Nanostructured surfaces
Nanostructured coatings of high-entropy AlCuCrCoNiFe alloy obtained by physical vapor deposition method with cathode arc evaporation (PVD CAE): Corrosion behavior
Mordyuk B.N., Makarenko S.Yu., Proshak A.V., Volosevich P.Yu.,            Panarin V.Ye., Svavilny M.Ye., Skoryk M.A.
G.V.Kurdyumov Institute for Metal Physics, NAS of Ukraine, 36 Academician Vernadsky Blvd., Kyiv 03142, Ukraine. 
E-mail:mordyuk@imp.kiev.ua

High entropy alloys are prospective materials to produce protective coatings for different low corrosion resistant metallic materials [1]. It was shown that a physical vapor deposition method with cathode arc evaporation (PVD CAE) is effective in this sense [2]. The so-called ‘micro-drop’ regime of evaporation-deposition from the cathode made of the high-entropy alloy of equiatomic composition AlCuCrCoNiFe was used in this work.
TEM observations confirmed that the microstructures of the HEA coatings contained nano-scale and/or ultrafine grains dependently on the regimes of deposition and thermo-physical properties of the substrate materials. The XRD analysis showed a multi-phase microstructure of the deposited coatings. The SEM data showed that chemical compositions of the obtained HEA coatings were almost identical to that of the as-cast HEA alloy used as a cathode. The used improved equipment allowed producing relatively thick (~50 m) homogeneous coatings.
Corrosion behaviors of the nanostructured HEA coatings were analyzed by means of potentiodynamic polarization curves registered in saline solution (3.5% NaCl) [3]. Corrosion resistance of the as-cast AlCuCrCoNiFe HEA and the AlCuCrCoNiFe nanostructured coatings obtained by PVD CAE deposition is observed to be much higher than those for appropriate substrates (low carbon steel and 2024 aluminum alloy) and it is comparable to that of stainless steel [3].

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2.	Nadutov V. M., Proshak A. V., Makarenko S. Yu., Panarin V. Ye., Svavilny M. Ye. Creation and Mössbauer studies of high-entropy physical vapor deposition by cathode arc evaporation (PVD CAE) coating AlFeCoNiCuCr // Mater Sci Eng Technol.- 2016.- 47.- P. 272-277.
3.	Mordyuk B.N., Prokopenko G.I., Vasylyev M.A., Iefimov M. O. Effect of structure evolution induced by ultrasonic peening on the corrosion behavior of AISI 321 stainless steel // Mater Sci Eng. A 2007.- 458.- P. 253-261.