Публікації співробітників (ВІТВ НТУ "ХПІ")

Постійне посилання колекціїhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/21692

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Nanocomposite electrolytic coatings based on cobalt alloys with refractory metals: obtaining, properties, application
(Kazakh University IP "Center for Operational Printing", 2022) Yar-Mukhamedova, G. Sh.; Nenastina, T. A.; Ved, M. V.; Sakhnenko, N. D.; Karakurkchi, A. V.
Modern electrochemical technologies for surface treatment of titanium alloys to create protective, antifriction, dielectric, and catalytically active materials are considered. The physicochemical fundamentals of the processes of plasma-electro-lytic formation of conversion and composite electrolytic coatings are highlighted. Separate stages of electrode reactions, regularities of the influence of electrolyte components, and electrolysis parameters on the composition, structure, and morphology of synthesized materials are examined in detail. Considerable attention is paid to improving the synthesis of multicomponent alloys and composites based on cobalt from aggregative stable and stable electrolyte solutions, and flexible control of the composition and functional properties of materials is an urgent scientific and technical problem, the solution of which is the presented study. The monograph summarizes the results of the project AP 08855457, "Development of an innovative technology for producing nanocrystalline composite coatings for fuel cell electrodes and hydrogen energy". This research has been funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan. The monograph is designed for specialists in the field of chemical technology, as well as teachers, graduate students, and students of higher educational institutions.
Corrosion properties of galvanic Fe–Mo(W), Fe–Mo–W coatings
(Науково-технологічний комплекс "Інститут монокристалів", 2019) Ved, M. V.; Sakhnenko, N. D.; Karakurkchi, A. V.; Pershina, K. D.; Yermolenko, I. Yu.
The methods of analysis of polarization dependences, the electrode impedance spectroscopy and gravimetry were used for the investigation of the corrosion properties of galvanic binary Fe–Mo(W) and ternary Fe–Mo–W coatings in the media of a different acidity. It was shown that the corrosion rate of Fe–Mo–W and Fe–Mo(W) alloys is decreased with an increase in the pH of the solutions and with the enrichment of the alloys by doping refractory components. The dependence of the control of corrosion process on the composition of electrolytic alloys has been specified. It was established that the corrosion resistance of binary alloys is 1.1 to 1.5 orders of magnitude higher in comparison with the parameters of substrate materials, in particular the mild steel. The corrosion resistance indices for the coatings applied using the ternary Fe–Mo–W alloys substantially prevail over those for mild steel, individual metals and binary Fe–Mo and Fe–W coatings. The corrosion resistance of Fe–Mo–W system is equal to 8300 Ohm·cm² and it is conditioned by the formation of the two-component layer film consisting of molybdenum oxides and tungsten oxides. Using the data of gravimetric investigations we constructed the diagrams "the corrosion depth index kh, mm/year – the composition" for the Fe–Mo–W system that allow us to define the metal content ratio for Fe–Mo(W), Fe–Mo–W alloys in order to provide an appropriate corrosion resistance depending on service conditions.
Effect of Electrodeposition Parameters on the Composition and Surface Topography of Nanostructured Coatings by Tungsten with Iron and Cobalt
(Institute of Combustion Problems, Kazakhstan, 2020) Yar-Mukhamedova, G. Sh.; Ved, M. V.; Yermolenko, I. Yu.; Sakhnenko, N. D.; Karakurkchi, A. V.; Kemelzhanova, A.
The electrodeposition of binary and ternary coatings Fe-W and Fe-Co-W from mono ligand citrate electrolyte has been investigated. The Fe-Co-W coatings were formed from electrolytes, which composition differs in the ratio of the concentrations of the alloying components and the ligand content. The investigation results indicate a competitive reduction of iron, cobalt and tungsten, the nature of which depends both on the ratio of electrolyte components, and electrolysis parameters. The effect of both current density amplitude and pulse on off time on quality, composition and surface morphology of the galvanic alloys was determined. Coatings deposited on a direct current with a density of more than 6.5 A/dm², crack and peel off from the substrate due to the inclusion of Fe (III) compounds containing hydroxide anions. The use of non-stationary electrolysis allows us to extend the working range of current density to 8.0 A/dm² and form electrolytic coatings of sufficient quality with significant current efficiency and the content of the refractory component. The presence of the Co₇W₆, Fe₇W₆, α-Fe, and Fe3C phases detected in the Fe-Co-W deposits reflects the competition between the alloying metals reducing from hetero-nuclear complexes. The surface of binary and ternary coatings is characterized by the presence of spherical agglomerates and is more developed in comparison with steel substrate. The parameters Ra and Rq for electrolytic alloy Fe-W are of 0.1, for Fe-Co-W are 0.3, which exceeds the performance of a polished steel substrate (Ra = 0.007 and Rq = 0.010). These properties prospect such alloys as a multifunctional layer are associated with structural features, surface morphology, and phase composition.
