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Документ Structure and properties of multi-period vacuum-arc coatings based on chromium nitride(Institute for Single Crystals, 2020) Postelnyk, H. O.; Sobol, O. V.; Kucerova, L.; Dur, OsmanThe properties of multi-period nanocomposite coatings based on chromium nitride are considered. The effect of the negative bias potential on the phase-structural state and mechanical characteristics of the coatings was investigated by X-ray diffractometry combined with the study of hardness by nanoindentation, surface roughness and coefficient of friction during scratch testing. It has been established that all the systems are characterized by the formation of a cubic crystal lattice of the structural type NaCl, as well as the effect of texture on hardness values. For the studied coatings, the hardness is in the range of 20-25 GPa. The presence of texture [311] in CrN/MoN nanocomposite coatings leads to the lowest friction coefficient with a value of about 0.2.Документ Influence of the magnitude of the bias potential and thickness of the layers on the structure, substructure, stress-deformed state and mechanical (TiMo)N/(TiSi)N coatingsl characteristics of vacuum-arc multi-layered(2020) Sobol, O. V.; Postelnyk, H. O.; Meylekhov, A. A.; Subbotina, V. V.; Stolbovoy, V. A.; Dolomanov, A. V.; Kolesnikov, D. A.; Kovaleva, M. G.; Sukhorukova, Yu. V.Layers based on titanium nitride doped with molybdenum and silicon were used to create a multilayer composite. In this case, the mismatch between the lattice periods of (TiMo)N and (TiSi)N layers was about 1%. It was found that in the (TiMo)N/(TiSi)N multilayer composite, such a mismatch of the periods in the constituent layers does not change the single-phase state of the composite even at relatively large layer thicknesses (about 350 nm). The creation of a (TiMo)N/(TiSi)N composite with a nanometer layer thickness allows one to reduce the magnitude of macrostresses (a large value of which is characteristic of single-layer (TiMo)N coatings) and change the substructural characteristics in a wide range of values. It has been established that the use of multi-element (TiMo)N and (TiSi)N layers in a multilayer coating design allows one to achieve a high-hard state with high adhesive strength and good tribological characteristics. The highest properties (hardness – 34.8 GPa and adhesive strength 166.09 N) were achieved in coatings obtained at Ub = -200 V and a layer thickness of 80 nm, which are characterized by compression macrostresses of 7.85 GPa and microstrains 0.75%.Документ Structure and corrosion resistance of vacuum-arc multi-period CrN/Cu, ZrN/Cu and NbN/Cu coatings(2020) Postelnyk, H. O.; Sobol, O. V.; Stolbovoy, V. A.; Serdiuk, I. V.; Chocholaty, O.The structure and properties of vacuum-arc multi-period composite coatings of the MeN/Cu system (where Me is Cr, Zr, and Nb) are studied. It was found that at the smallest nanolayer thickness (about 8…10 nm) of composites in the layers of all systems, only a phase with an fcc lattice is formed, without a pronounced texture in the nitride layers. For ZrN and CrN, the phases with an fcc lattice are equilibrium, and for NbN, they are nonequilibrium. An increase in the thickness of nitride layers leads to the appearance of a texture in ZrN/Cu and CrN/Cu systems and the formation of an equilibrium ε-NbN phase in the layers of the NbN/Cu system. Tests for corrosion resistance in the environment of the formation of chloride ions showed that the coatings are anodic reaction. The best corrosion properties were obtained for coatings with the smallest layer thickness (about 8…10 nm).Документ Structural engineering of NbN/Cu multilayer coatings by changing the thickness of the layers and the magnitude of the bias potential during deposition(2019) Sobol, O. V.; Andreev, A. A.; Stolbovoy, V. A.; Kolesnikov, D. A.; Kovaleva, M. G.; Meylekhov, A. A.; Postelnyk, H. O.; Dolomanov, A. V. ; Sagaidashnikov, Yu. Ye.; Kraievska, Zh. V.To determine the patterns of structural engineering of vacuum-arc coatings based on niobium nitride in the NbN/Cu multilayer composition, the effect of layer thickness and bias potential on the structural-phase state and physico-mechanical characteristics of vacuum-arc coatings was studied. It was found that the metastable δ-NbN phase (cubic crystal lattice, structural type NaCl) is formed in thin layers (about 8 nm thick) regardless of Ub. With a greater thickness of the layers of niobium nitride (in the multilayer NbN/Cu composition), the phase composition changes from metastable δ-NbN to the equilibrium ε-NbN phase with a hexagonal crystal lattice. An increase in the bias potential during deposition from -50 to -200 V mainly affects the change in the preferential orientation of crys-tallite growth. The highest hardness (28.2 GРa) and adhesive resistance is achieved in coatings obtained at Ub = -200 V with the smallest layer thickness. The highest hardness corresponds to the structurally deformed state in which the crystallite texture is formed with the [100] axis perpendicular to the growth surface, as well as a large microstrain (1.5%) in crystallites.Документ The use of negative bias potential for structural engineering of vacuum-arc nitride coatings based on high-entropy alloys(2019) Sobol, O. V.; Andreev, A. A.; Gorban, V. F.; Postelnyk, H. O.; Stolbovoy, V. A.; Zvyagolsky, A. V.; Dolomanov, A. V.; Kraievska, Zh. V.The effect of negative bias potential (Ub = -40, -110, and -200 V) during the deposition of multi-element coatings on their composition, structure and mechanical properties was studied. It was established that during the transition from a multi-element alloy to a nitride, a single-phase state possible to form on its basis (based on the fcc metal lattice, structural type NaCl). In this case, the composition (FeCoNiCuAlCrV)N of coatings with increasing Ub is depleted by the element with the lowest enthalpy of formation of nitride (Cu). In (AlCrTiNbSi)N and (AlCrTiZrNbV)N coatings, the content of low-mass elements (Si and Al) decreases with increasing Ub. In (TiZrHfVNb)N coatings of strong nitride-forming elements with increasing Ub to 200 V, the composition practically does not change. The structure of such coatings is characterized by the presence of a texture with the [111] axis. The presence of weak nitride-forming elements in (FeCoNiCuAlCrV)N coatings leads to the formation of texture [110] for large Ub = 110…200 V. In such coatings, the hardness does not exceed 35 GPa. It is shown that to achieve high hardness at high Ub it is necessary to increase the content in the high-entropy alloy of elements with high nitride-forming ability. In this case, in (TiZrHfVNb)N coatings (made of strong nitride-forming elements with a large mass) at Ub = 200 V, the hardness exceeds 45 GPa.Документ Structural Engineering and Mechanical Properties of (Ti-V-Zr-Nb-Hf-Ta)N Coatings Obtained at Different Pressures(Сумський державний університет, 2019) Sobol, O. V.; Andreev, A. A.; Postelnyk, H. O.; Meylekhov, A. A.; Sagaidashnikov, Yu. Ye.; Stolbovoy, V. A.; Yevtushenko, N. S.; Syrenko, T. O.; Kraievska, Zh. V.; Zvyagolskiy, A. V.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.