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The work is presented by the V. I. Vernad­skii Institute of General and Inorganic Chemi­stry of the National Academy of Sciences of Ukraine for the State Prize of Ukraine in the field of science and technology. A new paradigm of the processes of electrochemical synthesis of functional materials has been created on the basis of the proposed theory of discharge-ionization of electrochemically active complexes and the laws of correlation between the functional properties of coatings and the fundamental characteristics and parameters of electrochemical kinetics. New approaches of surface engineering to the electrochemical synthesis and processing of materials that are capable of operating under extreme thermomechanical conditions under the simultaneous action of an aggressive medium have been developed. Innovatively promising technologies have been proposed for the formation of nanomaterials of new generation based on superalloys, metal oxide composites, photosensitive hetero- and nanostructures, electrically conductive polymers and their composites, etc. The main research directions in this work concern electrochemistry, both directly the me­thod for the synthesis of new materials and the study and design of the electrochemical pro­perties of materials / coatings / nanoparticles that cannot be obtained by other methods. The aim of the work was to develop the theoretical foundations of directed synthesis and to create a wide range of new competitive materials and systems on the basis of establishing the structural and functional patterns of their electrochemi­cal formation. А number of novel compe­titive electrochemical materials (electrode and electrolyte materials for electrochemical po­wer sources and supercapacitors, electro- and photocatalysts, sorption and optical materials, functional coatings, etc.) have been created as a result of the performed research. These materials are used in various fields of science and technology, namely, for alternative po­wer ge­neration, electrochemical power sources, nano- and microelectronics, electrochromic systems, electrocatalysis, ecosensorics, electro­chemical synthesis of commercial products, photoelectrochemical systems, corrosion protection. The number of publications: 700, including 30 monographs (7 of them published abroad) and 39 chapters in collective monographs (30 of them published abroad), 36 textbooks (manuals), and 500 articles (350 of them published in foreign periodicals). The total number of refe­rences to the publications of the authors/h-index/i10-index (regarding the whole work) according to the databases is, respectively: Web of Science, 1856/21/52; Scopus, 2185/22/71; Google Scholar, 4903/33/148. The novelty and competitiveness of the technical solutions are protected by 33 valid patents (7 patents of Kazakhstan, China, USA). Eight doctoral dissertations (DSc) and 47 candidate's dissertations (PhD theses) on this subject matter have been defended.

We study the corrosion behaviors of electrolytic composite coatings based on ternary cobalt alloys under different conditions and analyze the distribution of metals over the thickness of the coating and the parameters of their surface roughness. The accumulated results show that, in alkaline and neutral media, the corrosion potentials shift in the negative direction as compared with the potentials measured in an acid media but corrosion resistance does not undergo any significant changes. This can be explained by the fact that tungsten and molybdenum oxides formed on the surface are unstable in alkaline media. In view of the fact that in neutral solutions, the subsurface layer becomes alkaline due to the reduction of oxygen and chlorides provoke local fractures of the protective film, we can assert that alloying metals exert a synergistic effect on the rate of corrosion of the composites. According to the computed values of the depth indicator of corrosion rate, the analyzed coatings can be referred to the group of highly resistant, whereas the composites based on Co64Mo33Zr3 alloy in neutral and alkaline media belong to the group of very stable materials. This opens wide possibilities for their application as protective coatings on metals in aggressive media.

The processes of plasma-electrolytic formation of heteroxide coatings on titanium alloys for the photocatalytic disintegration of natural and technogenic toxicants are studied. Synthesis of coatings was carried out from aqueous diphosphate solutions in the galvanostatic mode. For a quantitative description of photocatalytic reactions, reaction rate constants were calculated from the linearized dependences lnCt/C0, where Ct is the current concentration of the azodye and C0 is the initial concentration of the reactant. The surface morphology of the coatings was studied by atomic force microscopy and visualized the results by reconstructing the relief in the form of 2D and 3D topographic maps. The morphological features of titanium (IV) oxide coatings and heteroxide composites containing zinc and / or copper oxides are analyzed. It has been shown that the specific surface remains an effective factor in controlling the photocatalytic activity of coatings; therefore, the establishment of the morphology of heteroxide composites, as well as methods for controlling this parameter of the target product, is an invariable component of a systematic study of such materials when establishing their functional properties. It is established that, in comparison with titanium oxide coatings, whose surface layers are characterized by toroidal mesostructures, heteroxide compositions have a more developed surface, which positively affects their functional properties. Subsequent heat treatment also has the same effect on coating properties. The rate constants of the photocatalytic decomposition of the methyl orange azodye, determined under similar conditions, were used to rank coatings of various compositions according to their functional properties. Thus, for the reaction on the surface of titanium oxide, the rate constant is 1.56∙10–3 min–1, while for the heterooxide layer TiO2·ZnO it increases to 5.8∙10–3 min–1. The coating of TiO2·ZnO is the most catalytically active, although the TiO2·ZnO·CuO system also accelerates the decomposition process with a degree of degradation of 25% for 60 minutes, further, the efficiency of the catalyst decreases.

