Technology of obtaining composite conglomerate powders for plasma spraying of high-temperature protective coatings

OBRABOTKAMETALLOV Vol. 23 No. 1 2021 18 TECHNOLOGY Technology of obtaining composite conglomerate powders for plasma spraying of high-temperature protective coatings Boris Guzanov 1, a , Natalia Pugacheva 2, b , Evgeniy Slukin 3, c , Tatiana Bykova 2, d * 1 Russian State Vocational Pedagogical University, 11 Mashinostroiteley str., Ekaterinburg, 620012, Russian Federation 2 Institute of Engineering Science, Ural Branch of Russian Academy of Sciences, 34 Komsomolskaya str., Ekaterinburg, 620049, Russian Federation 3 Ural Federal University named after the fi rst President of Russia B.N. Yeltsin, 19 Mira str., Ekaterinburg, 620002, Russian Federation a https://orcid.org/0000-0001-5698-0018, guzanov_bn@mail.ru, b https://orcid.org/0000-0001-8015-8120, nat@imach.uran.ru , c https://orcid.org/0000-0003-4807-5135, slukin@cniim-ekt.ru, d https://orcid.org/0000-0002-8888-6410, tatiana_8801@mail.ru Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2021 vol. 23 no. 1 pp. 6–20 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2021-23.1-6-20 Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov ARTICLE INFO Article history : Received: 29 October 2020 Revised: 18 November 2020 Accepted: 14 December 2020 Available online: 15 March 2021 Keywords : Coatings Plasma spraying Powder Fraction Binder Solvent Conglomerate Funding The work was carried out with partial funding under the theme No. АААА - А 18-118020790145-0 of the Ministry of Education and Science of the Russian Federation. ABSTRACT Introduction. For parts of gas turbines operating under conditions of corrosion-erosion and intense wear, the most acceptable are compositions containing Ni, Co, Cr, Al, B, Y both in pure form and in the com- position of compounds applied on the contact surface during thermal spraying. Modern integrated complexes obtained by combining dissimilar substances in the form of a single composition are promising. Such powders are obtained either by cladding or by conglomeration of fi nely dispersed starting components into a larger particle. The problem of developing and manufacturing plants for conglomeration of powders is urgent and practically important, since it makes it possible to obtain material for thermal spraying of coatings for high- temperature purposes. The aim of the work is to develop a technological scheme for obtaining powders of the required chemical composition with a given particle shape and size, intended for spraying high-temperature protective coatings. Materials and research methods . A technology is developed for the production of inte- grated powders for spraying coatings using the method of spray drying and subsequent sintering in vacuum or in an argon-hydrogen atmosphere, which avoids the loss of feedstock due to the return of fi ne and coarse fractions. A technology for preparing materials for spray drying and granulation is proposed. A gravity type aerodynamic classi fi er is designed and manufactured, which makes it possible to select automatically the powder fraction necessary for spraying the coating, as well as return the unwanted fraction for recycling. The morphology of the granular powder is determined using a TESCAN scanning electron microscope. The chemical composition of the resulting integrated complexes is determined by X-ray microanalysis on an OX- FORD attachment. Results and discussion. The technological conditions for obtaining powders of a given size (40…100 μ m) are established. It is shown that the shape of the conglomerate particles after spray drying is close to spherical. On the basis of a multifactor experiment, the optimization of the technological process for obtaining powders Ni-17Cr-10Al-1Y and Ni-22Cr-16Al-1Y with sizes up to 100 μ m is performed. It is shown that when conglomerating powders with increased aluminum content (Ni-22Cr-16Al-1Y), it is neces- sary to take into account the exothermic reaction of nickel aluminide formation and dilute the mixture of initial components before sintering with the fi nished sintered powder. The resulting integrated complexes are characterized by high heat resistance; therefore they are designed and successfully used for plasma spraying of protective coatings for high-temperature purposes. Conclusions. A technology is developed for obtaining composite conglomerated powders Ni-17C-10Al-1Y and Ni-22Cr-16Al-1Y with particle sizes up to 100 μ m and a shape close to spherical. A distinctive feature of this technology is that it avoids the loss of feedstock by returning fi ne and coarse fractions. For citation: Guzanov B.N., Pugacheva N.B., Slukin E.Yu., Bykova T.M. Technology of obtaining composite conglomerate powders for plasma spraying of high-temperature protective coatings. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science , 2021, vol. 23, no. 1, pp. 6–20. DOI: 10.17212/1994-6309-2021-23.1-6-20. (In Russian). ______ * Corresponding author Bykova Tatiana M., Ph.D. (Engineering), Scienti fi c associate Institute of Engineering Science, Ural Branch of Russian Academy of Sciences, 34 Komsomolskaya str., 620049, Ekaterinburg, Russian Federation Tel.: 8 (343) 362-30-43, e-mail: tatiana_8801@mail.ru