрович; Дядюра, Константин Александрович; Diadiura, Kostiantyn Oleksandrovych; Pandova, I.A significant imperfection of parts made from linear block polyurethanes under conditions of friction contact in the presence of water medium is an intensification of hydrolysis processes and reduction of bulk strength. In order to slow down the hydrolysis process, samples of the polyurethanes were subjected to three types of thermal impacts: thermal processing during some time, infrared and laser irradiation. It has been established that processing in thermal fields of different intensity allows 5-10 times increase of wear resistance of these materials during friction in water medium.Item About wear resistance of linear block-polyurethanes(MM Publishing, 2020) Anisimov, V.M.; Anisimov, V.V.; Panda, A.; Pandova, I.; Дядюра, Костянтин Олександрович; Дядюра, Константин Александрович; Diadiura, Kostiantyn OleksandrovychLinear block-polyurethanes (BPU) are finding more and more practical applications in industry, and their recipe range is rapidly expanding. It is shown that the evaluation of the tribotechnical characteristics of BPU depending on hardness, as suggested by ISO 16365-1:2014 P1, is inaccurate and requires further research to establish the relationship between structure and properties of polyurethanes, taking into account their chemical structure and the type of initiaal components. The dependences of the tribotechnical characteristics of linear block-polyurethanes under friction with steel without external lubrication and in the liquid on the parameters of structural organization of the polymer were studied: at the molecular level (oligooethers, oligoesters), at the topological level (change in the molecular weight of oligomers from 500 to 2000), at supramolecular level (influence of crystallinity), at the morphological level (content of hard phase). The change in the roughness of steel counterbody during friction of polyurethanes with the content of hard blocks 20%, 50%, and 70% was also studied. A method is proposed for increasing the wear resistance of polyurethanes by thermal diffusion saturation of the surface with silicon carbide particles.Item Abrasion Resistance of S235, S355, C45, AISI 304 and Hardox 500 Steels with Usage of Garnet, Corundum and Carborundum Abrasives(Advances in Science and Technology, 2019) Szala, M.; Szafran, M.; Macek, W.; Марченко, Станіслав Вікторович; Марченко, Станислав Викторович; Marchenko, Stanislav Viktorovych; Hejwowski, T.В статті містяться результати випробувань основних типів сталей при терті по нежорстко закріплених частинках абразиву