The possibility of electrosynthesis and control of the composition of galvanic coatings by alloys based on metals of the iron group with refractory metals, in particular molybdenum, from a complex citrate electrolyte by varying the electrolysis modes has been proved. It has been established that coatings with a high oxygen content are formed by direct current, namely, more molybdenum oxides are fixed in these coatings in comparison with coatings used in unipolar pulsed electrolysis. In the latter case, the oxygen content on the protrusions and depressions is much lower and is respectively 21 at.% And 25 at.%. It was shown that during pulsed electrolysis, the content of the metal form of molybdenum is higher as a result of the reduction of molybdenum oxides with intermediate oxidation levels by hydrogen ad-atoms, which are formed in the partial cathodic reaction. The reduction occurs due to the spillover effect, the implementation of which is most effective during a current interruption. The formation of the oxide phase of inclusions directly during electrolysis without introducing it into the electrolyte as a second phase is justified. Depending on the completeness of this process, conditions are created for the formation of a metal coating from ternary alloys or metal oxide composites, the second phase of which consists of molybdenum oxides of an intermediate oxidation state, that is, a process is formed directly in the electrode. According to the results of atomic force microscopy, it was found that coatings synthesized in the galvanostatic mode can be classified as composite electrolytic materials, and the cathode deposit obtained as a result of unsteady electrolysis can be attributed to metal. The doped coatings obtained in a pulsed mode are characterized by lower porosity. The surface free energy for metal and composite coatings was calculated, the values of which are 127.74 mJ/m2 and 118.10 mJ/m2. When testing the electrocatalytic activity of Fe-Co-Mo ternary alloys in the reaction of electrolytic hydrogen evolution, high values of the hydrogen exchange current density were obtained both for metal and composite coatings.

possibility of electrosynthesis and control of the composition and surface morphology of the composite electrolytic coatings of cobalt with refractory metals by varying the pulse current density has been proved. Composites deposited on copper substrate from biligand citrate-pyrophosphate electrolytes at 4 A/dm 2 are distinguished by a developed surface and a more uniform distribution of components on the surface, increased tungsten content, almost 5 times higher than coatings deposited at 10 A/dm 2 , and a half reduction in oxygen percentage (up to 5.5%). This is explained by the inhibition of the hydrogen gas evolution reaction and the participation of hydrogen ad-atoms in the chemical reduction of intermediate tungsten oxides to metal when polarization is interrupted. Coatings obtained using pulsed current can be considered as composites of the composition Co-W-ZrO 2 , in which the oxide phase is formed directly in the electrode process as an intermediate for the incomplete reduction of tungstates. The topography of the films is characterized by the presence of grains of elliptical and spherical shape with crystallite sizes of 80 – 180 nm. On the main surface there are protrusions (large grains) with a diameter of 1 – 3 microns. The fractal dimension of the surface is 2.77, which indicates the 3D crystal growth mechanism during coating formation. According to the surface roughness parameters Ra and Rq, coatings belong to the 9th roughness class. By phase composition, composites are predominantly amorphous materials, which include nanocrystalline cobalt and intermetallic compounds Co3W and Zr 3 Co. Due to the quantitative and phase composition, surface morphology and fractality, the microhardness and corrosion resistance of Co-W-ZrO 2 systems deposited at a current density of 4 А/dm 2 are 20% higher than the coatings obtained at 10 A/dm 2 , and 3 times higher than the corresponding characteristics of the substrate.

We propose efficient regimes of the formation of mixed-oxide conversion coatings by plasma-electrolytic oxidation (PEO) of aluminum alloys in pyrophosphate and alkaline electrolytes. It is shown that the variations of the concentrations of electrolyte components and the parameters of PEO (current density and the duration of treatment) lead to the appearance of oxide coatings formed by the material of the metal matrix and oxides of transition metals of various compositions and morphologies, which definitely affect their functional properties. Mixed oxide coatings formed as a result of PEO are characterized by microglobular structures, small sizes of conglomerates, and elevated microhardness. Moreover, they are corrosion and wear resistant. In view of the microglobular structure of the surface and the composition of Al Al2O3·MnOx and Al Al2O3·CoOx oxide coatings, we can expect that the obtained materials may exhibit catalytic activity in the redox reactions with participation of oxygen and, in particular, in the working processes running in internal-combustion engines.

