ΠΠ΅ΡΠ΅Π³Π»ΡΠ΄ Π·Π° ΠΠ²ΡΠΎΡ "Ved, M. V."
ΠΠ°ΡΠ°Π· ΠΏΠΎΠΊΠ°Π·ΡΡΠΌΠΎ 1 - 20 Π· 52
Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡΠ² Π½Π° ΡΡΠΎΡΡΠ½ΡΡ
ΠΠ°Π»Π°ΡΡΡΠ²Π°Π½Π½Ρ ΡΠΎΡΡΡΠ²Π°Π½Π½Ρ
ΠΠΎΠΊΡΠΌΠ΅Π½Ρ AFM surface analysis of FeβCoβMo electrolytic coatings(ΠΠ½ΡΡΠΈΡΡΡ Ρ ΡΠΌΡΡ ΠΏΠΎΠ²Π΅ΡΡ Π½Ρ ΡΠΌ. Π. Π. Π§ΡΠΉΠΊΠ° ΠΠΠ Π£ΠΊΡΠ°ΡΠ½ΠΈ, 2017) Yermolenko, I. Yu.; Ved, M. V.; Sakhnenko, N. D.; Zubanova, S. I.; Tychyna, O. N.The study aims at the investigation of the morphology and topography of the ternary FeβCoβMo electrolytic coatings. Compositions and morphology of the alloys are examined by scanning electron microscopy and X-ray analysis. Both topography and surface roughness are studied by an atomic force microscopy AFM using a NTβ206 microscope. The FeβCoβMo coatings with an iron content of 47 at.%, cobalt 28 at.% and molybdenum 25 at.% are deposited on mild steel substrate by pulse electrolysis mode from citrate bath with the ratio of concentrations Ρ(FeΒ³βΊ):Ρ(CoΒ²βΊ):Ρ(MoOβΒ²β») = 2.5:3:1. Atomic force microscope analysis topography of the coatings FeβCoβMo at the scanning area 39.9Γ39.9 ΞΌm show that their surface is more developed compared with the substrate material. Moreover the AFM analysis of the coatings morphology and surface topography indicates the parts with a globular structure with an average conglomerates size of 0.2-0.5 ΞΌm and singly located sharp grains. Within the same scan area, sites with a developed surface are detected the topography of which is identical to the crystal structure of cobalt with the crystallite size in the range of 0.2-1.75 ΞΌm. The parameters Ra and Rq for parts with different morphology as well as average characteristics of coatings demonstrated the low roughness of the surface. Electrolytic deposits FeβCoβMo can be attributed to 8-9-th class of roughness. The study tested the magnetic behavior of FeβCoβMo coatings. The coercive force of 7-10 Oe confirms the soft magnetic properties of materials which in combination with high microhardness open prospects for usage of FeβCoβMo systems in the production of magnetic head elements for recording and reproducing information.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ ANN simulation of nanocomposites Fe(Co)-W corrosion resistance(Π₯Π°ΡΠΊΡΠ²ΡΡΠΊΠΈΠΉ Π½Π°ΡΡΠΎΠ½Π°Π»ΡΠ½ΠΈΠΉ ΡΠ½ΡΠ²Π΅ΡΡΠΈΡΠ΅Ρ ΠΌΡΡΡΠΊΠΎΠ³ΠΎ Π³ΠΎΡΠΏΠΎΠ΄Π°ΡΡΡΠ²Π° ΡΠΌΠ΅Π½Ρ Π. Π. ΠΠ΅ΠΊΠ΅ΡΠΎΠ²Π°, 2019) Ved, M. V.; Sakhnenko, N. D.; Nenastina, T. A.; Volobuyev, M. N.; Yar-Muhamedova, G. H.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ Catalytic properties of binary and ternary alloys based on silver(ΠΠ°ΡΠΊΠΎΠ²ΠΎ-ΡΠ΅Ρ Π½ΠΎΠ»ΠΎΠ³ΡΡΠ½ΠΈΠΉ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡ Β«ΠΠ½ΡΡΠΈΡΡΡ ΠΌΠΎΠ½ΠΎΠΊΡΠΈΡΡΠ°Π»ΡΠ²Β» ΠΠ°ΡΡΠΎΠ½Π°Π»ΡΠ½ΠΎΡ Π°ΠΊΠ°Π΄Π΅ΠΌΡΡ Π½Π°ΡΠΊ Π£ΠΊΡΠ°ΡΠ½ΠΈ, 2013) Ved, M. V.; Glushkova, M. A.; Sakhnenko, N. D.The correlation between the morphology, composition and catalytic properties of silver-cobalt alloys has been shown. The galvanic Ag-Co alloy is established as synergetic ones, and the values obtained for the exchange current density of the model hydrogen evolution reaction are similar to platinum. The catalytic activity testing results of binary (Ag-Co) and ternary (Ag-Co-Zr, Ag-Co-Bi) alloys in the carbon monoxide oxidation to carbon dioxide were analyzed.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ Characterization and photocatalytic activity of Ti/TinOmβZrxOy coatings for azo-dye degradation(Institute for Single Crystals, 2014) Sakhnenko, N. D.; Ved, M. V.; Bykanova, V. V.Anodic oxidation of VT1-0 titanium and E-125 zirconium alloy in aqueous electrolyte solutions based on HβSOβ and KβPβOβ was used to obtain oxide coatings composed of Zr/ZrOx Ti/TiOy, and mixed oxide systems Ti/TinOm ZrxOy. It was shown that, depending on the electrolyte pH, the films contain up 0.17 to 2.1 % wt. of zirconium. Catalytic activity of the synthesized coatings in the oxidation reaction of methyl orange azo dye under UV irradiation was established. The process rate constants and synergy factors for the mixed systems were calculated.