Structural Engineering and Mechanical Properties of (Ti-V-Zr-Nb-Hf-Ta)N Coatings Obtained at Different Pressures

Authors O.V. Sobol´1 , A.A. Andreev2 , H.O. Postelnyk1, A.A. Meylekhov1 , Yu.Ye. Sagaidashnikov1 , V.A. Stolbovoy2 , N.S. Yevtushenko1, T.O. Syrenko3 , Zh.V. Kraievska1, A.V. Zvyagolskiy1

1 National Technical University «Kharkiv Polytechnic Institute», 2, Kyrpychov St., 61002 Kharkiv, Ukraine

2 National Science Center Kharkiv Institute of Physics and Technology, 1, Akademicheskaya St., 61108 Kharkiv, Ukraine

3 Kharkiv Machine-Building College, 79, Plekanivska St., 61068 Kharkiv, Ukraine

Issue Volume 11, Year 2019, Number 3
Dates Received 11 January 2019; revised manuscript received 10 June 2019; published online 25 June 2019
Citation O.V. Sobol´, A.A. Andreev, H.O. Postelnyk, et al., J. Nano- Electron. Phys. 11 No 3, 03013 (2019)
PACS Number(s) 64.75.St, 81.07.Bc, 62.25.-g, 61.05.cp, 61.82.Rx
Keywords High entropy alloys, Nitrogen pressure, Coatings (10) , Texture (2) , Substructural characteristics, Bias potential (2) , Hardness (10) , Abrasive wear.

Effect of pressure of the reaction gas on the texture, structural stress state and mechanical properties (hardness and resistance to abrasive wear) in vacuum-arc coatings based on Ti-V-Zr-Nb-Hf-Ta nitrides of high entropy alloys were investigated in this work. At a bias potential of – 200V, an increase in nitrogen pressure during deposition from 2.5·10 – 4 to 4.5·10 – 3 Torr leads to an increase in the content of nitrogen atoms in the coating, and the formation of a bittexture state [111] + [311] is established. The formation of a biaxial texture occurs due to the presence in alloys of atoms with very different masses (Ti, V and Hf, Ta). The use of a multi-element composition in a single-phase state with a simple cubic lattice allows to achieve high values of microstrain (up to 1.4 %) with a low deposition pressure. It is determined that the increase of nitrogen pressure during deposition leads to an increase in macrostresses. The highest hardness of 53 GPa is achieved in coatings obtained at a pressure of 2·10 – 3 Torr. It has been established that coatings with high resistance to abrasive wear are found to be: crystallite grain size 12-25 nm, absent of texture (or a low level of texture perfection), and also rather high microstrain in crystallites.