The process of mixed oxide coatings formation on a high-silicon aluminum alloy in a cobalt-containing pyrophosphate electrolyte by the plasma-electrolytic oxidation (PEO) method is studied. It was shown that AL25 chemical composition heterogeneity causes the consumption of a part of the anode current to homogenize the treated surface, which is reflected in minimizing the content of doping components at the initial processing stage. It was established that the growth of mixed oxides Al2O3·CoxOy relative mass is a function of time with a maximum at 55 minutes. The chemical, phase composition and surface morphology of the formed oxide layer depend on the oxidation time. The catalytic component content in the surface oxides varies from 0.2 to 23.3 at.% with an increase in processing time of 10 to 60 minutes. Maximum cobalt incorporation into the oxide layer occurs at PEO of 35–50 minutes, while the silicon content in the surface layers does not exceed 2 at.%, which is favorable for the catalytic properties. The cobalt oxide, preferably Co3O4, incorporation in the alumina α-Al2O3 matrix is visualized by the blue-violet color steroidal surface structures in the sites of micro-arc discharges. The alumina cobalt oxide mixture layers are characterized by a developed micro-globular surface which consists of spheroid conglomerate with an average size of 1–2 microns. There are some amorphous phases in the structure of mixed oxides due to non-equilibrium PEO conditions. The set of detected factors is a prerequisite for the high catalytic properties of oxide coatings. A promising field of Al2O3·CoxOy systems application is intra-cylinder catalysis in internal combustion engines.

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.

The patterns of changes in the morphology and strength characteristics of oxide coatings for the aluminum alloy AD-0 under conditions of different duration of plasma-electrolytic oxidation in a 1.0 M alkaline electrolyte K 4 P 2 O 7 solution have been established. The changing of the molding voltage has a classic view – four stages, the first three (pre-spark, spark, microarc) contributes to the gradual hardening of the alloy surface, and at the fourth (arc) stage microhardness decreases and becomes instable, as well as delamination of the surface layer occurs. According to the experiment, the best combination of the PEO coating properties (microhardness H V = 109.98 kg/mm 2 , maximum homogeneity, no surface roughness) is reached at an initial current density of i = 5 A/dm 2 , followed, in 9 minutes, reducing up to i = 3 A/dm 2 to maintain the process in the microarc mode; the total duration of treatment is 11 – 13 min. In doing so the hardness of the oxide layer surface in comparison with the unprotected alloy increases up to four times. The study of the influence of temperature and heat treatment time indicates that the resulting oxide coatings are not recommended to be used as hard and wear-resistant at temperatures above 300 °C. The research of the surface morphology of the samples shows that in the process of PEO a fine-grained structure is formed, which with a prolonged processing time tends to enlarge and agglomerate the cells. With a 10 min. duration of oxidation the formed oxide coating has a light gray color, its surface is uniform, which is explained by the incorporation of phosphates from the working electrolyte solution into the defective structure of the surface. However, the transition to the arc mode with a duration of oxidation more than 13 min. leads to substantial roughness and heterogeneity of the coating structure. The aggregate of the identified factors indicates the prospect of the research direction, further work will be aimed at obtaining oxide coatings with desired functional properties for aluminum alloys in various electrolytes with a minimum duration of oxidation.

Встановлено вплив режимів електролізу на склад і морфологію поверхні бінарних Co(Fe)-W і тернарних Fe-Co-W сплавів. Доведено, що нанесені в імпульсному режимі покриви бінарними сплавами відрізняються більш рівномірним розподілом компонентів по поверхні, меншим вмістом оксигену і глобулярною морфологією. Це пояснюється особливостями електрокристалізації сплавів в умовах нестаціонарного електролізу: під час імпульсу відбувається відновлення Fe 3+ до Fe 2+ , а оксовольфраматів – до оксидів вольфраму у проміжному ступені окиснення. В період паузи реалізуються процеси адсорбції реагентів, відновлення Fe 2+ до металічного стану, хімічного відновлення проміжних оксидів вольфраму ад-атомами гідрогену та хімічна реакція вивільнення лігандів. Застосування імпульсного струму дозволяє осаджувати тернарні Fe-Co-W з більш рівномірною поверхнею і розширити діапазон вмісту тугоплавкого компоненту в сплаві, а вихід за струмом процесу підвищується практично вдвічі до 70 – 75 % порівняно із гальваностатичним. Показано, що за фазовим складом бінарні покриви є твердими розчинами вольфраму в α-Fe або α-Co, тоді як тернарний Fe-Co-W є аморфно-кристалічним і містить фази інтерметалідів Co 7 W 6 і Fe 7 W 6 , а також α-Fe та цементиту Fe 3 C. Доведено можливість керування складом і морфологією поверхні вольфрамвмісних покривів із залізом та/або кобальтом застосуванням різних режимів та параметрів електролізу – постійного та імпульсного струму з варіюванням густини струму, тривалості імпульсу/паузи. Імпульсний електроліз сприяє підвищенню вмісту тугоплавкого компоненту та ефективності електролізу. Електролітичні сплави переважають за мікротвердістю основу зі сталі у 3–4 рази, причому підвищення вмісту вольфраму забезпечує підвищення механічних характеристик, за рахунок утворення інтерметалідів та аморфної структури покривів. За показниками покриви сплавами Co(Fe)-W і Fe-Co-W можуть ефективно використовуватись для зміцнення поверхонь зі сталі та чавуну, а також у ремонтних технологіях для відновлення спрацьованих деталей з наданням поверхні підвищених фізико-механічних властивостей.

