Перегляд за Автор "Karakurkchi, A. V."
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Документ Cobalt and manganese oxide catalytic systems on valve metals in ecotechnologies(Kyiv National University of Technologies and Design, 2017) Karakurkchi, A. V.; Sakhnenko, M. D.; Ved, M. V.; Gorohivskiy, A. S.; Galak, O.; Menshov, S.; Matykin, O.The paper discusses the preparation of cobalt and manganese oxide catalytic systems on valve metals (aluminum and titanium alloys) for eco-technologies. Oxide catalysts with d-metals based on aluminum are widely used for reduce the toxic gases emission from internal combustion engines. Catalysts based on Titania doped with transition metal oxides are also widely used in the heterogeneous and especially photo-catalysis. The higher catalytic properties in this case are demonstrated by the nano-structured oxide systems with developed surface both on aluminum and titanium alloys. From the point of view of the application convenience, better technological forms of a catalyst are the thin-film oxide coatings, formed directly on the metal substrate by the method of plasma-electrolytic oxidizing. It is considered the features of the conversion coatings formation on aluminum and titanium alloys by plasma electrolytic oxidation in alkaline electrolytes. The effect both the concentration and ratio of the electrolyte components and processing conditions on the composition and the morphology of the surface layers is studied. The difference in the plasma oxidation parameters of aluminum and titanium alloys is attributed with the various specific electric resistance of matrix metal as well as the alloying elements oxides. The oxides’ composition influence on the surface relief and their properties is investigated. The factors influenced on the catalytic properties of single and mixed oxide systems are established and the prospects for their use in technology of neutralization of toxic substances are discussed.Документ 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.Документ 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.Документ 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.Документ 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.Документ 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.Документ The electrochemical behavior of Fe³⁺ – WO₄²⁻ – Cit³⁻ and Fe³⁺ – MoO₄²⁻ – WO₄²⁻ – Cit³ systems(Украинский государственный химико-технологический университет, 2017) Yermolenko, I. Yu.; Ved, M. V.; Karakurkchi, A. V.; Sakhnenko, N. D.; Kolupayeva, Z. I.The kinetic parameters of electrochemical behavior of tungsten at the deposition of Fe–W and Fe–Mo–W alloys were determined using linear voltammetry and analyzing polarization relationships. In the presence of citrate ions the cathode process was shown to proceed with the participation of [FeHCitWO₄]⁻ clusters. An optimal concentration ratio of the components in electrolyte required for the Fe—W alloy deposition was defined as c(Fe³⁺):c(Cit³⁻):c(WO₄²⁻) = 1:1.5:0.3. The deviation from this ratio by an increase in the concentration of tungstate ions results in the formation of dimer forms W₂O₇²⁻ and [FeW₂O₇HCit]⁻ clusters; as a result the concentration of electrode active particles [FeWO₄HCit]⁻ diminishes and the cathode process is inhibited. A peculiar feature of the formation of electrolytic alloy Fe–Mo–W is a competitive reduction of molybdates and tungstates. Based on the analysis of the kinetic parameters and characteristic criteria of electrochemical reactions, we proposed the mechanism for the co-deposition of alloy containing iron with molybdenum and tungsten; this mechanism is a sequence of coupled reactions of irreversible reduction of intermediates with slow charge transfer stage and previous chemical step of the ligands release. The data of X-ray phase analysis show that the binary alloys Fe–W are solid solutions of tungsten in iron and ternary alloys Fe-Mo- W are X-ray amorphous.Документ Electrochemical deposition of Fe–Mo–W alloy coatings from citrate electrolyte(Allerton Press, 2016) Karakurkchi, A. V.; Ved, M. V.; Yermolenko, I. Yu.; Sakhnenko, N. D.Peculiarities of the electrochemical deposition of Fe–Mo–W coatings from citrate electrolyte containing iron (III) on the substrates of mild steel and gray cast iron are investigated. The effect of the salt concentration of alloying components and electrolysis modes on the quality, composition, and properties of the alloys is determined. It is shown that the alloys formed via nonstationary electrolysis exhibit a more uniform surface and lower content of impurities. The improved physical and mechanical properties as well as corrosion resistance of Fe–Mo–W coatings in comparison with the base metal can be considered as promising technologies for surface hardening and repair of worn items.