Articles

 


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1.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-3-11
УДК 330.3:553.493
Doriomedov M.S., Sevastyanov D.V., Shein E.A.
TECHNOLOGICAL, INSTITUTIONAL AND ECONOMIC TRENDS IN THE INDUSTRY OF RARE AND RARE-EARTH METALS (review)

The paper is devoted to the systemization of global trends in the industry of rare and rare-earth metals. The trends of the three types (technological, institutional and economic) were revealed and discussed.

The first section of the article contains description of the main technological trends directed to rationalization of mining, production and processing of rare and rare earth metals. The presented examples suggest advisability of automation implementation for mining operations as well as for extraction of rare and rare-earth metals from wastes and new, non-conventional sources.

The second section includes data on institutional trends directed to development of industry of rare and rare-earth metals. Some examples of such trends from USA, EC and Russia were presented. EC experience in the foundation of industry association and the corresponding government measures are of special interest.

The third section contains the main economic trends allowed to reveal the promising fields of demand for rare and rare-earth metals.

Based on the presented data, it was concluded that the revealed trends would have a significant influence on industry of rare and rare-earth metals (both worldwide and in the Russian Federation) on a long-term horizon.

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2.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-12-25
УДК 678.8
Petrova G.N., Perfilova D.N., Starostina I.V., Sapego Yu. A.
RESEARCH OF WAYS OF COMBINATION POLYURETHANE THERMOPLASTICS WITH FLUOROPOLYMERS

The present article is devoted to consideration of questions of combination of thermoflexible polyurethane of brand Vitur-TM on the basis of simple polyether with In/6 fluoroelastomers SKF-32 and SKF-264.

Fluoroelastomers represent independent class of fluoropolymers of special purpose. On chemical and physics and technology properties they considerably exceed hydrocarbonic and natural rubbers and are irreplaceable material for manufacturing of the rubber products functioning in contact with fuels, oils, acids and other hostile environment at high temperatures. Introduction of fluoroelastomers in compounding of thermoflexible material allows not only to increase the working temperature of polyurethane, but also to provide the increased firmness of fuels and lubricants.

Ways of combination of thermoflexible polyurethane of brand Vitur-TM with fluoroelastomers of the specified brands one – and two-phasic ekstruziya are investigated; with use of vulkanizuyushchy agents for fluoroelastomers and without them; with different options of introduction of components.

The optimum way of combination of components - two-phasic ekstrudirovaniye of mix of initial components (composition on the basis of SKF-264B/6 rubber and diolny vulkanizuyushchy system) when there is the most complete combination of components at maximum level of physicomechanical properties of the received material is defined. It is established that blend thermoelastoplastic (STEP) made by the way of ekstruziya from previously mixed in the bunker of ekstruder of polyurethane and fluoroelastomer possesses increased resistance to TS-1 fuel and MS-8p oil in comparison with initial polyurethane Vitur TM.

The received results will allow:

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3.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-26-33
УДК 678.8
Sarychev I.A. S, Serkova E.A., Khmelnitskiy V.V., Zastrogina O.B.
THERMOSETTING BINDERS FOR AIRCRAFTFLOOR PANEL MATERIALS (review)

Polymer composite materials are gradually replacing metals in the civil and military aviation industry, while providing not only a general reduction in mass, but also increasing the strength characteristics of the aircraft. To date, the proportion of polymeric composite materials in the design of the aircraft can reach 50% by weight and much of it is concentrated in the interior decoration materials, such as: panels of walls, floors, ceilings, partitions, chairs and much more. Three-layer honeycomb panels (TLHP) are widely used to create interior and floor panels for aircraft, thanks to its lightness, high specific strength, rigidity and processability. The main requirements for binders in the prepreg for TLHP are: fast curing cycle, sufficient adhesive strength to the honeycomb core, moderate physicomechanical and thermal characteristics of the cured matrix, low cost. A separate line is the requirements for fire safety cellular interior panels, which are spelled out in the Aviation Rules AP-25 (analogue FAR-25).

The main types of binders for creating interior panels are phenol-formaldehyde and epoxy. In the domestic aviation industry, until recently, binders developed at FSUE “VIAM”, such as EP-2MK, 5-211BN, FPR-520, etc., were used for TLHP.

The world leaders in the production of binders and prepregs for the interior of aviation equipment are the companies Gurit, Huntsman, Henkel, Cytec, TenCate, Hexion, Gill, which are currently pushing domestic interior materials from the market.

