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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 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 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 70–75%. 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 Co₇W₆, Fe₇W₆ along with α-Fe and Fe₃C. The crystallite size of the amorphous part is near 7–8 nm. Corrosion resistance of the coatings is 1.3–2.0 orders of magnitude higher than the substrate parameters as follows from data of polarization resistance method and electrode impedance spectroscopy.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 Surface analysis of Fe-Co-Mo electrolytic coatings(IOP Publishing Ltd, 2017) Yar-Mukhamedova, G. Sh.; Sakhnenko, N. D.; Ved, M. V.; Yermolenko, I. Yu.; Zyubanova, S. I.Coatings Fe-Co-Mo with a composition of 47 at.% iron, 28 at.% Cobalt and 25 at.% Molybdenum were deposited from citrate electrolyte using pulse electrolysis mode. Scanning electron and atomic force microscopy have established the surface morphology and topography. It was identified the parts with a globular structure which have an average size of 0.2-0.5μm and singly located sharp grains. Within the same scan area sites with developed surface were detected the topography of which is identical to the crystal structure of cobalt with the crystallites size of 0.2–1.75μm. The parameters Ra and Rq for parts with different morphology as well as average characteristics of coatings demonstrated the low roughness of the surface. It is found that the coercive force of Fe-Co-Mo films is 7-10 Oe, which allow us to classify the Fe-Co-Mo coatings as soft magnetic materials.