Журнал нано- та електронної фізики (Journal of nano- and electronic physics)
Permanent URI for this collectionhttps://devessuir.sumdu.edu.ua/handle/123456789/197
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Item 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, А.А.; 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.Item Mixing on the Boundaries of Layers of Multilayer Nanoperiod Coatings of the TiNх/ZrNх System: Simulation and Experiment(Sumy State University, 2017) Sobol, O.V.; Meylekhov, A.A.; Mygushchenko, R.P.; Postelnyk, А.А.; Sagaidashnikov, Yu.Ye.; Stolbovoy, V.A.Using the complex of methods for attestation of the structural state in combination with computer simulation and measurement of mechanical properties (hardness), the influence of the period Λ on the mixing process on the interlayer boundaries of multilayer coatings TiNх/ZrNх is studied. The formation of two phases (TiN and ZrN) with one type of crystal lattice (structural type NaCl) is identified in the layers of multiperiodic compositions TiNx/ZrNx with a period of Λ = 20 ... 300 nm. At Λ 10 nm, the formation of a solid solution (Zr, Ti)N, as well as a small volume of the TiN phase is revealed on XRD spectras. The presence of TiN component is due to the larger initial value of the layer based on titanium nitride. To explain the results obtained, the results of computer simulation of damage at the atomic level during bombardment by ions accelerated in the Ub field are used. The critical thickness of mixing (about 7 nm) in the TiNx/ZrNx system is determined upon condition that Ub = – 110 V. It is established that a decrease in the period from 300 to 20 nm leads to increase in hardness. The highest hardness of 44.8 GPa corresponds to the superhard state. It is established that the critical thickness of radiation-stimulated defect formation has a significant effect on the stress-strain state and hardness of coatings with a small Λ ≈ 10 nm. In this case, relaxation of the stress-strain compression state occurs and the hardness decreases. However, the formation of a solid solution, while retaining part of the unreacted layer of titanium nitride at Λ = 10 nm, makes it possible to obtain an ultrahigh (44.8 GPa) hardness of the coating.Item Using a bias potential in a constant and pulse modes for structural engineering vacuum arc nanocrystalline coatings of zirconium nitride(Sumy State University, 2014) Sobol’, O.V.; Andreev, A.A.; Stolbovoy, V.A.; Gorban, V.F.; Pinchuk, N.V.; Meylekhov, A.A.In order to develop the direction of "structural engineering nitride coatings" in the work conducted systematic analysis of the impact of the negative bias potential (direct and high-voltage pulse) on the structure, substructure and mechanical properties of ZrN coatings obtained by vacuum arc evaporation. Defined boundary value of (– 100 V) DC potential applied to the substrate, below which a high-voltage pulse potential (– 1200 ... – 2000 V quantity that allows to form peaks bias) makes a decisive contribution to the formation of preferred orientation of the crystallites with the [110] axis. The highest values of hardness 43 GPa are achieved at a constant potential -70 V. Supply high-voltage pulse shifts the maximum hardness in the direction of a greater value of the constant potential.