The electrolysis modes affect on the quantitative and phase composition of the ternary Fe-Co-W and Fe-Co-Mo coatings is studied. It was established that the distribution of refractory components over the thickness of the coating varies in the opposite way with increasing duration of electrolysis – the molybdenum content increases and the tungsten one decreases. Amorphous-crystalline structure of alloys has been visualized by X-ray spectroscopy, including inter-metallic phases Co7W6, Fe7W6, Fe7Mo, Fe7Co, FeCo along with α-Fe and Fe3C. The size of coherent-scattering region of the amorphous part is of 6–8 nm. The formation of metallic tungsten and molybdenum additional phases has been detected for alloys deposited at pulse current which contributes microhardness Hμ increase up to 700 compared with direct current mode. Magnetic characteristics of Fe-Co-W(Mo) films were measured depending of deposition time. It was concluded that the content of magnetic phases in upper layers of Fe-Co-W deposits is higher than in the bottom ones and superior Fe-Co-Mo coatings. It qualitatively corresponds to W(Mo) content changes over the thickness.

The structure and the properties of the oxide films formed on titanium by means of plasma electrolytic oxidizing at direct current density of 1 – 5 A·dm−2 have been studied. Composition of citrate-pyrophosphate electrolytes with addition of iron triad metals’ sulfates were proposed for the formation of mixed oxide systems with the varied content of dopants. The range of voltages for the single-stage plasma-electrolytic oxidizing of titanium alloys VT1-0 and OT4-1 is of 120–160 V, and operating voltage decreases with rising concentration of dopant ions. As a result of oxidizing, metal-oxide systems TiOx·MOy (M=Fe, Co, Ni) we obtained. The surface morphology of mixed oxides was found to depend on the nature of a dopant and change from micro-porous for TiOx·CoOy to globular for TiOx·NiO, and at least toroidal relief for TiOx·FeOy coatings. It was established that the formed mixed oxide coatings of titanium with the metals of iron triad possess significant corrosion resistance; the highest value is inherent to the systems based on cobalt. It is shown that the incorporation of iron triad metals into the composition of oxide layers leads to an increase in the surface development degree. Obtained oxide systems exhibit catalytic activity in the model reaction of carbon (II) oxide conversion.

The influence of electrodeposition modes on the quantitative and phase composition of the ternary alloys Fe-Co-Mo (W) has been established. The application of pulsed electrolysis provides increasing molybdenum (tungsten) content up to 15–20 at%, at current efficiency of 70–75 %. The analysis of the refractory metals distribution over the coating thickness indicates an increase in molybdenum and decrease in tungsten content with an increase in the electrolysis time. The content of alloying metals in the growing deposits was simulated. The globular developed surface of Fe-Co-Mo(W) coatings is caused by refractory metals incorporation. The results of X-ray diffraction analysis indicate the amorphous-crystalline structure of alloys and intermetallic phases of Fe7Mo, Fe7Co, FeCo, Co7W6, Fe7W6 along with α-Fe and Fe3C. The coherent-scattering region size of the amorphous part is 2–8 nm. The magnetic characteristics of amorphous Fe-Co-W coatings have been established to be depending on deposition time. The conclusion, that the content of magnetic phase in upper layers of coating is greater than in the bottom ones due to decreasing tungsten concentration has been made. The Fe-Co-Mo coatings have been shown to be soft magnetic due to the presence of ferromagnetic phases in the surface layers. The microhardness of ternary coatings deposited in the pulsed mode exceeds the characteristics of ones obtained by direct current and is not inferior to the coatings with hard chromium.

We study the influence of the concentrations of the components of citrate electrolytes based on Fe(III) and the modes of electrolysis on the composition of the Fe–Co–Mo, Fe–Co–W, and Fe–Mo–W coatings. It is shown that the formation of ternary alloys is realized by the mechanism of competitive reduction of cobalt and tungsten (molybdenum) with iron. As the concentration of a ligand increases, the coating is enriched with a refractory component. However, the opposite trend is observed as the current density increases. The application of the pulsed electrolysis makes it possible to increase the rate of the process and to enhance the current efficiency by 70–75%. The dependence of the morphology of deposits on the nature and content of refractory components is determined by the methods of scanning electron microscopy and X-ray diffraction spectral microanalysis. The influence of the compositions of ternary coatings on their corrosion resistance in media with different acidities and on the catalytic activity in the electrochemical reaction of hydrogen release is analyzed. By the methods of polarization resistance and electrode impedance spectroscopy, it is established that the corrosion resistance of the coatings is higher than for the substrate material by 1.3–2.0 orders of magnitude. The dependence of the nature of corrosion inhibition on the composition of electrolytic alloys is investigated.

