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Item Effect of Bias Voltage and Nitrogen Pressure on the Structure and Properties of Vacuum-Arc (Mo + Ti6%Si)N Coatings(Pleiades Publishing, Ltd, 2017) Beresnev, V.M.; Sobol, O.V.; Litovchenko, S.V.; Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Srebnyuk, P.A.; Novikov, V.Yu.; Kolesnisov, D.A.; Meilekhov, A.A.; Postel’nik, A.A.; Nemchenko, U.S.Effect of deposition conditions in reactive nitrogen atmosphere on the growth morphology, phase composition, structure, and mechanical characteristics (microhardness) of vacuum-arc multilayer coatings obtained using evaporation of the (Ti6%Si) and Mo cathodes is studied with the aid of raster electron micros- copy, energy-dispersive elemental microanalysis, and microindentation. It is demonstrated that nitrogen atoms are redistributed to the region of the strongest nitride-forming element (Ti) in relatively thin layers (about 7 nm) consisting of substances with substantially different heats of formation (−336 kJ/mol for TiN and −34 kJ/mol for MoN). Such a process leads to lamination with the formation of nitride TiN and metal Mo (weaker nitride-forming element). Nitrogen–metal bonds are saturated in the layers of strong nitride- forming elements Ti(Si) when the nitrogen pressure increases from 6 × 10–4 to 5 × 10–3 Torr in the conden- sation procedure. Thus, the compound is filled with nitrogen to the stoichiometric composition and, then, the second system of layers based on molybdenum is saturated with nitrogen with the formation of the γ- Mo2N phase. An increase in bias potential USP from –100 to –200 V stimulates mixing in thin layers with the formation of the (Ti, Si, Mo)N solid solution and leads to a decrease in microhardness from 37 to 32 GPa.Item Radiation Resistance of high-entropy nanostructured (Ti, Hf, Zr, V, Nb)N coatings(Pleiades Publishing, Ltd., 2015) Komarov, F.F.; Konstantinov, S.V.; Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr DmytrovychThe influence of high-fluence ion irradiation of nanostructured (Ti, Hf, Zr, V, Nb)N coatings is revealed for the first time. The energy of irradiating helium ions is equal to 500 keV, and their fluence falls into the interval 5 × 1016–3 × 1017 ions/cm2 . The performance of the coatings in a nuclear reactor is simulated by conducting post-irradiation thermal annealing at 773 K for 15 min. The elemental composition, structure, morphology, and strength properties of the (Ti, Hf, Zr, V, Nb)N coatings are studied before and after irradiation. No considerable structural and phase modifications in the coatings are found after irradiation, except for the fact that crystallites in the coatings drastically reduce in size to less than 10 nm. Nor does the atomic composition of the coatings change. It is shown that the microhardness of the coatings depends on the fluence of irradiating ions nonlinearly. It can be argued that the (Ti, Hf, Zr, V, Nb)N coatings are radiationresistant and hence promising for claddings of fuel elements in nuclear reactors.Item Structure and Properties of (Zr–Ti–Cr–Nb)N Multielement Superhard Coatings(Allerton Press, Inc., 2015) Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Постольний, Богдан Олександрович; Постольный, Богдан Александрович; Postolnyi, Bohdan Oleksandrovych; Кравченко, Ярослав Олегович; Кравченко, Ярослав Олегович; Kravchenko, Yaroslav Olehovych; Shipilenko, A.P.; Sobol’, O.V.; Beresnev, V.M.; Kuz’menko, A.P.Structure and properties of (Zr–Ti–Cr–Nb)N multicomponent nanostructured coatings fabricated by a vacuumarc deposition have been investigated. It has been found that the coatings thickness attained 6.2 μm, hardness and indentation load that is responsible for the stress exceeding cohesion strength of coatings were H = 43.7 GPa and Lc = 62.06 N, respectively. In coatings structures have been identified that consist of three interstitial phases having cubic, hexagonal, and tetragonal lattices. The nanocrystallites sizes were from 4 to 7.3 nm. The results of the SEM, TEM, EDS, and XRD analysis have been also considered.Item Influence of the phase and elemental compositions and defect structure on the physicomechanical properties and tribotechnical characteristics of nanostructural Ti-Hf-Si-N coatings(Springer, 2014) Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Каверін, Михайло Валерійович; Каверин, Михаил Валерьевич; Kaverin, Mykhailo Valeriiovych; Beresnev, V.M.A new approach to preparing superhard nanostructural Ti–Hf–Si–N coatings with high physico mechanical performance is developed and tested. Samples with Ti–Hf–Si–N nanocoatings obtained under different deposition conditions were investigated using nuclear physical analysis methods, namely, Ruther- ford backscattering, energy dispersive X ray analysis, secondary ion mass spectrometry, and the slow positron beam method, as well as by conducting X ray diffraction analysis and microhardness measurements and testing the tribotechnical performance of the films. It is found that the grain size varies from 3.9 to 10.0 nm depending on the bias applied to the substrate and the residual pressure in the chamber during nanocoating deposition. It is shown that the microhardness varies considerably (from 37.4 to 48.6 ± 1.2 GPa) according to the percentage and number of phases, grain size, and material transfer along nanograin boundaries and interfaces. In tribological tests of the Ti–Hf–Si–N nanocoatings, the mechanism of cohesive and adhesive fracture changes and the friction coefficient may vary from 0.46 to 0.15.Item Влияние параметров осаждения нитридов высокоэнтропийных сплавов (TiZrHfVNb)N на их структуру, состав, механические и трибологические свойства(Институт сверхтвердых материалов им. В. Н. Бакуля, 2013) Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Бондар, Олександр В`ячеславович; Бондарь, Александр Вячеславович; Bondar, Oleksandr Viacheslavovych; Береснев, В.