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ The classes of inorganic substances(2020) Ved, M. V.; Korohodska, A. M.; Proskurina, V. O.The classes of inorganic substances are the fundamental material in the course of general and inorganic chemistry studying. The classification of substances facilitates the study and systematizes the whole variety of inorganic compounds in nature. Knowing the structural features of the chemical compounds classes, it is possible to characterize the properties of their individual representatives. The purpose of the work is to help students fill the missing knowledge and fully master the presented material. The nomenclature, production and chemical properties of the main classes of inorganic compounds (oxides, bases, acids and salts) are considered.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ 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 oxidesβ 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.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ Cobalt based coatings as catalysts for methanol oxidation(ΠΠ°ΡΠΊΠΎΠ²ΠΎ-ΡΠ΅Ρ Π½ΠΎΠ»ΠΎΠ³ΡΡΠ½ΠΈΠΉ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡ "ΠΠ½ΡΡΠΈΡΡΡ ΠΌΠΎΠ½ΠΎΠΊΡΠΈΡΡΠ°Π»ΡΠ²", 2020) Nenastina, T. A.; Ved, M. V.; Sakhnenko, N. D.; Yermolenko, I. Yu.; Volobuyev, M.; Proskurina, V. O.The cobalt based coatings with refractory metals (Mo, W, Zr) were deposited from pyrophosphate-citrate electrolytes in a pulsed mode. It has been shown that, with increasing current density, Co-Mo-W and Co-W-ZrO2 alloys are enriched in tungsten, grain sizes decrease, but a network of cracks appears on the surface of the Co-Mo-W coating. In the Co-Mo-ZrO2 coating, with increasing current density, the zirconium content increases due to molybdenum, and the surface is the most fractured and small-globular. The surface roughness parameters for Co-Mo-ZrO2 are one order of magnitude higher than those for Co-Mo-W. Cyclic voltammograms show that the Co-Mo-ZrO2 deposits are characterized by the highest stability under anodic polarization due to the inclusion of molybdenum and zirconium(IV) oxide in their composition. The kinetics of the methanol anodic oxidation on electrodes coated with cobalt alloys was studied, and the participation of intermediate metal oxides in oxygen transport was revealed. A significant increase in the anode current peak indicates a higher electro-catalytic activity of the zirconium-containing coatings among the studied alloys.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ Composition and Corrosion Behavior of Iron-Cobalt-Tungsten(Institute of Combustion Problems, Kazakhstan, 2018) Ved, M. V.; Sakhnenko, N. D.; Yermolenko, I. Yu.; Yar-Mukhamedova, G. Sh.; Atchibayev, R.Principles of three component Iron-Cobalt-Tungsten alloys electrodeposition from complex Fe (III) based citrate electrolytes are discussed. It is shown, that deposition of ternary alloys proceeds through competitive reduction of cobalt and tungsten with iron. With increasing ligand concentration coatings are enriched with a refractory component; however, increasing current density favors a reverse trend. The effect of both current density and pulse on/off time on the quality, content of alloying metals and surface topography of electrolytic coatings were determined. The application of pulsed electrolysis provides increasing tungsten content up to 13 at.