Composition and morphology of Fe-Co-Mo electrolytic alloys
(Інститут хімії поверхні ім. О. О. Чуйка, 2016) Sachanova, Yu. I.; Yermolenko, I. Yu.; Sakhnenko, N. D.; Ved, M. V.
Nanoscale oxide PEO-coatings forming from pyrophosphate electrolytes
(Ivan Franko National University, 2016) Sakhnenko, N. D.; Karakurkchi, A. V.; Ved, M. V.; Gorohivskiy, A. S.; Galak, A. V.
Effect of Doping Metals on the Structure of PEO Coatings on Titanium
(2018) Sakhnenko, N. D.; Ved, M. V.; Karakurkchi, A. V.
The structure and properties of the oxide films formed on titanium alloys by means of plasma-electrolytic oxidizing in alkali electrolytes based on pyrophosphates, borates, or acetates of alkali metals with the addition of dopants’ oxides or oxoanions of varying composition have been studied. Anodic polarization in the spark discharge (microarc) mode at application of interelectrode potential 90 to 160V has been used to obtain mixed-oxide systems TiOₓ·WOᵧ, TiOₓ ·MoOᵧ, TiOₓ ·ZrO₂, and TiOₓ ·V₂O₅. The possibility to obtain the oxide layers containing the alloying elements by the modification of the composition of electrolytes has been stated. The chemical and phase composition as well as the topography, the microstructure, and the grain size of the formed layers depend on the applied current, interelectrode voltage, and the layer chemical composition. The effect of formed films composition on the resistance of titanium to corrosion has been discussed. Catalytic activity of mixed-oxide systems was determined in the model reaction of methyl orange dye MO photodestruction.
Research of the peculiarities of plasma-electrolytic treatment of AK12M2MgN piston alloy with formation of ceramic-like coatings
(Полтавская государственная аграрная академия, 2018) Karakurkchi, A. V.; Sakhnenko, N. D.; Ved, M. V.; Parsadanov, I. V.
Досліджено особливості плазмово-електролітичної обробки (ПЕО) поршневого силуміну АК12М2МгН у лужних електролітах з формуванням допованих манганом та кобальтом керамікоподібних покривів. Показано, що морфологія та склад оксидних покривів залежать від типу використовуваного електроліту. Визначено технологічні параметри ПЕО-обробки поршневого силуміну для формування рівномірних покривів із високим вмістом допантів. Запропоновані системи можуть знайти застосування в технологіях внутрішньоциліндрового каталізу з метою зниження токсичності газових викидів двигунів та підвищення їх паливної економічності.
Synthesis of catalytic cobalt-containing coatings on alloy AL25 surface by plasma electrolytic oxidation
(Інститут хімії поверхні ім. О. О. Чуйка НАН України, 2017) Ved, M. V.; Karakurkchi, A. V.; Sakhnenko, N. D.; Gorohivskiy, A. S.
The study aims at the investigation of the influence of electrolyte composition and plasma electrolytic oxidation modes on the composition and morphology of a mixed aluminum and cobalt oxides at the AL25 alloy. Composition, morphology and surface roughness of the oxide systems are examined by scanning electron microscopy, X-ray analysis and atomicforce microscopy. Mixed oxide coatings Al₂O₃·CoOₓ formed from the diphosphate electrolytes at various concentration ratio diphosphate/cobalt sulfate contain cobalt of 8-30 at. % (in terms of metal) in the matrix of alumina. Plasma electrolytic oxidation in a two-stage mode of the incident power provided formation of strongly adhered coatings characterized by non-stoichiometry ratio of cobalt and oxygen as well aslow content of silicon in deposits. Obtained mixed oxide systems have developed surface with alternating the spheroid and torus-shaped structures which is associated with a large number of catalytic sites. They exhibit catalyticbehavior in the model reactions of CO conversion to CO₂ and benzene oxidation not inferior to the contacts with noble metals. The coatings Al₂O₃·CoOₓ contribute to fuel economy and improve the environmental performance of the internal combustion engine thus can be recommended for use in the neutralization of gas emissions systems and as coatings for pistons of combustion chamber.
Effect of doping metals on the structure of PEO coatings on Ti
(Publishing House SME "Burlaka", 2017) Karakurkchi, A. V.; Sakhnenko, N. D.; Ved, M. V.; Mayba, M. V.
The effect of the electrolysis regime on the composition and morphology of Fe–Co–Mo(W) coatings
(Publishing House SME "Burlaka", 2017) Yermolenko, I. Yu.; Ved, M. V.; Sakhnenko, N. D.; Karakurkchi, A. V.