Создание газових сенсоров на основе точечных контактов существенно расширяет научные и технические возможности улучшения метрологических параметров чувствительных элементов. В ряду этих возможностей перспективным является использование нових газочувствительных материалов, в частности, тернарных металлических сплавов. В состав тернарного сплава Co – Mo – W входят металлы, которые широко известны в газовой сенсорике, но благодаря синергетическим эффектам , возникающим при электролитическом сплавообразовании, можно ожидать усиления специфических поверхностных свойств синтезированнных материалов. С целью разработки средств медицинской диагностики изучалась смесь газов, выдыхаемых человеком. При действии этого биологического материала на точечный контакт, матеріалом канала проводи мости котрого был сплав Co – Mo – W, получали отклики в виде сложных зависимостей сопротивления от времени с высоким уровнем воспроизводимости. Результат дает перспективу использования системы в диагностических целях. Вторым объектом изучения был газообразный водород. Исследования поведения точечного контакта, созданного на базе сплава Co – Mo – W, в среде этого газа позволяют сделать вывод о возможности использования сплава для разработки сигнализатора взрывоопасных концентраций водорода. В целом, полученные данные свидетельствуют о способности точечных контактов на базе исследуемого сплава показывать высокую чувствительность как по отношению к водороду, так и по отношению к отдельным веществам сложных газовых смесей., The creation of gas sensors based on point contacts significantly expands the scientific and technical possibilities for improving the metrological parameters of sensitive elements. Among these possibilities, the use of new gas-sensitive materials, in particular, ternary metal alloys, is promising.The composition of the ternary alloy Co - Mo - W includes metals that are widely known in gas sensorics, but due to the synergistic effects arising from electrolytic alloying, we can expect an increase in the specific surface properties of the synthesized materials. In order to develop medical diagnostic tools, breath gas was studied. Under the action of this biological material on a point contact, the material of the conduction channel of which was the Co – Mo – W alloy, received responses in the form of complex dependences of resistance on time with a high level of reproducibility. The result gives the prospect of using the system for diagnostic purposes. The second object of study was gaseous hydrogen. Studies of the behavior of a point contact created on the basis of Co-Mo-W alloy in the medium of this gas allow us to conclude that the alloy can be used to develop an indicator of explosive hydrogen concentrations. In general, the obtained data indicate the ability of point contacts based on the alloy to exhibit high sensitivity both to hydrogen and to individual substances of complex gas mixtures., Створення газових сенсорів на основі точкових контактів суттєво поширює наукові і технічні можливості покращення метрологічних параметрів чутливих елементів. В ряду цих можливостей перспективним є використання новітніх газочутливих матеріалів, зокрема, тернарних металевих сплавів. До складу тернарного сплаву Co – Mo – W входять метали, які широко відомі у газовій сенсориці, але завдяки сінергетичним ефектам, які виникають при електролітичному сплавоутворенні, варто очікувати посилення специфічних поверхневих властивостей синтезованих матеріалів. З метою розробки заходів медичної діагностики вивченню підлягала суміш газів, яку видихає людина. При дії цього біологічного матеріалу на точковий контакт, матеріалом каналу провідності якого був сплав Co – Mo – W, отримували відгуки у вигляді складних залежностей опору у часі з високим рівнем відтворюваності. Результат дає перспективу використання системи в діагностичних цілях. Другим об’єктом вивчення був газоподібний водень. Дослідження поведінки точкового контакту, створеного на базі сплаву Co – Mo – W, у середовищі цього газу дозволяють зробити висновок про можливість застосування сплаву для розробки сигналізатора вибухонебезпечних концентрацій водню. В цілому отримані дані свідчать про здатність точкових контактів на базі сплаву, який досліджувався, показувати високу чутливість як до газоподібного водню, так і до окремих хімічних речовин складних газових сумішей.

