Increasing Wear Resistance of Alpha- and Beta-Titanium Alloy by Anodic Plasma Electrolytic Boriding |
Author : Kusmanov S.A., Tambovsky I.V., Kusmanova I.A., Belkin P.N. |
Abstract | Full Text |
Abstract :The effect of anodic boriding regimes on the structure of the modified layer and the wear characteristics of the treated titanium alloy was studied. The layer structure, its phase and elemental composition were investigated using X-ray analysis and electron microscopy with energy dispersive analysis. The surface roughness and microhardness distribution were measured by standard methods. The wear characteristics of the borided alloy were studied under dry friction conditions against bearing steel as counter-body. It was found that the modified layer contains titanium dioxide (rutile) and a solid solution of boron in titanium with precipitates of the beta phase. A fivefold enhancement of the wear resistance of the alloy due to an increase in hardness and a decrease in roughness is reached by anodic boriding in a solution of boric acid and ammonium chloride at 850ºC–900°C for 5 minutes. |
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Implementation of Nanostate Phenomenon in Materials Science of Functional Nanocomposites Based on Industrial Polymers |
Author : Avdeychik S.V., Goldade V.A., Struk V.A., Antonov A.S., Ikromov A.G. |
Abstract | Full Text |
Abstract :The conceptual directions of creating functional composites based on polymer matrices for metal-polymer systems are considered. An algorithm has been developed to develop a methodology for the implementation of the nanostate phenomenon in materials science and in the technology of composites and metal-polymer systems. The methodological principles of the implementation of the nanostate phenomenon in materials science and in the technology of functional materials based on polymer matrices for metal-polymer systems with high performance characteristics are proposed. |
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On Differences in Regularities of Realization of Instability of Kelvin-Helmholtz on Flat, Cylindrical, and Spherical Charged Interfaces of Environments |
Author : Grigoriev A.I., Shiryaeva S.O., Koromyslov V.A. |
Abstract | Full Text |
Abstract :Features of realization of instability of Kelvin-Helmholtz on the charged interface the ideal conducting liquid – the ideal dielectric environment are investigated at various interface geometry: flat, cylindrical, and spherical. It is noted that for a flat interface in the region of its stability to each wave number there correspond two waves with various frequencies running in one direction. With an increase in speed, the difference of frequencies decreases, and at the time of realization of instability of Kelvin-Helmholtz (in the region of instability), it became zero, and there appears one wave whose amplitude exponentially increases in time. For a cylindrical border, the situation is same, but there are distinctions connected with the existence of the azimuthal symmetry of waves. In case of a spherical interface, such effect is not present, the change of the modes of the existence of waves is different: the oscillatory instability like Kevin-Helmholtz is implemented at the paired interaction of the modes, and at a further increase in speed, it is replaced by a periodic instability, however, the general picture of the realization of instability is significantly more difficult. It is supposed that the reason of such distinction of the realization of instability is connected with the extremity of the surface area of the sphere and its infinity in one measurement for the cylindrical limit of the section and infinity in two mutually perpendicular directions for the flat one. |
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Synthesis and Electrochemical Behavior in Redox Reaction with Lithium of K,Na (V-Oxide Compounds) |
Author : Apostolova R.D., Shembel E.M. |
Abstract | Full Text |
Abstract :Heterogeneous vanadium-oxide compounds (bronzes, vanadates) attract the attention of developers of lithium batteries due to an increased structural stability of those oxides in the redox reaction with lithium as compared with the resistance of V2O5 oxide, a traditional intercalation electrode material for Li-batteries. Structural stabilization improves the discharge characteristics of Li-batteries based on potassium-containing and sodium-containing vanadium oxide compounds. In this work, the combined effect of potassium and sodium ions on the electrochemical transformation of vanadium oxide compounds in electrodes for usage in a Li-battery was investigated. According to the data of the X-ray phase analysis, dispersed deposits were obtained at the anode, depending on the composition of the electrolyte. From the solutions of potassium metavanadate in the presence of sodium ions, the deposits contain Na5V12O32 and KV5O13 vanadates; from the solutions of vanadyl sulfate in the presence of potassium and sodium ions, vanadates Na10V24O64 and KV5O13 are formed. The evaluation of the electrochemical parameters of the synthesized material indicates the possibility of its use in Li-batteries. The cycling efficiency of vanadates obtained from vanadyl sulfate solutions in thin-layer ballastless electrodes of a lithium battery exceeds that of V2O5 oxide. The positive combined potassium-sodium effect can be useful for the implementation of thin-layer lithium batteries based on electrochemically synthesized K,Na (V-oxide compounds) obtained from a solution of vanadyl sulfate. |
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On the Force of Electrostatic Interaction between Two Conducting Disks |
Author : Grashchenkov S.I. |
Abstract | Full Text |
