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Документ The Use of Negative Bias Potential for Structural Engineering of Vacuum-Arc Nitride Coatings Based on FeCoNiCuAlCrV High-Entropy Alloy(Sumy State University, 2018) Sobol, O. V.; Andreev, A. A.; Gorban, V. F.; Meylekhov, A. A.; Postelnуk, A. A.; Stolbovoy, V. A.; Zvyagolskiy, A. V.The effect of negative bias potential (Ub = – 40, – 110, and – 200 V) upon the deposition of multielement coatings on their composition, structure, and mechanical properties was studied. It is shown that when using a high-entropy multielement (of 7 elements) FeCoNiCuAlCrV alloy, it is possible to obtain a single-phase nitride (FeCoNiCuAlCrV)N. Nitride has an fcc crystal lattice (structural type NaCl). It has been established that with an increase in Ub in the structural state occurs transition from practically nontextured (polycrystalline) to the preferential orientation of the growth of crystallites with the [111] texture axis (at Ub = – 110 V) and [110] (at Ub = – 200 V). This is accompanied by a decrease in the lattice period, as well as a decrease in hardness and modulus of elasticity. For coatings (FeCoNiCuAlCrV) N, the highest hardness of 38 GPa is achieved by using the smallest (– 40 V) bias potential during the deposition process. It is shown that to achieve high hardness at high Ub it is necessary to increase the content in the highentropy alloy of elements with high nitride-forming ability.Документ Structure and Properties of Vacuum-arc Coatings of Chromium and Its Nitrides Obtained under the Action of Constant and Pulse High-voltage Bias Potential(Sumy State University, 2017) Sobol, O. V.; Postelnyk, A. A.; Mygushchenko, R. P.; Al-Qawabeha, Ubeidulla F.; Tabaza, Taha A.; Al-Qawabah, Safwan M.; Gorban, V. F.; Stolbovoy, V. A.To reveal the regularities of structural engineering of vacuum-arc coatings based on chromium and its nitrides, the influence of the main physicotechnological factors (the pressure of the nitrogen atmosphere and the bias potential) in the formation of coatings was studied. It was discovered that during the deposition of chromium coatings the formation of the texture axis [100], as well as the macrodeformation of compression is happening. The supply of a high-voltage negative pulse potential to the substrate increases the mobility of the deposited atoms and leads to relaxation of the compression deformation. As the pressure increases from Torr, the phase composition of the coatings changes: Cr (JCPDS 06-0694) → Cr2N(JCPDS 35-0803) → CrN(JCPDS 11-0065). The supply of high-voltage pulses leads to the formation of a texture of crystallites with parallel growth surfaces planes having d ≈ 0.14 nm. The structure obtained by pulsed high-voltage action makes it possible to increase the hardness of the coating to 32 GPa and reduce the friction coefficient to 0.32 in the "chromium nitride-steel" system and to 0.11 in the "chromium nitride-diamond" system. The results obtained are explained from the viewpoint of increasing the mobility of atoms and the formation of cascades of displacements when using an additional high-voltage potential in the pulse form during the deposition of chromium-based coatings.Документ Influence of the Bias Potential and the Pressure of the Nitrogen Atmosphere on the Structure and Properties of Vacuum-arc Coatings Based on the AlCrTiZrNbV High-entropy Alloy(Sumy State University, 2018) Sobol, O. V.; Andreev, A. A.; Gorban, V. F.; Postelnyk, A. A.; Stolbovoy, V. A.; Zvyagolskiy, A. V.The effect of the constant bias potential (Ub) supplied to the substrate upon condensation and pressure of the nitrogen atmosphere (PN) on the elemental composition, growth morphology, texture, and physical-mechanical characteristics of vacuum-arc (AlCrTiVZrNb)Nx coatings is studied. It is established that with increasing Ub from – 110V to – 200V, the axis of preferential growth of crystallites of the fcc phase from [100] to [110] changes. Such a change is accompanied by a decrease in the hardness (H) and the ratio H/E (where E is the modulus of elasticity). The