%, at current efficiency of 70β75%. Globular relief of Fe-Co-W coatings is caused by refractory metals incorporation, and crystalline and amorphous parts of structure are visualized by X-ray spectroscopy, including inter-metallic phases CoβWβ, FeβWβ along with Ξ±-Fe and FeβC. The crystallite size of the amorphous part is near 7β8 nm. Corrosion resistance of the coatings is 1.3β2.0 orders of magnitude higher than the substrate parameters as follows from data of polarization resistance method and electrode impedance spectroscopy.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ Composition and morphology of Fe-Co-Mo electrolytic alloys(ΠΠ½ΡΡΠΈΡΡΡ Ρ ΡΠΌΡΡ ΠΏΠΎΠ²Π΅ΡΡ Π½Ρ ΡΠΌ. Π. Π. Π§ΡΠΉΠΊΠ°, 2016) Sachanova, Yu. I.; Yermolenko, I. Yu.; Sakhnenko, N. D.; Ved, M. V.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ Composition, Morphology, and Topography of Galvanic Coatings FeβCoβW and FeβCoβMo(2017) Yermolenko, I. Yu.; Ved, M. V.; Sakhnenko, N. D.; Sachanova, Yu. I.Ternary coatings Fe-Co-W with an iron content of 40β55 at.%, cobalt 39β44 at.%, and tungsten 4β12 at.% and Fe-Co-Mo with an iron content of 40β55 at.%, cobalt 39β44 at.%, and tungsten 4β12 at.% were obtained by galvanostatic and pulse electrolysis on the mild steel substrate from iron(III) citrate-based electrolyte. The influence of electrolysis mode and parameters on composition of deposited alloys was studied. The competing reduction of iron and tungsten in Fe-Co-W coatings as well as the competitive deposition of iron and cobalt in Fe-Co-Mo coatings at various current densities were defined. Simultaneously, the alloy enrichment with molybdenum is more marked at a pulse mode. Atomic force microscope analysis of the Fe-Co-W alloy coating morphology and surface topography indicates their globular structure with spherical grains in the range of 2.5β3.5 ΞΌm. The surface of Fe-Co-Mo is characterized by parts of a globular structure with an average conglomerate size of 0.3β0.5 ΞΌm and singly located cone-shaped hills with a base diameter of 3 ΞΌm. Sites with a developed surface were detected within the same scan area which topography is identical to the crystal lattice of cobalt with the crystalline conglomerate sizes in the range of 0.2β1.75 ΞΌm.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ Corrosion properties of galvanic FeβMo(W), FeβMoβW coatings(ΠΠ°ΡΠΊΠΎΠ²ΠΎ-ΡΠ΅Ρ Π½ΠΎΠ»ΠΎΠ³ΡΡΠ½ΠΈΠΉ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡ "ΠΠ½ΡΡΠΈΡΡΡ ΠΌΠΎΠ½ΠΎΠΊΡΠΈΡΡΠ°Π»ΡΠ²", 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 FeβMo(W) and ternary FeβMoβW coatings in the media of a different acidity. It was shown that the corrosion rate of FeβMoβW and FeβMo(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 FeβMoβW alloys substantially prevail over those for mild steel, individual metals and binary FeβMo and FeβW coatings. The corrosion resistance of FeβMoβW system is equal to 8300 OhmΒ·cmΒ² 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 β the composition" for the FeβMoβW system that allow us to define the metal content ratio for FeβMo(W), FeβMoβW alloys in order to provide an appropriate corrosion resistance depending on service conditions.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ Corrosion-electrochemical properties of cobalt-molybdenum-zirconium deposits(Kyiv National University of Technologies and Design, 2016) Koziar, M. A.; Slavkova, M. A.; Sakhnenko, N. D.; Ved, M. V.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ 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.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ 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 dopantsβ 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 TiOβΒ·WOᡧ, TiOβ Β·MoOᡧ, TiOβ Β·ZrOβ, and TiOβ Β·VβOβ . 