Obrabotka Metallov 2019 Vol. 21 No. 4

OBRABOTKAMETALLOV Vol. 21 No. 4 2019 67 MATERIAL SCIENCE Hydrothermal Deposition of С/MoS 2 on Electrospark Fe-Al Coatings for AISI 304 Stainless Steel Alexander Burkov a, * , Pavel Chigrin b , Maria Kulik c Institute for Material Studies, Khabarovsk Scientific Center, Far Eastern Branch of Russian Academy of Sciences, 153 Tikhookeanskaya st., Khabarovsk, 680042, Russian Federation a https://orcid.org/0000-0002-5636-4669, burkovalex@mail.ru , b https://orcid.org/0000-0002-1560-489X , pal_chig@mail.ru , c https://orcid.org/0000-0002-4857-1887 , marijka80@mail.ru Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2019 vol. 21 no. 4 pp. 59–69 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2019-21.4-59-69 Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov ARTICLE INFO Article history : Received: 19 July 2019 Revised: 20 August 2019 Accepted: 14 September 2019 Available online: 15 December 2019 Keywords : Stainless steel AISI 304 Coating Electrospark deposition Iron aluminide Hydrothermal synthesis Molybdenum sulfide Wear resistance Funding The study is supported by the Khabarovsk Territory Government (Decree No. 476-rp of June 10, 2019). Acknowledgements The authors are grateful to the Center for Collective Use of the “National Research Center for Marine Biology named after A.V. Zhirmunsky” Far Eastern Branch of the Russian Acad- emy of Sciences for help in conducting Raman studies and personally senior scientist, candidate of biological sci- ences A.A. Karpenko. ABSTRACT Introduction. Improving the tribological properties of stainless steels can be achieved by creating anti-friction coatings. The purpose of the work is a research of the structure and wear resistance of composite electrospark coatings made of Fe-Al intermetallic compounds with pores filled with C/MoS 2 . Methods. In this work, the coatings of Fe-Al intermetallic compounds are obtained on AISI 304 stainless steel by the method of electrospark deposition in a mixture of granules consisting of iron and aluminum. Five mixtures of granules with aluminum content from 20 to 100 mol % are prepared. In order to increase the porosity of intermetallic coatings, it was etched in a 20% alkali solution. To fill the porous surface of samples with amorphous carbon and molybdenum disulfide, the method of hydrothermal synthesis is applied in two stages: in a glucose solution at 160 °C, and in a solution of thiourea and sodium molybdate at 220 °C. The structure of the coatings is studied by X-ray diffraction analysis, scanning electron microscopy, X-ray microanalysis and Raman spectroscopy. The wear resistance of the coatings is investigated according to ASTM G99-04 technique with dry sliding friction using counter bodies in the form of disks made of high-speed steel R6M5 at a speed of 0.47 m/s under loads of 10 and 50 N. Results and discussion. It is established that with an increase of the aluminum content in the granules mixture, the phase composition of intermetallic coatings changes from FeAl to Fe 14 Al 86 . It is shown that the etching of intermetallic coatings is accompanied by the expansion of transverse cracks and the appearance of pores that further are filled with carbon and with molybdenum disulfide. Friction coefficient is in range of 0.26-0.46. The wear rate of Fe-Al-C-MoS 2 coatings is in the range of 1.1-9 ∙ 10 –5 mm 3 /Nm, which is 3-22.5 times lower than one of AISI 304 steel. The best wear resistance is expectedly demonstrated by coatings prepared in the medium of granules with the highest aluminum content. For citation: BurkovA.A., Chigrin P.G., Kulik M.A. Hydrothermal deposition of С/MoS 2 on electrospark Fe-Al coatings for AISI 304 stainless steel. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science , 2019, vol. 21, no. 4, pp. 59–69. DOI: 10.17212/1994-6309-2019-21.4-59-69. (In Russian). ______ * Corresponding author Burkov Alexander A. , Ph.D. (Physics and Mathematics), Institute for Material Studies, Khabarovsk Scientific Center, Far Eastern Branch of Russian Academy of Sciences, 153 Tikhookeanskaya st., 680042, Khabarovsk, Russian Federation Tel.: +79141618954 , e-mail: burkovalex@mail.ru