Abstract :Electrostatic interaction of two conducting objects with preset charges on their surfaces in a zero external field is considered. The electrostatic induction is taken into account. The calculations are carried out by the higher order h-adaptive finite element method. The force of interaction between two conducting coaxial discs is presented. The interaction of an object in the form of a disk and an object in the form of a ball is also considered. Using numerical calculations, it is shown that with increasing the distance between the objects, already at distances comparable with the size of them, the force of interaction between a charged and an uncharged object is determined mainly by the shape of the uncharged object. |
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Investigation of Corrosion Behavior of Coatings Obtained on Steel by Electrospark Alloying with Manual Vibrator of Increased Frequency |
Author : Koval’ A.V. |
Abstract | Full Text |
Abstract :The comparative corrosion resistance in acidic, alkaline, and neutral environments of pure metals (steel, nickel, titanium), and of electrospark-alloyed coverings from nickel and titanium received on steel at high-frequency electrospark alloying is investigated. It is established that the phase structure, roughness, and porosity of the received coverings depend on the material of an electrode and on the modes of coatings deposition affect the corrosion behavior. A positive influence of high-frequency alloying with nickel and titanium on an increase in the corrosion resistance of a steel surface is shown. |
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Whey: The State of the Art. Part I. Classification, Composition, Properties, Derivatives, Applications |
Author : Paladii I.V., Vr?bi? ?.G., Sprinci?n C.G., B?l?g? ?.K. |
Abstract | Full Text |
Abstract :The current state of the art on studying whey is presented. The properties of whey, its chemical composition, classification, and derivatives are represented; the emphasis is made on the usefulness of the valued components of a dry substance and the necessity to develop new technological processes. The protein composition and the characteristics of the whey protein derivatives are presented. The functional and nutritional properties of the whey proteins and products on their basis and the application of whey derivatives in food industry are described. The curative properties of whey and its derivatives (antioxidant, immunomodulatory, stimulatory, antitumor properties) are determined by different mechanisms of the actions associated with their functional properties. |
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Technological Aspects of Estimation of Temperature in Metals When Forming Coatings by Heterophase Transfer and Microarc Oxidation |
Author : Kuznetsov Yu.A., Markov M.A., Kravchenko I.N., Krasikov A.V., Velichko S.A., Chumakov P.V., Kulakov K.V. |
Abstract | Full Text |
Abstract :The article considers the technological aspects of temperature estimation in an aluminum sample with a possible formation of an aluminum-containing coating on its surface using a combined technology of cold gas dynamic deposition and microarc oxidation. Experimental studies results of the temperature flow distribution over the thickness of the metal surface under cold gas-dynamic spraying are presented. The temperature of the heat flow during spraying varied from 200ºC to 600°C. It was found that the operating temperature of an aluminum substrate with a thickness of 8 mm at standard thermal deposition modes does not exceed 120°C, which is one of the advantages of the used here technology over the known methods of plasma and magnetron sputtering. The estimation of the temperature effect of microarc oxidation on the surface of a sample depending on various technological modes is given. It was found that the surface temperature of the sample oxidized in an alkaline electrolyte with liquid glass additives at current densities of 20–30 A/dm2 does not exceed 90°C, which shows the absence of thermal transformations. |
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Experimental Studies for the Receiving Surfaces of Solar Flat Collectors |
Author : Kuvshinov V.V., Morozova N.V., Abd Ali L.M., Krit B.L., Al-Rufaee F.M., Issa H.A. |
Abstract | Full Text |
Abstract :This paper presents the results of the studies of the energy characteristics of a solar collector with a selective receiving surface. When using special technologies for applying high-quality selective coatings to absorbers of solar collectors, it is possible to significantly increase the conversion coefficient of the incident solar radiation flux. The paper presents the results of studies of flat solar collectors serving to heat the coolant used mainly for the needs of hot water supply for individual consumers. In the experiments conducted, flat solar collectors with an absorber made of copper and stainless steel were used. Studies have shown that it is possible to more fully use the capabilities of one or another solar collector, depending on the operating mode of the entire solar hot water supply system. The presented studies were carried out by the staff of the Department of Renewable Energy Sources and Electrical Systems and Networks of the Sevastopol State University at the Institute of Nuclear Energy and Industry. Tests have shown that solar installations for the direct conversion of a radiation flux into thermal energy have a significant conversion factor compared to that of the solar power generating systems. Solar heat supply systems are used for private consumers and, in most cases, for heating hot water, and their use for heat supply systems allows, under certain conditions, to achieve high energy indicators. Solar power plants can be used in many southern regions of the Russian Federation; with their help it is possible to provide autonomous consumers with heat and hot water, while significantly saving fossil fuel and reducing harmful emissions into the atmosphere. In the Crimean region, the proposed systems can be most efficiently used in the spring-summer-autumn period, i.e. from May to September, which will significantly improve the environmental situation. |
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