Публікації співробітників (ВІТВ НТУ "ХПІ")

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

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The Role of Electrolysis Regimes in the Formation of Metal and Metal Oxide Coatings from Complex Citrate Electrolytes
(Київський національний університет технологій та дизайну, 2020) Sachanova, Yu. I.; Sakhnenko, N. D.; Ved', M. V.; Yermolenko, I. Yu.; Pospelov, A. P.
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.
Determining features of application of functional electrochemical coatings in technologies of surface treatment
(Технологический центр, 2019) Karakurkchi, A.; Sakhnenko, M.; Ved, M.; Yermolenko, I. Yu.; Pavlenko, S.; Yevsieiev, V.; Pavlov, Y.; Yemanov, V.
Approaches to the use of electrochemical coatings in surface treatment technologies are analyzed. It is shown that directed surface modification allows expanding the functional properties of the treated material, in particular, increasing the strength, wear resistance, corrosion resistance, catalytic activity. The method for treating non-alloy steel and cast irons by forming thin-film coatings of ternary alloys of iron and cobalt with molybdenum and tungsten is proposed. It is shown that the incorporation of refractory metals up to 37 at. % into the surface layer leads to a change in the phase structure of the coating. This is found to provide an increase in wear resistance by 40 %, microhardness by 2.5–3.5 times, as well as a decrease in friction coefficient by 3–4 times in comparison with the substrate material. The resulting materials can be used for hardening and protection of surfaces in various industries. To modify the surface of piston silumins, it is proposed to use the method of plasma electrolytic oxidizing with the formation of ceramic-like coatings. It is shown that in the galvanostatic mode, from alkaline electrolyte solutions containing manganese and cobalt salts, it is possible to obtain uniform, dense, highly adhesive to the base metal, oxide coatings, doped with catalytic components whose content varies within 25–35 at. %. It is shown that the morphology and phase structure of the surface layers changes with the incorporation of dopant metals. The formed coatings have a high degree of surface development, which is a prerequisite for enhancing their functional properties. The proposed approach is used to modify the surface of the KamAZ-740 piston. It is found that the use of ceramic-like coatings of the engine piston leads to a decrease in hourly fuel consumption and amount of toxic substances with exhaust gases, which makes them promising for use in in-cylinder catalysis.
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.
Research into composition and properties of the Ni–Fe electrolytic alloy
(Технологический центр, 2017) Sknar, Y.; Sknar, I.; Cheremysinova, A.; Yermolenko, I. Yu.; Karakurkchi, A.; Mizin, V.; Proskurina, V. O.; Sachanova, Y.
Встановлено вплив умов елек-тролізу на склад сплаву Ni–Fe, електроосадженого із метилсульфонатного електроліту. Показано, що натрій сахаринат істотно не впливає на склад сплаву при густині струму вище 2 А/дм². Встановлено, що натрій сахаринат сприяє підвищенню мікротвердості і зниженню внутрішніх напружень і коерцитивної сили покриттів. Проаналізовано залежність досліджених властивостей сплаву Ni–Fe від структури осаду.
Research into influence of the electrolysis modes on the composition of galvanic Fe-Co-Mo coatings
(Технологический центр, 2017) Yermolenko, I. Yu.; Ved, M.; Karakurkchi, A.; Proskurina, V. O.; Sknar, I.; Kozlov, Ya.; Sverdlikovska, O.; Sigunov, O.
Досліджено вплив енергетичних (густина струму і) і часових (тривалість імпульсу tі і паузи tn, співвідношення tі/tn) параметрів електролізу на склад та морфологію покриттів Fe-Co-Mo. Встановлено, що підвищення тривалості імпульсу сприяє збагаченню сплаву молібденом тим більше, чим вище густина струму. Показано, що зі збільшенням густини струму структура поверхні покриттів змінюється від дрібнозернистої до глобулярної.
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.
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.
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.