В статті наведено результати досліджень базових параметрів комплексних цитратних електролітів на основі заліза (ІІІ) для нанесення тернарних сплавів з кобальтом і молібденом. Метою роботи було визначення експлуатаційних покажчиків електроліту, таких як стійкість, в’язкість, електропровідність і буферна ємність, а також встановлення залежності їх зміни під дією важливого зовнішнього чинника – температури. Із застосуванням кондуктометричного методу було встановлено, що з підвищенням температури електропровідність електролітів прогнозовано зростає, а досліджувані розчини є сильними електролітами. Отримані значення енергії активації питомої електропровідності знаходяться в інтервалі 694–965 Дж/моль. Встановлено залежність коефіцієнта в’язкості електролітів від температури, зміна якого також узгоджується з основами теорії розчинів електролітів. На основі отриманих результатів визначено енергію активації молекулярного стрибка. Титриметричними дослідженнями було оцінено буферні властивості цитратних електролітів та проведено співставлення отриманих результатів з властивостями відомих електролітів для електроосадження гальванічних покривів сплавами іншого складу., The article presents the results of studies of basic parameters of complex citrate electrolytes based on iron (III) for the application of ternary alloys with cobalt and molybdenum. The aim of the work was to determine the performance of the electrolyte, such as stability, viscosity, electrical conductivity and buffer capacity, as well as to establish the dependence of their change under the action of an important external factor - temperature. Using the conductometric method, it was found that with an increase in temperature the electrical conductivity of electrolytes predictably grows, and the solutions under study are strong electrolytes. The obtained values of the activation energy of conductivity are in the range of 694–965 J/mol. The dependence of the viscosity of electrolytes on temperature is established, the change of which also agrees with the fundamentals of the theory of electrolyte solutions. Based on the results obtained, the activation energy of the molecular jump is determined. Titrimetric studies evaluated the buffer properties of citrate electrolytes and compared the results obtained with the properties of known electrolytes for electrodeposition of electroplated coatings with alloys of a different composition.

Analyzing of composition electrolytic coatings’ application for the metal surface protection is considered. It is established that using different components for coatings’ modification gives possibility to obtain surfaces with expanding exploitation properties, in particular, with improved wearing and anticorrosion resistance. The new approach for protecting details which are made from cast irons by obtaining two kinds of composition coatings from binary alloys iron-molybdenum and iron-tungsten is proposed. It is found that the modification of iron by refractory metals up to 37 wt. % leads to a noticeable change in the microstructure of the coatings’ surface. It is established that the incorporation of refractory metals into the iron matrix is a good way to increase the microhardness of the surface by 2.5–3.5 times and rising of the wear resistance by 40%, as well as decreasing the friction coefficient by 3-4 times in comparison with the cast iron substrate. The research results can be used for surfaces hardening and protection in different industries.