conditions for the formation of the preferential orientation of the crystallites (axial texture) of vacuum-arc (AlCrTiVZrNb)Nx coatings and the influence of texture on mechanical properties are discussed. It was established that the change in PN in the range Torr basically allows to vary the degree of filling of the coating with nitrogen atoms. Based on the revealed regularities, the conditions for achieving high hardness for vacuum-arc coatings of nitrides AlCrTiVZrNb high-entropy alloy are substantiated. Because of the presence in the alloy of elements with a relatively low heat of nitride formation, in order to achieve high hardness, it is necessary to use deposition conditions with relatively low energy of bombarding atoms. The use of a low Ub = –110 V at the highest pressure Torr allows achieving an superhard state with a hardness of 44 GPa.Документ The Effect of Constant and High Voltage Pulse Bias Potentials on the Structure and Properties of Vacuum-Arc (TiVZrNbHf)Nₓ Coatings(Sumy State University, 2018) Sobol, O. V.; Postelnyk, A. A.; Mygushchenko, R. P.; Gorban, V. F.; Stolbovoy, V. A.; Zvyagolskiy, A. V.The effect of constant (Ub) and high voltage pulse (Uip) bias potentials supplied to the substrate during condensation, on the structure and properties of vacuum-arc (TiVZrN-Hf)Nх coatings has been studied. It has been determined that the number and size of the drop phase decreases with increasing Ub. The use of Uip promotes a more uniform growth in the coating volume. It is shown that due to the increase of Ub from 0 to 200 V in nitride coatings of high entropy alloys, it is possible to change the growth texture [100] to [111]. This results in increased hardness from 32 GPa to 49 GPa. The supply of high voltage potential in a pulse form leads to a relative decrease in the average size of crystallites and the formation of a bi-texture state. Conditions and mechanisms of the preferential crystallites orientation (axial texture) of vacuum arc (TiVZrNbHf)Nх coatings and texture influence on mechanical properties have been discussed.Документ The Influence of Layers Thickness on the Structure and Properties of Bilayer Multiperiod Coatings Based on Chromium Nitride and Nitrides of Transition Metals Ti and Mo(Sumy State University, 2018) Sobol, O. V.; Meylekhov, A. A.; Mygushchenko, R. P.; Postelnyk, A. A.; Tabaza, Taha A.; Al- Qawabah, Safwan M.; Gorban, V. F.; Stolbovoy, V. A.The influence of the layers thickness of bilayer multi-period coatings of the CrNx/MoNx and CrNx/TiNx systems on their phase-structural state, substructure, stress-strain state and mechanical properties was studied using methods of precision structural analysis in combination with computer simulation of implantation processes during particle deposition. It is established that a two-phase structure of CrN and-Mo2N phases of the structural type NaCl is formed in the multi-period coatings of the CrNx/MoNx system with a nanometer thickness of the layers. Because of the small difference in periods (less than 0.5 %) for Λ = 20 nm, the layers form a coherent interlayer interface. The use of small Ub – 20 V during deposition makes it possible to avoid significant mixing at interlayer (interphase) boundaries even at the smallest Λ = 10 nm. Nitride layers formed under conditions of vacuum arc deposition are under the action of compressive stresses. In the СrNх/TiNх system, because of the relatively large discrepancy between periods (more than 2.5 %), during the formation of the same structural components in the layers (CrN and TiN phases of the structural type NaCl), the epitaxial growth with period adjusting does not occur, even for the smallest Λ = 10 nm. The action of the deformation factor at the interphase boundary allows achieving an ultrahard state (with a hardness of about 50 GPa), which causes a relatively low friction coefficient. The obtained results on the formation of phase-structural states with the nanoscale thickness of layers of multi-period nitride coatings are explained from the position of minimization of surface energy and deformation energy.