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Документ Mechanical properties of galvanic metaloxide Fe-Co-MoOₓ coating(ТОВ "Твори", 2021) Tur, Yu. I.; Sakhnenko, M. D.; Ved', M. V.; Yermolenko, I. Yu.; Karakurkchi, G. V.Документ 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.Документ Сorrosion behavior of the electrolytic ternary cobalt alloys with Mo(W) and Zr in alkaline solution(Інститут загальної та неорганічної хімії ім. В. І. Вернадського, 2019) Nenastina, T. A.; Ved, M. V.; Sakhnenko, N. D.; Yermolenko, I. Yu.; Proskurina, V. A.; Volobuyev, M. M.The ternary Co–Mo–W(Zr) coatings with total content of refractory metals of 30–40 wt.%, and Co–W–Zr alloys (12–26 wt.%) are deposited from pyrophosphate-citrate electrolytes in pulse regime. The composition of the coatings as well as the surface morphology depends on the current density. The X-ray diffraction patterns reflect the amorphous-and-crystalline ternary alloys structure. Phases of α-Co, Co–Mo intermetallic compounds, and traces of metallic molybdenum were detected in the Co–Mo–Zr coatings. Phase composition of Co–Mo–W deposits differs by emergence of Co₇W₆ phase and traces of metallic tungsten, and there is no metallic W in Co–W–Zr electrolytic alloys. The corrosion behavior of ternary coatings in alkaline medium studied by EIS shows that Co–Mo–Zr alloys are characterized by highest corrosion resistance among deposited coatings due to presence of metallic molybdenum and stoichiometric ZrO₂ with both high electrical resistivity and chemical stability. The coatings Co–Mo–W and Co–Mo–Zr containing phases of Mo or W are characterized by higher corrosion resistance as compared with that without metallic molybdenum and tungsten. The cyclic voltammetry data confirm stability of ternary coatings in alkaline solution under anodic polarization. Such properties as well as the developed globular surface make materials promising for use as anodes in fuel cells in particular based on alkali electrolytes.Документ Ternary Fe–Co–Mo alloys as catalytic materials in oxidations reactions of low molecular weight alcohols(Київський національний університету технологій та дизайну, 2019) Sachanova, Yu. I.; Sakhnenko, N. D.; Ved, M. V.; Yermolenko, I. Yu.; Volobuyev, M. N.The electrocatalytic properties of ternary Fe–Co–Mo alloys synthesized from complex Fe(III) – citrate electrolytes are discussed. The relationship between the composition and surface morphology of electrolytic alloys is considered. It was found that the optimal content of molybdenum in the alloy ranges from 12 to 18 at.%. The increase in the content of this component is not possible, since it can lead to cracking and wear of the surface due to the occurrence of internal stresses. The formation of the globular structure of the alloy Fe–Co–Mo is due to the presence of a refractory metal. The resulting alloys exhibit electrocatalytic activity in the oxidation reactions of methanol and ethanol, as evidenced by the high values of currents in the anodic and cathodic regions of cyclic voltammetric dependencies with maximum values at 0.56 V and 0.6 V, respectively. The course of adsorption of methanol and ethanol on the surface of the alloy Fe–Co–Mo has been established.Документ Composition, Morphology, and Topography of Galvanic Coatings Fe–Co–W and Fe–Co–Mo(2017) Yermolenko, I. Yu.; Ved, M. V.; Sakhnenko, N. D.; Sachanova, Yu. I.Ternary coatings Fe-Co-W with an iron content of 40–55 at.%, cobalt 39–44 at.%, and tungsten 4–12 at.% and Fe-Co-Mo with an iron content of 40–55 at.%, cobalt 39–44 at.%, and tungsten 4–12 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 2.5–3.5 μm. The surface of Fe-Co-Mo is characterized by parts of a globular structure with an average conglomerate size of 0.3–0.5 μm and singly located cone-shaped hills with a base diameter of 3 μm. 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 0.2–1.75 μm.Документ Cobalt based coatings as catalysts for methanol oxidation(Науково-технологічний комплекс "Інститут монокристалів", 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.Документ 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.Документ Galvanic ternary Fe−Co−W coatings: structure, composition and magnetic properties(Науково-технологічний комплекс "Інститут монокристалів", 2018) Yermolenko, I. Yu.; Ved, M. V.; Sakhnenko, N. D.; Fomina, L. P.; Shipkova, I. G.Principles of Fe–Co–W alloys electrodeposition from complex Fe (III) based citrate electrolytes are discussed. The effect of both current density and pulse on/off time on the quality, composition and surface morphology of the electrolytic alloys were determined. The application of pulsed electrolysis provides increasing ungsten content up to 13 at.%, at current efficiency of 70-75 %. Globular surface 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 coherent-scattering region size of the amorphous part is 2-8 nm. Magnetic characteristics of amorphous Fe–Co–W coatings were measured in dependence of deposition ime. The conclusion was made that the content of magnetic phase in upper layers of coating is greater than in the bottom ones due to decreasing W atom concentration.Документ Internal stresses and magnetic properties of Fe-Co electrolytic coatings(Науково-технологічний комплекс "Інститут монокристалів", 2017) Proskurina, V. O.; Yermolenko, I. Yu.; Zyubanova, S. I.; Shipkova, I. G.; Avramenko, B. A.; Sachanova, Yu. I.Consideration was given to the effect of electrolysis parameters on the composition and the properties of electrolytic iron-cobalt film coatings obtained from citrate electrolytes. The interconnection between the film composition and the film thickness with its internal stresses and magnetic properties has been studied. It was established that Fe60Co40 alloys show the lowest level of internal stresses for the saturation induction of 1.8 to 2.1 Tl.Документ Influence of alloying elements on corrosion-mechanic properties of multi-component electrolytic alloys(2018) Ved, M. V.; Yermolenko, I. Yu.; Nenastina, T. O.; Ziubanova, SvitlanaДосліджено кількісний і фазовий склад покривів тернарними сплавами Fe-Co-Mo(W) та Co-Mo-W(Zr), осаджених з моно і білігандних електролітів постійним та імпульсним струмом. Результати рентгеноструктурного аналізу свідчать про аморфно-кристалічну структуру сплавів, наявність фаз інтерметалідів Fe7Мо, Fe7Co, FeCo, Co7W6, Fe7W6, разом із α-Fe та Fe3C, причому розміри кристалітів аморфної частини знаходяться в інтервалі 7–8 нм. Методом сканівної електронної спектроскопії, атомно-силової мікроскопії і рентгеноспектрального мікроаналізу встановлено вплив природи та вмісту тугоплавких і рідкісних металів на морфологію, шорсткість поверхні покривів, а також розміри кристалітів і агломератів. Методом поляризаційного опору встановлено, що корозійна стійкість покривів на 1,3–2,0 порядки величини вища за параметри матеріалу підкладки. Визначено залежність швидкості корозійного процесу у хлоридвмісному середовищі від складу електролітичних сплавів. За даними спектроскопії електродного імпедансу встановлено еквівалентні схеми заміщення, їх параметри і доведено тотожність показників корозійного опору, одержаних різними методами. Проаналізовано вплив складу і морфології поверхні на мікротвердість електролітичних сплавів. Показано, що за фізико-механічними характеристиками тернарні покриви Fe-Co-Mo(W), Co-Mo-W(Zr) не поступаються електролітичним покривам твердим хромом.
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