Публікації співробітників (ВІТВ НТУ "ХПІ")

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

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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.
Плазмово-електролітичний синтез гетерооксидних покривів на високолегованих сплавах алюмінію
(Фізико-механічний інститут ім. Г. В. Карпенка НАН України, 2018) Сахненко, Микола Дмитрович; Каракуркчі, Ганна Володимирівна; Ведь, Марина Віталіївна; Ярошок, Тамара Петрівна; Руднєва, Світлана Іванівна; Горохівський, Андрій Сергійович
The scientific principles of control of the composition of heteroxide coatings on aluminum alloys with transition metals are substantiated by varying the formulation of electrolytes, modes and parametersof synthesis by the method of plasma-electrolytic oxidation (PEO). The results of the research aimed to establish a patterns of electrochemical synthesis coatings both mono- and doped oxides in the modes of PEO. The influence of external conditions and internal factors on the structure, element composition, morphology and operating properties of the obtained materials is analyzed. It was established that the composition, surfacemorphology and functional properties of oxide coatings on aluminum alloys depend on the composition of electrolytes andoxidation mode. It is proved the possibility obtaining multicomponent oxide coatings with high adhesionin one-stageusing PEO. It was established that the inclusion of cobalt on the oxide coatings on the aluminumalloy АК12М2МgN leads to formation of a mosaic three–dimensional surface structure, in which the PEO coating contain maximum of cobalt. It is found that mixed oxides coatings systems Al/Al₂O₃, CoOᵧ and Al/Al₂O₃, MnOᵧ, CoOᵧ as promising materials for heterogeneous catalysis can be prepared by electrochemical technology on metal substrates in PEO mode. According to the spectroscopy of the electrode impedance, equivalent schemes of substitution of hetero-oxide systems in different acidity medium have been established. Parameters of multicomponent oxide coatings have been determined, based on which the deep and current corrosion rates have been calculated. It was noted increase of their corrosion resistance in comparison with Al/Al₂O₃ caused by homogenization of the surface layer and the formation of smooth micro globular structure. The system Al/Al₂O₃, MnOᵧ, CoOᵧ identified the highest catalytic properties with the total content of the dopants to 6 at.% in a bench test of the diesel engine in the forced modes reduces fuel consumption.
Электрокаталитическое окисление метанола на тернарных сплавах кобальта
(НТУ "ХПИ", 2018) Ненастина, Татьяна Александровна; Ведь, Марина Витальевна; Сахненко, Николай Дмитриевич; Проскурина, Валерия Олеговна; Ермоленко, Ирина Юрьевна
Электролитические покрытия тернарными сплавами Co-Mo-W и Co-Mo-Zr, нанесенные из комплексных пирофосфатно-цитратных электролитов, отличаются равномерно развитой поверхностью, рельеф и степень развития которой благоприятны для реализации каталитических процессов. Электрокаталитическое окисление метанола, как энергоемкого реагента топливных элементов, на электродах их указанных сплавов характеризуется наличием одной волны с четко выраженным предельным током. Активность электродов с тернарными покрытиями в реакции окисления метанола значительно выше, чем платины, причем для сплава Co-Mo-Zr высота пика в 2-2.5 раза выше, чем для Со-Mo-W. Повышенная каталитическая активность покрытий обусловлена как высокой степенью развития поверхности, так и синергетическим эффектом сплавообразующих металлов. Совокупность кинетических критериев указывает на необратимое электрокаталитическое окисление метанола на исследованных сплавах в режиме смешанной кинетики через стадию адсорбции реактанта. Тернарные покрытия обладают высокой коррозионной стойкостью в щелочных средах и по значению глубинного показателя коррозии относятся к весьма стойким. Высокие каталитическая активность и коррозионная стойкость сплавов Co-Mo-W и Co-Mo-Zr позволяют рассматривать их как перспективные материалы электрохимической энергетики, в том числе для проточных редокс аккумуляторов и топливных элементов.
Функциональные свойства гетерооксидных ситем на основе TiO₂
(НТУ "ХПИ", 2018) Каракуркчи, Анна Владимировна; Ведь, Марина Витальевна; Сахненко, Николай Дмитриевич; Яр-Мухамедова, Гульмира Шариповна
Плазменно-электролитическим оксидированием сплавов титана в щелочных электролитах с введеним соединений тугоплавких металлов получены гетерооксидные покрытия микроглобулярной морфологи с высокой адгезией. В роли допантов использованы диспергированные в электролите наноразмерные оксиды ванадия, циркония и молибдена, а также растворы вольфрамата натрия, что позволило формировать гетерооксидные покрытия как из коллоидных, так и истинных растворов. Установлено влияние допантов на параметры процесса и виявлены интервалы напряжений, соответствующих микродуговому режиму. По результатам сканирующей электронной и атомно-силовой микроскопии показано, что управление химическим составом покрытий, топографией поверхности и размером зерен можно варьированием концентрации электролита и плотности тока плазменно-электролитического оксидирования. Установлено, что сформованные оксидные слои имеют высокую стойкость к абразивному зносу и существенно повышают коррозионную стойкость титана в хлоридсодержащих средах вследствие инкорпорации тугоплавких компонентов и сгладживанию рельефа поверхности.
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.
Synthesis and functional properties of mixed titanium and cobalt oxides
(Institute for Single Crystals, 2017) Ved, M. V.; Sakhnenko, N. D.; Karakurkchi, A. V.; Mayba, M. V.; Galak, A. V.
Peculiarities of plasma-electrolytic oxidation of the aluminum alloys in diphosphate electrolytes are discussed. It is shown that PEO parameters depend on the composition and concentration of the components of the working solutions. The mechanism of cobalt oxides incorporation into the composition of surface layers is proposed. It has been established that the oxidation of titanium in citrate-diphosphate electrolytes promotes the formation of mixed oxide layers TiOx·CoOy. The obtained mixed oxide systems have a developed microporous globular-toroidal surface and are characterized by a complex of enhanced functional properties - corrosion and abrasion resistance, catalytic activity in the carbon (II) oxide conversion reaction.
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.
Functional Properties of Fe−Mo and Fe−Mo−W Galvanic Alloys
(Springer, Heidelberg, Allemagne, 2016) Ved, M. V.; Sakhnenko, N. D.; Karakurkchi, G. V.; Yermolenko, I. Yu.; Fomina, L. P.
The influence of the modes of electrodeposition on the morphology, topography, and structure of the galvanic alloys of iron with molybdenum and tungsten is discussed. It is shown that the increase in the corrosion resistance of Fe–Mo and Fe–Mo–W coatings in acid and neutral chloride-containing media is caused both by the elevation of their passivating ability caused by the process of alloying components and by the formation of globular surfaces with homogeneous chemical composition. The microhardnesses of Fe–Mo and Fe–Mo–W galvanic alloys prove to be 2–3 times higher than the microhardnesses of the substrates made of low-alloy steel, which can be explained by the formation of amorphous structures. The results of investigations and tribological tests show that it is reasonable to apply the coatings of double and triple iron alloys in order to reduce wear in friction couples and to increase the corrosion resistance and mechanical strength of the surfaces, which makes them promising for the repair and restoration technologies.
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.
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.