The processes of plasma-electrolytic formation of heteroxide coatings on titanium alloys for the photocatalytic disintegration of natural and technogenic toxicants are studied. Synthesis of coatings was carried out from aqueous diphosphate solutions in the galvanostatic mode. For a quantitative description of photocatalytic reactions, reaction rate constants were calculated from the linearized dependences lnCt/C0, where Ct is the current concentration of the azodye and C0 is the initial concentration of the reactant. The surface morphology of the coatings was studied by atomic force microscopy and visualized the results by reconstructing the relief in the form of 2D and 3D topographic maps. The morphological features of titanium (IV) oxide coatings and heteroxide composites containing zinc and / or copper oxides are analyzed. It has been shown that the specific surface remains an effective factor in controlling the photocatalytic activity of coatings; therefore, the establishment of the morphology of heteroxide composites, as well as methods for controlling this parameter of the target product, is an invariable component of a systematic study of such materials when establishing their functional properties. It is established that, in comparison with titanium oxide coatings, whose surface layers are characterized by toroidal mesostructures, heteroxide compositions have a more developed surface, which positively affects their functional properties. Subsequent heat treatment also has the same effect on coating properties. The rate constants of the photocatalytic decomposition of the methyl orange azodye, determined under similar conditions, were used to rank coatings of various compositions according to their functional properties. Thus, for the reaction on the surface of titanium oxide, the rate constant is 1.56∙10–3 min–1, while for the heterooxide layer TiO2·ZnO it increases to 5.8∙10–3 min–1. The coating of TiO2·ZnO is the most catalytically active, although the TiO2·ZnO·CuO system also accelerates the decomposition process with a degree of degradation of 25% for 60 minutes, further, the efficiency of the catalyst decreases., Исследованы процессы плазменно-электролитического формирования гетерооксидных покрытий на сплавах титана для фотокаталитической дезинтеграции природных и техногенных токсикантов. Синтез покрытий проводили из водных дифосфатных растворов в гальваностатическом режиме. Для количественного описания фотокаталитических реакций вычисляли константы скорости реакции из линеаризованных зависимостей lnCt/C0, где Ct – текущая концентрация азокрасителя, C0 – исходная концентрация реактанта. Морфологию поверхности покрытий изучали методом атомно-силовой микроскопии и визуализовали результаты путем реконструкции рельефа в виде 2D- и 3D-топографических карт. Проанализованы морфологические особенности покрытий титан(IV) оксида и гетерооксидных композитов, в состав которых входят оксиды цинка и/или меди. Показано, что эффективным фактором управления фотокаталитической активностью покрытий остается их удельная поверхность, поэтому установление морфологии гетерооксидных композитов, как и способов управления этим параметром целевого продукта, является неизменной составляющей системмного исследования таких материалов при установлении их функциональных свойств. Установлено, что в сравнении с покрытиями оксидом титана, для поверхностных слоев которого характерны торообразные мезоструктуры, гетерооксидные композиции имеют более развитую поверхность, что позитивно влияет на их каталитическую активность. Такое же воздействие на свойства покрытий оказывает и последующая термообработка. Определенные в аналогичных условиях константы скорости модельной реакции фотокаталитического разложения азокрасителя метилового оранжевого использованы для ранжирования покрытий различного состава по их функциональным свойствам. Так, для реакции на поверхности оксида титана значение константы скорости составляет 1,56∙10–3 мин–1, тогда как для гетерооксидного слоя TiO2·ZnO возрастает до 5,8∙10–3 мин–1. Покрытие TiO2·ZnO является наиболее каталитически активным, хотя система TiO2·ZnO·CuO также ускоряет процесс разложения со степеню деструкції 25 % в течение 60 мин, далее эффективность катализатора снижается., Досліджено процеси плазмово-електролітного формування гетерооксидних покривів на сплавах титану для фотокаталітичної дезинтеграції природних і техногенних токсикантів. Синтез покривів проводили з водних дифосфатних розчинів у гальваностатичному режимі. Для кількісного опису фотокаталітичних реакцій визначали константи швидкості реакції з лінеаризированих залежностей lnCt/C0, де Ct – поточна концентрація азобарвника, C0 – вихідна концентрація реактанта. Морфологію поверхні покривів вивчали методом атомно-силової мікроскопії та візуалізували результати шляхом реконструкції рельєфу у вигляді 2D- і 3D-топографічних карт. Проаналізовано морфологічні особливості покривів титан(IV) оксиду та гетерооксидних композитів, до складу яких входять оксиди цинку та/або міді. Показано, що ефективним чинником керування фотокаталітичною активністю покривів залишається їх питома поверхня, тому визначення морфології гетерооксидних композитів, як і засоби керування цим параметром цільового продукту, є незмінною складовою системного дослідження таких систем при визначенні їх функціональних властивостей. Доведено, що порівняно із покривами оксидом титану, для поверхневих шарів якого характерні тороподібні мезоструктури, гетерооксидні композиції мають більш розвинену поверхню, що збільшує їх каталітичну активність. Такий саме вплив на властивості покривів чинить і наступна термообробка. Визначені в тотожних умовах константи швидкості модельної реакції фотокаталітичного розкладання азобарвника метилового жовтогарячого застосовано для ранжування покривів різного складу за їх функціональними властивостями. Так, для реакції на поверхні оксиду титану значення константи швидкості становить 1,56∙10–3 хв–1, тоді як для гетерооксидного шару TiO2·ZnO зростає до 5,8∙10–3 хв–1. Покрив TiO2·ZnO є найбільш каталітично активним, хоча система TiO2·ZnO·CuO також прискорює процес розкладання зі ступенем деструкції 25 % протягом 60 хв, але далі ефективність каталізатору знижується.

У статті розглянуто вплив зміни технологічних параметрів виробництва композиційної кераміки на питомий об'ємний опір композиції а також на захисні властивості від впливу електромагнітного випромінювання. До технологічних параметрів було віднесено спосіб приготування, час усереднення сировинних матеріалів, тиск пресування і другого випалу. На підставі проведеного комплексу досліджень встановлено наступні технологічні параметри виробництва: тривалість помелу – 60 хв.; вологість прес-порошку – 6,2%; тиск пресування – 25 МПа; температура першого випалу – 1060 ° С; температура другого випалу – 1060 °С. Розроблена технологія може бути використана на підприємствах, які випускають керамічну плитку зі швидкісним режимом випалу. Отриманий матеріал може бути використано для захисту біологічних і технічних об'єктів від дії електромагнітного випромінювання. Подальші дослідження спрямовані на підбір глазурованого покриття для розробленої кераміки., The article considers the influence of the technological parameters of the composite ceramics production on the specific volume resistivity of the composition and, consequently, on the protective properties against the effects of electromagnetic radiation. The technological parameters included the preparation method, the averaging time of the raw materials, both the pressing and second calcination pressure. Based on the complex of studies carried out, the following technological parameters of production were established: duration of grinding – 60 minutes; the moisture content of the press powder is 6.2%; pressing pressure – 25 MPa; first calcination temperature – 1060 °С; temperature of the second calcination –1060 °C. The developed technology can be applicated at enterprises that produce ceramic tiles according to high-speed calcination. The resulting material can to protect biological and technical objects from the action of electromagnetic radiation. Further research at selecting a glaze coating for the developed ceramics is aimed., В статье рассмотрено влияние изменения технологических параметров производства композиционной керамики на удельное объемное сопротивление композиции и, следовательно, на защитные свойства от воздействия электромагнитного излучения. К технологическим параметрам было отнесено способ приготовления, время усреднения сырьевых материалов, давление прессования и второго обжига. На основании проведенного комплекса исследований установлено следующие технологические параметры производства: длительность помола – 60 мин.; влажность пресс порошка – 6,2 %; давление прессования – 25 МПа; температура первого обжига – 1060 °С; температура второго обжига – 1060 °С. Разработанная технология может быть использована на предприятиях, которые выпускающих керамическую плитку по скоростному режиму обжига. Полученный материал может быть использован для защиты биологических и технических объектов от действия электромагнитного излучения. Дальнейшие исследования направлены на подбор глазурного покрытия для разработанной керамики.

