Diffusion Saturation of U8A Steel in a Mixture of Metal Powders with the Chloride Ammonia

Authors V.G. Hignjak1 , T.V. Loskutova1 , G.Y. Calashnicov1, I.S. Pohrebova1 , N.S. Nikitina1, N.A. Kharchenko2 , Т.P. Hоvоrun2 , I.Y. Smokovych3

1 National Technical University of Ukraine, 37, Prosp. Peremohy, 03056 Kyiv, Ukraine

2 Sumy State University, 2, Rimsky Korsakov St., 40007 Sumy, Ukraine

3 Otto-von-Guericke University Magdeburg, 2b, Universitätsplatz, 39106 Magdeburg, Germany

Issue Volume 11, Year 2019, Number 3
Dates Received 22 March 2019; revised manuscript received 11 June 2019; published online 25 June 2019
Citation V.G. Hignjak, T.V. Loskutova, G.Y. Calashnicov, et al., J. Nano- Electron. Phys. 11 No 3, 03022 (2019)
DOI https://doi.org/10.21272/jnep.11(3).03022
PACS Number(s) 81.65.Lp, 68.55.Nq, 62.20.Qp, 32.30Rj
Keywords Diffusion coatings, Titanium (10) , Aluminum, Сhromium, Microstructure (21) , Phase composition (3) , Wear resistance (2) , Microhardness (2) .

Influence of the composition of the saturated mixture of the titanium, aluminum, chromium and chloride ammonia powders, the previous nitriding in a dissociation ammonia medium, titanium nitride layer saturated before the titanium alumina by the method of physical deposition from the gas phase on the phase, chemical composition and properties of the coatings was established. The main differences in the phase composition of the obtained coatings from the ordinary ones are due to the presence of a barrier layer, in which TiN titanium nitride was used. It has been established that the barrier properties of the titanium nitride layer are the inhibition of the diffusion penetration into the aluminum base, which prevents the formation of the Fe(Al) layer, hence positively affects the properties of the coatings. In this work, two groups of coatings were investigated: the first – TiN, TiС, FeTi, TiAlCr, -phase; the other is TiN, TiC, Cr7C3. The highest microhardness was found for titanium carbide layers – 32.1-35.6 GPa and for titanium nitride – 20.5-24.5 GPa. The resulting coatings contribute to the growth of wear resistance of U8A steel in the conditions of slip friction without lubrication increases compared with the original (61HRC) 3.1-13.3 times. The phase composition of titanium nitride and carbide and chromium carbide coatings showed the best results. The obtained coatings showed high heat resistance due to the formation of complex oxides on the surface with the participation of the titanium, aluminum, chromium. The highest heat resistance at a temperature of 1000 °C for 100 h was detected for U8A steel coated with TiN, TiC, FeTi, TiAlCr, -phase (layers listed from the base to the surface) with a concentration of chromium and aluminum on the surface, respectively, of 50.0 and 14.5 % by mass. The resulting coatings can be used to increase the service life of the U8A steel tools.

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