Advanced Materials for Technical and Medical Purpose

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Authors: Alexandr V. Kabyshev, Fedor V. Konusov, Alexander L. Lauk, Alexey M. Lebedinskiy, Victor N. Legostaev, Egor A. Smolyanskiy
Abstract: In this paper the optical absorption characteristics of Al–Si–N coatings, deposited by magnetron sputtering on the substrates from silicon single crystals and glass were studied. The influence of conditions deposition on optical properties has been determined. The characteristics of interband and exponential absorption are determined by influence of localized states (LS) of defects continuously distributed in the band gap (BG) and reflect the influence on properties of crystalline and amorphous components material of coatings. The interband absorption is realized via the allowed indirect transitions through the optical gap 2.7–2.8 eV and direct transitions through the gap 3.8–3.96 eV. The interrelations between the parameters of interband and exponential absorption are typical for the naterials, whose properties are determined by a static and/or dynamic disordering of the crystal lattice by the defects of a different nature. Maximal average value of the BG width is 4.8–5.1 eV in the scope of semiclassical analysis applied to amorphous and strongly defective materials. The optical parameters of deposited coatings are changed in correlation with a changing of the mechanical characteristics in dependency on the nitrogen pressure.
Authors: Olga V. Krysina, Vladimir V. Shugurov, Nikolay Koval, Nikita Prokopenko
Abstract: The paper reports on a study to optimize the modes of plasma-assisted vacuum arc deposition of molybdenum nitride (MoN) coatings. It is shown that the parameters of plasma assistance influence the coating properties and that varying the ion current ratio in the metal-gas plasma makes possible MoN coatings with high hardness and high wear resistance.
Authors: Nikita V. Voitenko, Artem S. Yudin, Natalia S. Kuznetsova
Abstract: The investigation of possibilities of the plasma blasting technology is considered. The method is based on the initiation of a pulsed electric discharge inside the solid dielectric material. The expanding plasma channel generates a shock wave which in the vicinity of the channel (1–2 mm) transforms into the elastic wave with an expressed region of tensile tangential stresses that in turn stimulate the radial crack nucleation. The efficiency of solid destruction at shock-wave action strongly depends on the pulse parameters. The high-current pulse must fulfil the requirements to such parameters: the high-rate of rising edge (0.1–10 ms) and pulse duration (≥ 200–300 ms). The experimental results have shown that the optimal ratio of the borehole depth is 0.6–0.7 from the oversize rock height. For splitting rock massive off the borehole depth should be at least 2 and not more than 5 electro-explosive cartridge lengths and distance between the boreholes should be equal to 1–2 of the boreholes depths. On the basis of the experimental results the recommendations for the electro-discharge destruction and splitting off oversized rocks are presented.
Authors: Nikolay A. Yavorovsky, Alexey V. Pustovalov, Sergey P. Zhuravkov, Olga S. Lutoshkina
Abstract: The paper describes the research into the effect of the energy supplied to the conductor at the time of explosion on the particle size distribution of aluminum powders obtained. Aluminum powders consist of at least three fractions with the average particle size of 20-100 μm, 1-5 μm, and 50-900 nm. The yield of each fraction and average particle size are determined by the level of energy supplied to the conductor.
Authors: Sergey P. Zhuravkov, Galina L. Lobanova, Alexey V. Pustovalov, Vasilii V. Fedorov, Gennadii A. Pribytkov, Luiza V. Nadeina
Abstract: The results of electrospark dispersion of the metallic titanium loading in aqueous medium are presented in the paper. Raster electronic microscopy, X-ray phase analysis and BET method were used to investigate properties of the obtained powder. Values of specific surface are given in the paper, and morphology and structure of the obtained powders are studied. It is established that chemical and phase composition of the obtained powders is identified by properties of the molten titanium to interact with the dissolved in dispersion medium gaseous products.
Authors: Galina Kholodnaya, Roman Sazonov, Denis Ponomarev, Artyem Poloskov
Abstract: The paper presents the results of the experimental investigation of the pulsed electron beam propagation propagated in a drift tube filled with oxygen. The pressure was 50, 300, and 760 Torr in the drift tube. The experiments were carried out using a TEA-500 pulsed electron accelerator (450 kV accelerating voltage; 10 kA electron beam current; 80±1 ns pulse duration to the base; up to 200 J pulse energy; and 5 cm diameter beam). The electron beam was propagated in the drift tube (40 cm long), 14 cm in diameter composed of two sections equipped with two reverse current shunts. The experiments were carried out which fixed the absorbed dose registered on the walls of the drift chamber.
Authors: Nurken E. Aktaev, Alexander Y. Pak
Abstract: The theoretical model for investigation of the electron beam propagation in the gas medium is developed. The main feature of the model is the possible to analyze the time evolution of the differential current which allows obtaining the energy distribution function of electron. The equations for electromagnetic fields created by the electron beam are the time dependence function. The elastic collision and ionization are considered as a basic interaction processes between beam and gas medium.
Authors: Sergey M. Martemyanov
Abstract: The electrical treeing phenomenon is being actively studied in relation to polymer dielectrics like epoxy resin and polyethylene. In these materials treeing is the cause of degradation and failure of insulation parts. However, treeing is also found in other materials, where it can be used purposefully. Peculiar kind of treeing can be observed in solid fossil fuels. There are significant differences in the mechanism of treeing in solid fuels and organic dielectrics. These differences are specified by physical structure and chemical content of solid fuels, and also by thermal decomposition of organic matter under discharge influence. Treeing in solid fossil fuels leaves conductive tracks in rock. This allows using it in processing technologies, including in situ conversion.
Authors: Ilya Vlasov, Sergey V. Panin, Viktor Sergeev, Vasilii Naidfeld, Pavlo Maruschak, Boris B. Ovechkin
Abstract: The structure of the heat resistant 12Cr1MoV steel modified by Zr+ ion beam treatment was investigated by optical, scanning electron and transmission electron microscopy as well as X-ray diffraction methods. It was shown that the modification occurs over the entire cross section of the irradiated specimen with thickness of 1 mm. Changes in mechanical properties under static, cyclic and dynamic loading of the specimens after the treatment are interpreted in term of structural modifications.

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