This chapter introduces the investigation of Al alloys plasma electrolytic oxidizing (PEO) and analysis of process characteristics. The research directs to set regularity of electrochemical obtaining (forming or formation) of nanostructured coatings mono- and mixed oxides which are incorporated with transition metals namely manganese. It is shown that the alloys surface and bulk composition heterogeneity complicates the alloys processing to produce a uniform layer of oxides. Electrolytes containing K4P2O7 and KOH as the basic component were used to homogenize the outer surface layer of aluminum alloys and to form uniform conversion covers, predominantly oxides. PEO in these electrolytes in the range of current densities 5…20 A/dm2 allows obtaining mixed oxide coatings which contained both matrix and doping metal oxides. It was found that the rising of both the permanganate concentration in the electrolyte and current density of treatment allows to enrich the surface layer of the coatings with oxides. The X-ray analysis confirms the incorporation of MnOx into the matrix of aluminum oxide. The modes for PEO of aluminum alloys have been proposed for producing conversion coatings containing Mn up to 36 wt%. Mixed oxide covers exhibit a developed surface and increased catalytic properties and corrosion stability. The complex of functional properties determines the possibility of their usage as promising materials for emission control technologies and also in systems of ICE waste gas purification.

Development of quantum selective sensors requires a detailed study of nature, kinetic parameters, and activation mechanisms of all phases of the cyclic switchover effect. Yanson point contact is the main tool to solve emerging tasks. When placed in an ion-conducting medium, it can function as an electrochemical gapless electrode system (GES). The transformations in the Yanson point-contact nanostructure are shaped by the quantum shell effect and the GES processes. We show that a GES in an electric field is as a system with a positive feedback which determines the dynamics of the point-contact resistance variation in an ion-conducting medium. Analysis of the experimental data on the dynamics of electric conductance and lifetime of dendritic Yanson point contacts during the cyclic switchover effect allows one to study the peculiarities of the processes that can enable the realization of the quantum mechanism of selective detection and lead to an enhanced sensitivity of point-contact sensors to liquid and gaseous analytes. A mathematical model for the anode destruction of dendritic copper point contacts during the cyclic switchover process is proposed and discussed.

The ternary Co–Mo–W (Zr) and Co–Fe–Mo coatings with the total content of refractory metals of 30–40 wt%, Co–W–Zr alloys with that of 12–26 wt% and Co–Fe–Mo are deposited from pyrophosphate–citrate electrolytes in pulse regime. The composition of the coatings as well as the surface morphology is shown to depend on the current density. A uniformly cone-shaped developed surface characterizing the coatings is due to the tungsten and molybdenum incorporation, but molybdenum-containing ternary coatings differs by the network of shallow cracks. The X-ray diffraction patterns reflect the amorphous and crystalline structure of ternary alloys. Phases of α-Co, intermetallic compounds Co3Mo, Co7Mo3, Co7Mo6, and traces of metallic molybdenum were detected in the coatings Co–Mo–Zr. The phase composition of Co–Mo–W deposits differs by the emergence of Co7W6 phase and traces of metallic tungsten, and there no any metallic W in the phase composition of Co–W–Zr electrolytic alloys. The corrosion behavior of the ternary coatings in alkaline medium studied by EIS shows the Co–Mo–Zr alloys are characterized by the highest corrosion resistance among the materials studied, and the results are more reproducible. Such behavior is due to the presence on the surface stoichiometric zirconium oxide ZrO2 with high both electrical resistivity and chemical stability. The coatings Co–Mo–W(Zr) and Co–Fe–Mo containing metallic phases of Mo or W are characterized by higher corrosion resistance. The mechanism and kinetics of electrolytic oxidation of methanol on electrodes with electrolytic ternary alloys coatings is determined. Based on the experiments carried out, we can conclude that the reaction of (CH3OH)S → (HCHO)S is the limiting stage, and it allows us to provide the process cycling and prevent the formation of carbon dioxide. The obtained data are indicative of a rather high electrocatalytic activity of ternary alloys, in particular, Co–Mo–Zr, for the reaction of methanol oxidation in the alkaline medium. Such catalytic properties can be explained by a higher degree of the surface branching, and the synergetic effect of the metals, in particular cobalt, molybdenum, and zirconium that are characterized by the different stable oxidation states and the affinity to oxygen.