М.; Abadias, G.; Chartier, P.; Takeda, Y.; Oyoshi, Y.; Соболь, О.В.; Андреев, А.А.; Мукушев, Б.А.; Якущенко, И.В.Методами растрової електронної та атомно-силової мікроскопії, енер- годисперсійного аналізу, аналізу Резерфордівського оберненого розсіювання іонів, рентгнодифракційного аналізу, вимірюванням мікротвердості та трибологічними випробуванями досліджено нітриди високоентропійних сплавів (TiZrHfVNb)N, отримані за допомогою вакуумно-дугового випарування катоду. Виявлено вплив параметрів осадження на структуру, морфологію поверхні, розподіл елементів, механічні та трибологічні властивості досліджуваних покриттів. При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/34184Item Formation of perspective composite coatings by ion-beam assisted deposition(Polish Academy of Sciences Institute of Physics, 2013) Комаров, Ф.Ф.; Пилько, В.В.; Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Карват, С.; Karvat, C.; Kiszczak, К.; Козак, С.TiAlN, TiSiN, and TiCrN composite layers were deposited by magnetron sputtering and sliding angle ion beam sputtering of the inner surface of hollow truncated cones of different compositions. The composition of both type coatings and component depth distributions were studied by the Rutherford backscattering spectrometry. The structural and phase analyses of the deposited films were performed by transmission electron microscopy and diffraction. Microhardness, wear resistance and friction coefficient of the coatings were also measured and discussed in the relationship with the structure and composition. Microhardness tests showed that the registered data varied in the range 10 to 50 GPa, depending on composition and concentration of components. The best wear protection results from the magnetron deposited Ti-Al-N systems in a narrow range of component concentrations. A minimal friction coefficient was revealed for the magnetron sputtered layers. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/33941Item Влияние двойной имплантации ионов на физико-химические и механические свойства поверхностных слоев сплавов ВТ-6, ВТ-22(Изд-во "Наука", 2010) Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Дуб, С.Н.; Маликов, А.В.; Ердыбаева, Н.К.; Кирик, Г.В.; Гриценко, Б.П.; Левинтант, Н.; Русаков, В.С.; Углов, В.В.; Братушка, Сергій Миколайович; Братушка, Сергей Николаевич; Bratushka, Serhii MykolaiovychВ работе представлены новые результаты по исследованию структуры и физико механических свойств приповерхностных слоев титановых сплавов ВТ 6 и ВТ 22 после имплантации ионов (W,Mo) и последующего термического отжига при температуре 550°С в течение двух часов. Использовались методы: резерфордовского обратного рассеяния ионов (РОР) гелия и протонов,растровой электронной микроскопии (РЭМ) с микроанализом (EDS, WDS), индуцированного протонами (ионами) индуцированного рентгеновского излучения, рентгенофазового анализа в скользящей (0.5°) геометрии, мессбауэровской спектроскопии. Проведены исследования нанотвердости и модуля упругости, износа при трении цилиндра по плоскости. Обнаружено увеличение твердости почти в два раза, уменьшение износа и повышение усталостной прочности за счет формирования мелкодисперсных (наноразмерных) фаз нитридов, карбонитридов и интерметаллидов. New results of investigation of structure, physicochemical and mechanical properties of surface layers of titanium alloys due to implantation of W or Mo ions and followed heat annealing at 550°C during 2 h were presented.Item Физико-химические и триботехнические свойства железа, оплавленного импульсной плазменной струей(2007) Братушка, Сергій Миколайович; Братушка, Сергей Николаевич; Bratushka, Serhii Mykolaiovych; Погребняк, Олександр Дмитрович; Погребняк, Александр Дмитриевич; Pohrebniak, Oleksandr Dmytrovych; Тюрин, Ю.Н.Представлені результати досліджень физико-хімічних і тріботехнічних властивостей зразків Fe, оплавлених і легованих за допомогою плазмового струменя. Мікротвердість оплавлених зразків зросла в 2,5 разу в порівнянні з початковими, а їх зношування при терті стало в 2 рази нижче від початкового. Приповерхневий шар заліза легований елементами, що містяться в електроді: W, Co, Cu. Разом з а-Fe в поверхневому шарі утворюються мілкодисперсні карбіди Fe6W6C, а також, можливо, W6Co6C. Після випробувань на зношування на глибині 15 мкм від поверхні тертя легованого Fe виявлено до 1,2 ат.W. Result of studies, which were performed using iron samples (0.08 zhf) treated by a pulsed plasma jet. A hard alloy WC–Co, which additionally doped the sample surface at the moment of melting of a surface iron layer, was used as an eroding electrode. In the surface layer we found Fe6W6C carbides of small dimension ranges and Fe, Co and Co6W6C. W concentration in the surface (micro- and nanocrystal) layer reached 8.5 at. Co concentration changed from 16 to 32 at. We also found that friction wear resistance increased be a factor of three, nano- and microhardness was minimum 2.0 GPa to 7.9 GPa.