Факультет електроніки та інформаційних технологій (ЕлІТ)
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Item Experimental and theoretical studies of the physicochemical and mechanical properties of multi-layered TiN/SiC films: Temperature effects on the nanocomposite structure(Elsevier, 2018) Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Ivashchenko, V.I.; Skrynskyy, P.L.; Konarski, P.; Бондар, Олександр В`ячеславович; Бондарь, Александр Вячеславович; Bondar, Oleksandr Viacheslavovych; Zaleski, Karol; Jurga, Stefan; Coy, EmersonNanoscale multilayered TiN/SiC films are of great importance in many electronic and industrial fields. The careful control over the structure of the laminates, nanocrystalline or amorphous, is crucial for their further applicability and study. However, several limitations in their fabrication have revealed important gaps in the understanding of this system. Here, we study influence of temperature on the physico-chemical and functional properties of TiN/SiC multilayers. We will show the clear increment on hardness of the samples, while the nanocomposite structure of the layers is maintained with no increment in crystal size. We will investigate the interstitial effects and rearrangements, between the TiN/SiC phases and their role in the enhanced mechanical response. Our experiments will clearly show a change in the modulation period of the samples, pointing to interfacial reactions, diffusion of ions or crystallization of new phases. Full Investigations of the film properties were carried out using several methods of analysis: XRD, XPS, FTIR, HR-TEM and SIMS Additionally, results were combined with First Principles MD computations of TiN/SiC heterostructures.Item The effects of Cr and Si additions and deposition conditions on the structure and properties of the (Zr-Ti-Nb)N coatings(Elsevier, 2017) Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Багдасарян, Артем Анатолійович; Багдасарян, Артем Анатольевич; Bahdasarian, Artem Anatoliiovych; Кравченко, Ярослав Олегович; Кравченко, Ярослав Олегович; Kravchenko, Yaroslav Olehovych; Beresnev, V.M.; Nyemchenko, U.S.; Ivashchenko, V.I.; Shaimardanov, ZH.K.; Plotnikov, S.V.; Maksakova, O.In this study, (Zr-Ti-Nb)N, (Zr-Ti-Cr-Nb)N and (Zr-Ti-Cr-Nb-Si)N nitride coatings were obtained using a well-developed vacuum arc deposition. The systematical investigations demonstrate that the chemical composition, microstructure, and properties of the coatings intimately rely on the deposition parameters (pressure of working gas and substrate bias). Effects of Cr and Si additions on microstructure and mechanical properties of the (Zr-Ti-Nb)N coatings have been investigated using scanning electron microscopy (SEM) equipped with energy dispersive spectrum (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscope (TEM), hardness measurements and adhesion testing. First-principles band-structure calculations and Gibbs-Rosenbaum triangle representation have been used to investigate the elemental and phase compositions in nitride coatings. The multi-component (Zr-Ti-Cr-Nb-Si)N and (Zr-Ti-Nb)N coatings are found to be a simple face-centered cubic (FCC) solid solution. For the coatings without Si, the structure is mainly composed of TiN fcc phase and Cr2N trigonal modification. The hardness values were in the ranges (24–42 GPa). The (Zr-Ti-Nb)N, (Zr-Ti-Cr-Nb)N coatings provided the best adhesive strength in different conditions. The (Zr-Ti-Cr-Nb-Si)N coatings exhibited the worst adhesive strength, which may be attributed to the relative low hardness.Item Multilayer design of CrN/MoN protective coatings for enhanced hardness and toughness(Elsevier, 2017) Постольний, Богдан Олександрович; Постольный, Богдан Александрович; Postolnyi, Bohdan Oleksandrovych; Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Бондар, Олександр В`ячеславович; Бондарь, Александр Вячеславович; Bondar, Oleksandr Viacheslavovych; Beresnev, V.M.; Abadias, G.; Rebouta, L.; Araujo, J.P.We report on CrN/MoN multilayer coatings, their structure, elemental and phase composition, residual stresses, mechanical properties and their dependence on deposition conditions. The hardness and toughness were considered as main parameters for improvement of the protective properties of coatings. Multilayers with varying bilayer periods, ranging from 40 nm to 2.2 μm, were obtained by using cathodic arc physical vapour deposition (Arc-PVD) on stainless steel substrate. The elemental analysis was performed using wavelength-dispersive X-ray spectroscopy (WDS). The surface morphology and cross-sections were analysed with scanning electron microscopy (SEM). The X-ray diffraction (XRD) measurements, including grazing incidence X-ray diffraction (GIXRD), in-plane diffraction analysis and electron backscatter diffraction (EBSD), were used for microstructure characterisation. Mechanical properties of deposited films were studied by measuring hardness (H) and Young's modulus (E) with micro-indentation, H/E and H3/E2 ratios were calculated. The dependences of internal structure and, hence, mechanical properties, on layer thickness of films have been found. Significant enhancement of hardness and toughness was observed with decreasing individual layer thickness to 20 nm: H = 38–42 