Публікації співробітників (ВІТВ НТУ "ХПІ")

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

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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.
Research on the improvement of mixed titania and Co(Mn) oxide nano-composite coatings
(2018) Yar-Mukhamedova, G.; Ved, M.; Karakurkchi, A.; Sakhnenko, N.; Atchibayev, R.
The structure and the properties of the oxide films formed on titanium in the diphosphate based electrolytes by means of plasma electrolytic oxidizing at direct current density of 2-2.5 A·dm⁻² have been studied. Oxide layers of different composition and content of alloying elements were obtained by modification of electrolytes and variation in current density. The interelectrode voltage during PEO, chemical and phase composition, topography and microstructure of the formed layers depend on the electrolyte composition and applied current density. The spark-discharge regime was shown to be reached at inter-electrode voltage 100 to 130 V depending on the composition of electrolyte. The effect of chemical composition and surface morphology formed mixed oxide films on the corrosion resistance and catalytic activity has been discussed.
Application of oxide-metallic catalysts on valve metals for ecological catalysis
(Технологический центр, 2017) Karakurkchi, A.; Sakhnenko, M.; Ved, M.; Galak, A.; Petrukhin, S.
Запропоновано спосіб одержання оксидно-металевих каталізаторів методом одностадійного плазмово-електролітичного оксидування вентильних металів для знешкодження токсидів природного та техногенного походження. Обґрунтовано застосування оксидів мангану та кобальту як легуючих компонентів. Встановлено, що одержані оксидні покриви характеризуються високою каталітичною активністю в модельних реакціях конверсії токсичних компонентів, зокрема відпрацьованих газів двигунів внутрішнього згоряння.
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.
A study of synthesis and properties of manganese-containing oxide coatings on alloy VT1-0
(Технологический центр, 2016) Sakhnenko, M.; Ved, M.; Karakurkchi, A.; Galak, A.
Досліджено вплив складу манганвмісних пірофосфатних електролітів і режимів плазмово-електролітичного оксидування на процеси формування і будову оксидних покривів на сплаві титану ВТ1-0. Показано шляхи керування топографією поверхні, хімічним і фазовим складом покривів, а також інкорпоруванням у них оксидів мангану. Встановлено, що синтезовані оксидні шари характеризуються підвищеною стійкістю до абразивного зносу і високою каталітичної активністю у реакціях окиснення монооксиду вуглецю.
Morphology and Properties of Coatings Obtained by Plasma-Electrolytic Oxidation of Titanium Alloys in Pyrophosphate Electrolytes
(Pleiades Publishing, 2017) Sakhnenko, M.; Ved, M.; Karakurkchi, A.
By means of scanning electron microscopy, atomic-force microscopy, X-ray fluorescence analysis, and X-ray spectral microanalysis it was shown that, under plasma-electrolytic oxidation (PEO) of titanium alloys in pyrophosphate electrolytes, well-adhered oxide coatings with microglobular morphology result. It was demonstrated that the chemical and phase composition of the coatings, as well as the surface topography and grain size, can be controlled by changing the concentration of a pyrophosphate electrolyte and a PEO current density. It was established that the resulting oxide layer is highly resistant to abrasive wear and enhances the titanium corrosion resistance in model media (Ringer’s solution) substantially, which suggests that the coatings are promising for use in biological applications.
Study of the influence of oxidizing parameters on the composition and morphology of Al₂O₃·CoOₓ coatings on AL25 alloy
(Технологический центр, 2018) Karakurkchi, A.; Sakhnenko, M.; Ved, M.
The influence of operating parameters of plasma-electrolytic oxidation in diphosphate cobalt-containing electrolyte on the process of formation of oxide coatings on alumosilicon alloy AL25 (GOST 1583) was studied. It was shown that inclusion of cobalt into the composition of surface oxide layers leads to a change of morphology and topography of the surface. Variation of current density and PEO time allows flexible control of the process of incorporation of the catalytic component into the matrix of oxide of basic metal. It was shown that at an increase in oxidation time, cobalt content in the surface oxide layer increases. The rational mode of plasma-electrolytic treatment of piston alloy in diphosphate electrolyte for obtaining oxide coatings, enriched with cobalt, was substantiated. It is advisable to perform formation of PEO-coatings on AL25 with developed globular-mosaic surface, maximum cobalt content, with minimizing impurities in the range of current densities of 3–5 A/dm² within 20–40 min. The obtained cobalt-containing oxide coatings can be used in the air and water purification systems, specifically, for intracylinder catalysis of gas emissions of internal combustion engines.
Study into formation of cobalt-containing peo-coatings on AK12M2MgN from a pyrophosphate electrolyte
(Технологический центр, 2017) Karakurkchi, A.; Sakhnenko, M.; Ved, M.; Horokhivskyi, A.; Galak, A.
We studied the process of formation of cobalt-containing oxide coatings using plasma-electrolytic oxidizing of the aluminum alloy AK12M2MgN in pyrophosphate electrolytes. It was established that the use of given type solutions contributes the homogenization of silumin surface and creates preconditions for the dopants incorporation to the growing oxide coating. It is shown that PEO parameters depend on the concentration ratio of cobalt sulfate and potassium pyrophosphate in a working solution. Based on the results of experimental study, we demonstrated the ways to control the structure and surface morphology of cobalt-containing PEO coatings through the variation in the concentrations of electrolyte components. The composition of a pyrophosphate electrolyte for the formation of oxide PEO-coatings with a high cobalt content and developed surface morphology is substantiated. It is noted that the obtained oxide coatings could be used in catalytic reactions in order to decompose natural and technogenic toxicants.
Iron binary and ternary coatings with molybdenum and tungsten
(Elsevier Inc., 2016) Ved, M.; Sakhnenko, N. D.; Karakurkchi, A.; Yermolenko, I. Yu.; Yar-Mukhamedova, G.
Electrodeposition of Fe-Mo-W and Fe-Mo layers from a citrate solution containing iron(III) on steel and iron substrates is compared. The utilization of iron(III) compounds significantly improved the electrolyte stability eliminating side anodic redox reactions. The influence of concentration ratios and electrodeposition mode on quality, chemical composition, and functional properties of the alloys is determined. It has been found that alloys deposited in pulse mode have more uniform surface morphology and chemical composition and contain less impurities. Improvement in physical and mechanical properties as well as corrosion resistance of Fe-Mo and Fe-Mo-W deposits when compared with main alloy forming metals is driven by alloying components chemical passivity as well as by alloys amorphous structure. Indicated deposits can be considered promising materials in surface hardening technologies and repair of worn out items.