Документ Electrodeposition of iron-molybdenum coatings from citrate electrolyte(Pleiades Publishing, 2014) Ved, M. V.; Sakhnenko, N. D.; Karakurkchi, A. V.; Zyubanova, S. I.Specifi c features of the electrodeposition of iron–molybdenum coatings from a citrate electrolyte based on iron(III) sulfate and sodium molybdate in dc and unipolar pulsed modes were studied. It was demonstrated that bright compact coatings with varied content of molybdenum can be produced by varying the relative concentrations of salts of the alloy-forming components and the solution pH. The current density ranges providing the high efficiency of the galvanostastic electrolysis were determined and it was shown that using the pulsed mode makes smaller the amount of nonmetallic impurities in a coating, diminishes its roughness and leads to formation of surface layers with a more uniform composition, The iron–molybdenum coatings exhibit a high corrosion resistance in corrosive media and physicomechanical properties improved as compared with the base metal, which makes it possible to recommend these coatings for protection from corrosive-mechanical disintegration and restoration of the surface of worn articles.Документ Electrodeposition of iron-molybdenum-tungsten coatings from citrate electrolytes(Pleiades Publishing, 2015) Karakurkchi, A. V.; Ved, M. V.; Sakhnenko, N. D.; Yermolenko, I. Yu.Specific features of the electrodeposition of iron–molybdenum–tungsten coatings from citrate electrolytes based on iron(III) sulfate in the dc mode and with a unipolar pulsed current were studied. It was shown that varying the relative concentrations of salts of alloy-forming metals and the solution pH makes it possible to obtain lustrous compact coatings with low porosity and various contents of high-melting components. The effect of temperature on the coating composition and current efficiency was examined. The current density ranges providing high electrolysis efficiency were found and it was demonstrated that using a pulsed current favors formation of more compositionally homogeneous surface layers at a smaller amount of adsorbed nonmetallic impurities in the coatings. The iron–molybdenum–tungsten coatings are X-ray-amorphous and have better physicomechanical properties and corrosion resistance as compared with the base, which makes it possible to recommend these coatings for application in techniques for surface reinforcement and restoration of worn-out articles.Документ Electroplating and functional properties of amorphous Fe-Mo(W) and Fe-Mo-W coatings(Институт химии растворов им. Г. А. Крестова РАН, 2015) Karakurkchi, A. V.; Ved, M. V.; Sakhnenko, N. D.; Yermolenko, I. Yu.; Zyubanova, S. I.Документ Electroplating and functional properties of Fe-Mo and Fe-Mo-W coatings(Украинский государственный химико-технологический университет, 2014) Ved, M. V.; Sakhnenko, N. D.; Karakurkchi, A. V.; Yermolenko, I. Yu.Peculiarities of electrodeposition Fe-Mo and Fe-Mo-W coatings from citrate bath containing iron (III) on substrates of mild steel and cast iron are investigated. The utilization of iron (III) compounds significantly enhanced the stability and service life of electrolyte due to elimination redox reactions involving complexing and side anodic reactions. The effect of alloying components salt concentration and electrolysis mode on the quality, composition and properties of the alloys were determined. It is shown that alloys formed in nonstationary electrolysis have a uniform surface, composition and a lower content of impurities. Increased physical and mechanical properties as well as corrosion resistance of Fe-Mo and Fe-Mo-W coatings compared with the base metal are caused by the presence of propensity for passivation alloying components as well as by amorphous structure of electroplating alloys. Indicated coatings can be considered as promising in surface hardening technologies and repair of of worn items.Документ Functional mixed cobalt and aluminum oxide coatings for environmental safety(Institute for Single Crystals, 2017) Ved, M. V.; Sakhnenko, N. D.; Karakurkchi, A. V.; Myrna, T. Yu.Principles of plasma-electrolytic oxidation of the aluminum alloys in diphosphate electrolytes are discussed. It has been established that a variation in concentration of the electrolyte components and electrolysis parameters (current density and treatment time) provides the formation of oxide coatings consisting of the basic matrix materials and the cobalt oxides of different composition and morphology that are expected to affect their functional properties. Mixed oxide coatings formed in a plasma-electrolytic mode characterized by microglobular structure with reducing the conglomerate size have an increased abrasion and wear resistance and an intense catalytic activity. Thus, there is a prospect of using such coatings in the process of burning fuel in internal combustion engines and reduce the toxicity of emissions improving fuel efficiency and environmental performance of engines and in the industrial systems of catalytic purification of exhaust gases of industrial plants and power system facilities.