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  • Ескіз
    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.
  • Ескіз
    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.
  • Ескіз
    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.
  • Ескіз
    Документ
    Structure and Properties of Vacuum Arc Single-Layer and Multiperiod Two-Layer Nitride Coatings Based on Ti(Al):Si Layers
    (Sumy State University, 2017) Beresnev, V. M.; Sobol, O. V.; Pogrebnjak, A. D.; Lytovchenko, S. V.; Stolbovoy, V. A.; Srebniuk, P. A.; Novikov, V. Ju.; Doshchechkina, I. V.; Meylehov, A. A.; Postelnyk, A. A.; Nyemchenko, U. S.; Mazylin, B. A.; Kruhlova, V. V.
    The paper provides an analysis of impact of deposition conditions on structural and phase state and thermal stability of vacuum arc coatings based on Ti(Al):Si layers. We studied single-phase single-layer coatings, and multiperiod bilayer coatings with second phase nitride interlayers of one of the following three metals: Mo, Cr or Zr. It was established that hexagonal and cubic lattices may form in the coatings when transition to the cubic lattice occurs with Al content of about 25 at. %. Presence of second nanoscale (7-8 nm) layers in bilayer multiperiod compositions, which consist of one nitride from CrNx, MoNx or ZrNx group, does not change the type of lattice in [Ti(Al):Si]Nx layers. Also, an fcc lattice with a strong or weak texture [111] forms in CrNx and ZrNx layers, while crystallites with hexagonal lattice form in MoNx layers. High-temperature annealing at 700 °С during 40 minutes leads to a significant (by 23 % or up to H 47.56 GPa) increase in microhardness of coating of the [Ti(Al)]Nx/ZrNy system due to formation of a nano-size structure with an average size of crystallites of 3.6 nm in [Ti(Al)]Nx layers, and 6.3 nm in ZrNx layers.
  • Ескіз
    Документ
    The use of plasma-based deposition with ion implantation technology to produce superhard molybdenum-based coatings in a mixed (C2H2+N2) atmosphere
    (2018) Sobol, O. V.; Andreev, A. A.; Mygushchenko, R. P.; Beresnev, V. M.; Meylekhov, A. A.; Postelnyk, A. A.; Kravchenko, S. A.; Tabaza, Taha. A.; Al-Qawabah, Safwan M.; Al-Qawabeha, Ubeidulla F.; Stolbovoy, V. A.; Serdyuk, I. V.; Kolesnikov, D. A.; Kovaleva, M. G.
    The influence of the pressure of a mixed gaseous atmosphere (80%C2H2+20%N2) and the supply of a high-voltage negative potential in a pulsed form on the elemental and phase composition, structure and physico-mechanical characteristics of the vacuum-arc molybdenum-based coatings. It is shown that in the temperature deposition range 400…550 °С as a result of plasma-chemical reactions, the maximum nitrogen atoms content in the coating does not exceed 1.5 at.%. It is found, that at the maximum pressure of РC2H2+N2= 2.3∙10-1 Pа when the γ-MoC phase is formed, an superhard state of 50.5 GPa (at a constant potential -200 V, without additional high-voltage pulse action) and 51.1 GPa (at a constant potential -200 V, with additional high-voltage pulse action) is reached.
  • Ескіз
    Документ
    The effect of the substrate potential during deposition on the structure and properties of the binanolayer multiperiod composites (TiAlSi)N/MeN (Me – Zr, Nb, Cr, Mo)
    (2018) Sobol, O. V.; Andreev, A. A.; Mygushchenko, R. P.; Stolbovoy, V. A.; Postelnyk, A. A.; Meylekhov, A. A.; Dolomanov, A. V.; Rebrova, Ye. M.
    It is proposed to use the multiperiod binanolayer composites (TiAlSi)N/MeN (Me-Zr, Nb, Cr, Mo) for controlling the structure, stress state and mechanical properties of a multi-element nitride (TiAlSi)N. The deposition of the layers was carried out by the method of vacuum-arc evaporation at different bias potentials on the substrate Ub = -110 and -200 V. It has been determined that mononitrides with a high Me-N binding energy in the binanolayer composite determine the crystallite growth in thin (nanometer) layers. The growth texture is formed in composites containing mononitrides based on transition metals with a relatively small atomic mass (Cr, Mo) at Ub = -110 V. The growth texture is formed at a larger Ub = -200 V when dealing with mononitride based on heavy metal (Zr). The greatest hardness is achieved in textured materials deposited at Ub = -200 V. This is typical both for a monolayer multi-element nitride (TiAlSi)N (hardness is 42.5 GPa) and for multiperiod nanolayer composites based on it (the highest hardness is 47.9 GPa for a composite (TiAlSi)N/ZrN).
  • Ескіз
    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.
  • Ескіз
    Документ
    Structure and mechanical properties of nitride multilayer systems on the basis of high entropy alloys and transition metals of group VI
    (2016) Nyemchenko, U. S.; Beresnev, V. M.; Sobol, O. V.; Lytovchenko, S. V.; Stolbovoy, V. A.; Novikov, V. Ju.; Meylekhov, A. A.; Postelnyk, A. A.; Kovaleva, M. G.
    The influence of technological parameters of obtaining on the possibilities of structural engineering and mechanical properties of multilayer compositions of the layers of nitrides of high entropy alloy Ti-Zr-Nb-Ta-Hf and of transition metal (Group IV) nitrides has been analysed. It is shown that with the bias potential Ub lesser than -150 V was applied to the substrate during deposition, a two-phase state with the preferred orientation of the crystallites can be reached in multilayer coatings with the thickness of the layers of 50 nm. This leads to high hardness (up to 44 GPa) and to high adhesion strength (critical load up to 125 N) as well as to low wear (with a counterbody Al ₂O₃, and with steel Ac100Cr6). High-temperature annealing (700 ⁰C) of such coatings leads to enhanced texture as a result of atomic ordering, which is accompanied by increasing of hardness up to 59 GPa. The supply of bias potential exceeding 150 V, followed by a substantial mixing at the interphase boundary results in disorientation and improves dispersion of the crystallites, reduces hardness and wear resistance. High temperature annealing of such structures leads to reduction of their mechanical properties.