Документ Structural Engineering of the Multilayer Vacuum Arc Nitride Coatings Based on Ti, Cr, Mo and Zr(Sumy State University, 2017) Sobol, O. V.; Postelnyk, A. A.; Meylekhov, A. A.; Andreev, A. A.; Stolbovoy, V. A.; Gorban, V. F.The possibilities of structural engineering of multi-period vacuum-arc coatings based on nitrides of transition metals Ti, Cr, Mo, and Zr have been investigated by structural studies (X-ray diffraction and electron microscopy) in combination with measurement of hardness by indentation. The formation of phases with a cubic crystal lattice under nonequilibrium conditions under vacuum arc method of production. The supply of a negative bias potential of – 200V in mononitrides leads to the predominant formation of texture of crystallites with the [111] axis. The introduction of thin (about 10 nm) metal layers leads to a decrease in texture perfection [111] and texture formation [100]. This effect is associated with a change in the stress-strain state of nitride layers. It is determined that the composite multiperiod coatings (Me1N/Me2N)/(Me1/Me2) have a greater hardness and greater resistance compared to MeN/Me. For a multiperiod system with damping metal layers – (ZrN/CrN)/(Zr/Cr), superhard coatings with a hardness of 46 GPa were obtained.Документ А Computer Simulation of Radiation-Induced Structural Changes and Properties of Multiperiod ZrNₓ/MoNₓ System(Sumy State University, 2017) Sobol, O. V.; Meylekhov, A. A.; Bochulia, T. V.; Stolbovoy, V. A.; Gorban, V. F.; Postelnyk, A. A.; Shevchenko, S. M.; Yanchev, A. V.Influence of the period value Λ (at different negative potential Ub that supplied during deposition) on phase composition, structure, stress-strain state and hardness of multiperiod coatings ZrNₓ/MoNₓ is investigated by using complex methods of validation structural state at combined with microindentation. Formation in layers ZrNx and MoNx the phases with cubic lattice and preferred orientation of crystallites with axis [100] is established. Stress-strain state of compression with increasing Ub is amplified and reaches maximum value (– 6.7 GPa) at Λ = 20 nm and Ub – 110 V. Hardness of coating increases with decreasing Λ from 300 to 20 nm. Coatings that obtained with Λ = 20 nm and Ub – 110 V have the highest hardness 44 GPa. Relaxation of structural compressive stresses and decreasing hardness is happening at smaller Λ and larger Ub – 110 V (as a result of radiation-stimulated forming defect and mixing). Data of computer modeling of defectiveness at atomic level at bombardment of ions that accelerated in field Ub are used to explain the results.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 Influence of pressure of working atmosphere on the formation of phase-structural state and physical and mechanical properties of vacuum-arc multilayer coatings ZrN/CrN(2016) Sobol, O. V.; Andreev, A. A.; Gorban, V. F.; Stolbovoy, V. A.; Meylekhov, A. A.; Postelnyk, A. A.; Dolomanov, A. V.For multilayer coating system ZrN/CrN determined the effect of the pressure of the working atmosphere of nitrogen (Pɴ), DC (˗Us) and pulse (-Ui) negative bias potential during the deposition and the thickness of the layers in the period on the phase composition, texture, substructural characteristics and physical-mechanical properties. It is found that for Рɴ = (2.2...12)·10-4 Torr in the layers of chromium nitride formed on a lower nitrogen phase with the β-Cr2N simple hexagonal crystal lattice, and in the zirconium nitride layers are formed of a stoichiometric ZrN phase with a cubic lattice. Such a multilayer coating (layer thickness about 50 nm) at the maximum in this range Pɴ = 1.2·10-3 Torr is most solid (39 GPa) with a modulus of elasticity of 268 GPa and the ratio H/E = 0.145. At higher Pɴ, when the layers are formed phase stoichiometric composition with homogeneous crystal lattices (ZrN and СrN) hardness of the composition is not more than 33 GPa. The mechanisms of the effects observed are based on the higher barrier properties of the interphase boundary layers with different types of crystal lattices was discussed.