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.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ 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/dmΒ², 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/dmΒ² and form electrolytic coatings of sufficient quality with significant current efficiency and the content of the refractory component. The presence of the CoβWβ, FeβWβ, Ξ±-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.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ The effect of the electrolysis regime on the composition and morphology of FeβCoβMo(W) coatings(Publishing House SME "Burlaka", 2017) Yermolenko, I. Yu.; Ved, M. V.; Sakhnenko, N. D.; Karakurkchi, A. V.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ The electrochemical behavior of FeΒ³βΊ β WOβΒ²β» β CitΒ³β» and FeΒ³βΊ β MoOβΒ²β» β WOβΒ²β» β CitΒ³ systems(Π£ΠΊΡΠ°ΠΈΠ½ΡΠΊΠΈΠΉ Π³ΠΎΡΡΠ΄Π°ΡΡΡΠ²Π΅Π½Π½ΡΠΉ Ρ ΠΈΠΌΠΈΠΊΠΎ-ΡΠ΅Ρ Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΠ½ΠΈΠ²Π΅ΡΡΠΈΡΠ΅Ρ, 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 FeβW and FeβMoβW 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 [FeHCitWOβ]β» clusters. An optimal concentration ratio of the components in electrolyte required for the FeβW alloy deposition was defined as c(FeΒ³βΊ):c(CitΒ³β»):c(WOβΒ²β») = 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 WβOβΒ²β» and [FeWβOβHCit]β» clusters; as a result the concentration of electrode active particles [FeWOβHCit]β» diminishes and the cathode process is inhibited. A peculiar feature of the formation of electrolytic alloy FeβMoβW 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 FeβW are solid solutions of tungsten in iron and ternary alloys Fe-Mo- W are X-ray amorphous.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ Electrochemical deposition of FeβMoβW 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 FeβMoβW 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 FeβMoβW coatings in comparison with the base metal can be considered as promising technologies for surface hardening and repair of worn items.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ Electrochemical synthesis of nickel-based composite materials modified with nanosized aluminum oxide(Pleiades Publishing, 2015) Sakhnenko, N. D.; Ovcharenko, O. O.; Ved, M. V.Electrochemical synthesis of nickel-based composite coatings and foil reinforced with nanosized aluminum oxide is reported. Ni-AlβOβ composites with different content of the modifying phase were prepared by chemical dispersion of aluminum oxide using the βfrom above downβ principle. The influence of the aluminum oxide concentration in the electrolyte on the physicomechanical properties of the reinforced foil was determined. Incorporation of reinforcing phase particles into the metal matrix leads to a decrease in the grain size and enhances by a factor of 2β6 the strength characteristics of the coatings and foil. The topography of the surface and the cross section profile of the composites were examined, and the influence of these characteristics on the properties of the materials was determined.ΠΠΎΠΊΡΠΌΠ΅Π½Ρ Electrodeposited cobalt alloys as materials for energy technology(Cambridge University Press, 2013) Glushkova, M. A.; Bairachna, T.; Ved, M. V.; Sakhnenko, N. D.The influence of electrodeposition parameters on chemical composition, morphology and functional properties of such binary cobalt alloys as CoAg, CoW, and CoFe has been investigated. The alloys are shown to possess catalytic properties. Catalytic actuvity was preliminary estimated in the electrolytic hydrogen evolution reaction and tested by CO to CO2 conversion during the catalytic benzene oxidation.