GPa, H/E = 0.11.Item Structural and mechanical properties of NbN and Nb-Si-N films: Experiment and molecular dynamics simulations(Elsevier, 2016) Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Бондар, Олександр В`ячеславович; Бондарь, Александр Вячеславович; Bondar, Oleksandr Viacheslavovych; Abadias, G.; Ivashchenko, V.; Sobol, O.; Jurga, S.; Coy, E.The structural and mechanical properties of NbN and Nb-Si-N films have been investigated both experimentally and theoretically, in their as-deposited and annealed states. The films were deposited using magnetron sputtering at substrate bias (UB) between 0 and 70 V. While NbN films were found to crystallize in the cubic δ-NbN structure, Nb-Si-N films with Si content of 11–13 at% consisted of a twophases nanocomposite structure where δ-NbN nanocrystals were embedded in SiNx amorphous matrix. Films deposited at UB¼0 V were highly (001)-textured. Application of substrate bias potential led to a depletion of light atoms, and caused a grain size refinement concomitantly with the increase of (111) preferred orientations in both films. The maximum hardness was 28 GPa and 32 GPa for NbN and Nb-SiN films, respectively. NbN and Nb-Si-N films deposited at UB¼ 70 V exhibited compressive stress of 3 and 4 GPa, respectively. After vacuum annealing, a decrease in the stress-free lattice parameter was observed for both films, and attributed to alteration of film composition. To obtain insights on interface properties and related mechanical and thermal stability of Nb-Si-N nanocomposite films, first principles molecular dynamics simulations of NbN/SiNx heterostructures with different structures (cubic and hexagonal) and atomic configurations were carried out. All the hexagonal heterostructures were found to be dynamically stable and weakly dependent on temperature. Calculation of the tensile strain-stress curves showed that the values of ideal tensile strength for the δ-NbN(111)- and ε-NbN(001)-based heterostructures with coherent interfaces and Si3N4–like Si2N3 interfaces were the highest with values in the range 36–65 GPa, but lower than corresponding values of bulk NbN compound. This suggests that hardness enhancement is likely due to inhibition of dislocation glide at the grain boundary rather than interfacial strengthening due to Si-N chemical bondingItem Structure and Properties of Superhard (Zr-Ti-Cr-Nb)N Coatings(Sumy State University, 2014) Постольний, Богдан Олександрович; Постольный, Богдан Александрович; Postolnyi, Bohdan Oleksandrovych; Бондар, Олександр В`ячеславович; Бондарь, Александр Вячеславович; Bondar, Oleksandr Viacheslavovych; Кравченко, Юлія Анатоліївна; Кравченко, Юлия Анатольевна; Kravchenko, Yuliia Anatoliivna; Shypylenko, A.P.; Sobol, O.V.; Beresnev, V.M.; Wegierek, P.; Smirnova, K.; Kravchenko, Ya.This work presents the results of superhard (Zr-Ti-Cr-Nb)N coatings research. Samples were fabricated by vacuum-arc deposition method (Arc-PVD). Structure, composition and properties of these coatings were studied. The study of coatings was performed using SEM, EDS and XRD. Hardness measurements and adhesion tests were provided. The coatings thickness was up to 6.2 mm. Nanocrystallites sizes ranged from 4 to 7.3 nm. Values of hardness and cohesive strength were H=43.7 GPa and LC=62.06 N respectively. The optimal conditions for coating’s deposition were found.Item Obtaining of TiN/MoN Nanocomposite Coatings and Their Research(Sumy State University, 2013) Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Бондар, Олександр В`ячеславович; Бондарь, Александр Вячеславович; Bondar, Oleksandr Viacheslavovych; Постольний, Богдан Олександрович; Постольный, Богдан Александрович; Postolnyi, Bohdan Oleksandrovych; Abadias, G.; Andreev, A.A.; Beresnev, V.M.; Chartier, P.; Sobol, O.V.; Maksakova, O.At the nanometer scale multilayer nanostructured coatings show special properties due to the depositions conditions. This paper presents results of TiN/MoN nanocomposites obtaining and their research. Multilayer coatings based on TiN/MoN were deposited using vacuum arc evaporation cathode method (CPVD). Total thickness range of obtained coatings was 2, 10, 20 and 40 nm. We used vacuum-arc device “Bulat-6” for coatings deposition. Structure and properties of multilayer coatings were analyzed using XRD (Bruker D-8 Advance) in Cu-Kα radiation, high resolution transmission electron microscopy (HRTEM system) with diffraction CFEI EO Techai F200, SEM with EDX (JEOL-7001F). Scratch tests were carried out using Rockwell-C diamond indenter (CSM Revetest Instruments) with a tip radius of 200 μm. Besides this, ball-on-plate sliding test on UMT-3MT tribometer (CETR, USA) was used for additional investigation of friction and wear. This research allowed to reveal structural and properties depending on deposition conditions of TiN/MoN multilayer coatings. The nanocomposite hardness value increases when monolayer thickness decreases. This also reduced nanograins size. Measurement of the friction coefficient demonstrates smaller values for multilayer system in comparison with TiN or MoN nanostructured coatings. Formation of a (Ti, Mo)N solid solution and nanocrystals growing were observed during annealing. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35415