OBRABOTKAMETALLOV Vol. 26 No. 3 2024 264 MATERIAL SCIENCE Structural features and tribological properties of multilayer high-temperature plasma coatings Natalia Pugacheva 1, 2, a, Tatyana Bykova 1, 2, b, *, Vitaly Sirosh 3, c, Alexey Makarov 3, d 1 Institute of Engineering Science Ural Branch, Russian Academy of Sciences, 34 Komsomolskaya str., Yekaterinburg, 620049, Russian Federation 2 Ural Federal University named after the fi rst President of Russia B.N. Yeltsin, 19 Mira str., Ekaterinburg, 620002, Russian Federation 3 M.N. Miheev Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences, 18 S. Kovalevskoy str., Ekaterinburg, 620108, Russian Federation a https://orcid.org/0000-0001-8015-8120, nata5-4@yandex.ru; b https://orcid.org/0000-0002-8888-6410, tatiana_8801@mail.ru; c https://orcid.org/0000-0002-8180-9543, sirosh.imp@yandex.ru; d https://orcid.org/0000-0002-2228-0643, av-mak@yandex.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2024 vol. 26 no. 3 pp. 250–266 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2024-26.3-250-266 ART I CLE I NFO Article history: Received: 31 May 2024 Revised: 22 June 2024 Accepted: 08 July 2024 Available online: 15 September 2024 Keywords: Plasma spraying Multilayer coating Iron oxide Strengthening phases Micromechanical properties Friction coeffi cient Wear resistance Funding The work was carried out within the framework of the state assignment of the IMASH Ural Branch of the Russian Academy of Sciences on topic No. 124020700063-3 on the equipment of the Center for Shared Use “Plastometry”. The work was carried out within the framework of the state assignment of the Institute of Physics and Mathematics, Ural Branch of the Russian Academy of Sciences on the topic “Structure” No. 122021000033-2. ABSTRACT Introduction. Multilayer high-temperature coatings obtained using plasma spraying, are studied. The combination of layers of diff erent chemical and phase compositions made it possible to increase wear resistance by 1.5–2.0 times. The purpose of this work is to study the infl uence of the chemical composition of sprayed coatings on the phase composition, structure, micromechanical and tribological characteristics under conditions of dry sliding friction of surface layers. Materials and methods of research. Coatings A and B consist of sequentially sprayed layers. The fi rst and second layers were sprayed in a reducing atmosphere: the fi rst layer was a heat-resistant selffl uxing powder of two systems: 1 – Fe-Cr-Si-Mn-B-C for coating A and 2 – Fe-Ni-Si-Mn-B-C for coating B; the second layer was a mixture of self-fl uxing powder with iron powder in a 1:1 ratio. The third layer was obtained by spraying iron powder in an oxidizing atmosphere to form a metal oxide coating. To create a layer of scale on the surface, coated specimens were subjected to high-temperature annealing at a temperature of 1,000 ℃. The chemical composition and nature of the distribution of elements over the thickness of the coatings were determined by micro-X-ray spectral analysis using a TWSCAN scanning electron microscope with an Oxford energy-dispersive attachment. Microhardness and micromechanical properties were studied using an instrumental microhardness tester of the Fischerscope HM2000 XYm system at a load of 0.980 N. Determination of tribological properties was carried out on a laboratory installation using the “fi nger-disc” scheme at loads of 30, 75, 100 and 130 N. To measure roughness parameters and obtain 3-D profi lometry of surfaces after testing, a non-contact profi lometer-profi ler Optical profi ling system Veeco WYKO NT 1100 was used. Results and discussion. Metallographic studies have shown that the formed multilayer coatings consist of an internal metal layer and an external oxide layer with a total thickness of the entire coating up to 800–850 μm. It is established that the fi rst sprayed layer has the highest level of microhardness, which is due to the high-volume fraction of the strengthening phases contained in it (~ 95 %). It is shown that the coating A has increased wear resistance, which is expressed by minimal weight loss (~ 1.5 times less than that of the coating of the coatimg B), the friction coeffi cient was f = 0.3 for coating A and f = 0.4 for coating B. The study of wear surfaces has shown that for all selected test loads under sliding friction conditions, the coating of both compositions was preserved, even at a maximum load of 130 N. For citation: Pugacheva N.B., Bykova T.M., Sirosh V.A., Makarov A.V. Structural features and tribological properties of multilayer high-temperature plasma coatings. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2024, vol. 26, no. 3, pp. 250–266. DOI: 10.17212/1994-6309-2024-26.3-250-266. (In Russian). ______ * Corresponding author Bykova Tatiana M., Ph.D. (Engineering), Senior Researcher Institute of Engineering Science Ural UB RAS, 34 Komsomolskaya str., 620049, Yekaterinburg, Russian Federation Tel.: +7 343 362-30-43, e-mail: tatiana_8801@mail.ru References 1. Guzanov B.N., Kositsyn S.V., Pugacheva N.B. Uprochnyayushchie zashchitnye pokrytiya v mashinostroenii [Reinforcing protective coatings in engineering industry]. Ekaterinburg, UrO RAN Publ., 2003. 244 p. ISBN 5-76911405-3. 2. Serin K., Pehle H.J. Improved service life for hot forming tools in seamless tube plants. Stahl und Eisen, 2014, vol. 134 (11), pp. 161–174.
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