Документ Functional properties of multicomponent galvanic alloys of iron with molybdenum and tungsten(Institute for Single Crystals, 2015) Karakurkchi, A. V.; Ved, M. V.; Sakhnenko, N. D.; Yermolenko, I. Yu.; Zyubanova, S. I.; Kolupayeva, Z. I.Galvanic alloy coatings Fe-Mo (W) and Fe-Mo-W were deposited from citrate bath based on Fe (III) using both direct and pulsed current on substrates steel 3 and grey cast iron GC 18. It was shown that the alloying components content, their distribution on the surface, morphology and topography of the coatings are depended on the electrolysis mode. It was established that the functional properties of the binary and ternary alloys of iron (corrosion resistance, microhardness, antifriction et al.) exceed parameters of the substrate and are predetermined by the composition, structure, material and surface roughness.Документ Increasing the efficiency of intra-cylinder catalysis in diesel engines(Украинский государственный химико-технологический университет, 2017) Parsadanov, I. V.; Sakhnenko, N. D.; Ved, M. V.; Rykova, I. V.; Khyzhniak, V. A.; Karakurkchi, A. V.; Gorokhivskiy, A. S.The data of research done to systemize and choose scientific fields and search for the rational ways of an increase in the efficiency of intra-cylinder catalysis in diesel engines have been given. The use of base metal oxides and composite oxides of transition metals as the coatings for the piston combustion chamber has been substantiated. This allows us to control chemical reaction rates and reduce the formation of toxic substances. When selecting the scientific fields and rational practical ways of an increase in the efficiency of intra-cylinder catalysis in diesel engines chemical, physical and technological factors were taken into consideration. The formation of catalytic coatings based on the oxides of transition metals (Mn, Co) was provided using the plasma-electrolytic oxidizing on the Al25 alloy. These included both individual manganese and cobalt oxides and the mixed oxides of both metals. The investigation of catalytic coatings of the combustion chamber in the diesel engine piston on the basis of manganese and cobalt oxides and mixed oxides enabled the establishment of a maximum catalytic effect when cobalt oxides were used. The prototype diesel test data showed that the fuel rate in this case is decreased by 4 to 6 %, NOx emissions were reduced by 14 to 15 % and carbon oxide emissions were reduced by 20 through 25 %.Документ Mixed alumina and cobalt containing plasma electrolytic oxide coatings(IOP Publishing Ltd, 2017) Yar-Mukhamedova, G. Sh.; Ved, M. V.; Karakurkchi, A. V.; Sakhnenko, N. D.Principles of plasma electrolytic oxidation of the AL25 aluminum alloy in diphosphate alkali solutions containing cobalt(2+) cations are discussed. It has been established that a variation in the concentration of the electrolyte components provides the formation of mixed-oxide coatings consisting of the basic matrix materials and the cobalt oxides of different content. An increase in the cobalt oxide content in the coating is achieved by the variation in electrolysis current density as well as the treatment time due to both the electrochemical and thermo-chemical reactions at substrate surface and in spark region. Current density intervals that provide micro-globular surface formation and uniform cobalt distribution in the coating are determined. The composition and morphology of the surface causes high catalytic properties of synthesized materials, which confirmed the results of testing in model reaction CO and benzene oxidation as well as fuel combustion for various modes of engine operation.Документ 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.Документ 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.Документ Nanostructured catalytic cobalt containing PEO-coatings on alloy AL25(Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, 2016) Karakurkchi, A. V.; Sakhnenko, N. D.; Ved, M. V.; Gorohivskiy, A. S.Документ Nanostructured cobalt and iron electrodeposited alloys(Springer Science+Business Media, Inc., 2014) Ved, M. V.; Sakhnenko, N. D.; Glushkova, M. A.; Karakurkchi, A. V.