Despite the cheapness of phenol-formaldehyde binders and high fireproof characteristics of plastics, honeycomb panels based on them meet the strength requirements only for the production of interior elements from them. For the production of floor panels in domestic and foreign practice using epoxy binders that provide the required str

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4.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-34-41
УДК 620.1
Yakovenko T.V., Bukharev G.M., Bobyreva T.V., Pykhtin A.A., Oparina L.A., Parshina L.N.
BIOCIDAL ADDITIVES SELECTION FOR FOAMED POLYURETHANES MODIFICATION

Existing polyurethane materials are quite actively affected by micromycetes and bacteria. Modification of the formulations of these materials with modern biocidal additives will add them resistance to the effects of microbiological factors, thereby ensuring the durability of products and construction, as well as the preservation of functional properties during the period of exploitation.

To combat microbiological damage to polymers, different antimicrobial organic and inorganic additives are used. Among bactericidal and fungicidal preparations, polymeric guanidine derivatives are interesting due to wide spectrum of action. “Anavidin” is the one of the most perspective biocidal preparation from the class of polyalkyleneguanidine. A feature of the new preparations based on polyhexamethylene guanidium salts is that their antibacterial activity varies little under the influence of the external environment. The great potential of polyguanidines is associated with the relatively high reactivity of guanidine groups. While low molecular weight compounds lose their biocidal properties during any chemical transformation, the biocidal properties of polyguanidines are preserved in many chemical reactions, due to guanidine groups are combined into a common polymer chain, and only some of them are involved in a chemical reaction; at the same time, unchanged groups retain biocidal properties of the new compound. Aqueous solutions of salts of polyhexamethylene guanidine can also stabilizating matrices of silver nanoparticles. Silver nanoparticles are the most common biocide among inorganic materials. A promising research is the possibility of using combined biocidal additives, including organic and inorganic components, to add polyurethane foams and elastomers increased resistance to microbiological factors.

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5.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-42-49
УДК 666.7
Belyachenkov I.O., Shchegoleva N.E., Chaynikova A.S., Vaganova M.L., Shavnev A.A.
SILICON NITRIDE CERAMIC MATERIALS FOR AVIATION GTE BEARINGS AND METHODS OF MANUFACTURING (review)

This article addresses the problem of creating ceramic materials for the manufacture of ceramic and hybrid bearings of aircraft gas turbine engines (GTE). A comparative characteristic of steel and ceramic bearing materials based on silicon nitride, silicon carbide, aluminum oxide, and zirconium oxide is given.

The use of silicon nitride based ceramics is proposed as a promising material. Silicon nitride ceramic materials are characterized by high mechanical characteristics, are resistant to aggressive media and high temperatures, as well as wear resistance and low friction coefficient.

The structure of α- and β-modifications of silicon nitride is considered, as well as the α→β phase transition occurring during the liquid-phase sintering of silicon nitride powders.

The methods of obtaining silicon nitride powders are briefly affected: an economically viable process of self-propagating high-temperature synthesis (SHS) and a plasma-chemical method, which makes it possible to obtain ultrafine powders.

The problem of obtaining highly sintered materials based on silicon nitride is highlighted due to the covalent nature of Si3N4 bonds. It is shown that the introduction of oxide or nitride sintering additives that form a liquid phase during sintering, as well as the use of methods of sintering under pressure (hot pressing, hot isostatic pressing) allows to solve this problem.

Methods for the manufacture of ceramic nitride silicon materials, their advantages and disadvantages, as well as the characteristics of materials obtained using these methods are considered.

The data on the creation of nitride silicon ceramics with dry lubricants are given, which make it possible to reduc

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6.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-50-58
УДК 621.762
Batienkov R.V., Efimochkin I.Yu., Khudnev A.A.
THE RESEARCH OF A SPECIFIC ELECTRICAL CONDUCTIVITY OF Mo–W POWDER ALLOYS OBTAINED BY SPS

In this work a metal powder alloy of tungsten and molybdenum was obtained. The powder mixture with the required tungsten content was compacted by the method of spark plasma sintering. Sintering modes were different. Samples for measuring the specific electrical resistance were made from the sintered billets and their density was determined, then microsections were made and the microstructure was investigated. The goal of this work was to study the specific electrical resistance of MW alloys and to find out the main factors influencing it.

As a result, it was found that the values of electrical resistivity for an alloy with 20% wt. tungsten are within the range of 7,83·10-8 to 10,60·10-8 Ohm·m. depending on the sintering temperature; for an alloy with 30% wt. tungsten these values are within the range of 7,83·10-8 to 10,60·10-8 Ohm·m. The specific electrical resistance of alloys increases with the increase of sintering temperature and reaches it’s maximum values at a sintering temperature of 1800 C. The values of electrical resistivity for an alloy with 20% wt. tungsten are always less than those values for an alloy with 30% wt. at the same sintering temperature and porosity because of the formation of solid solution which electrical resistivity increases with the increase of tungsten content. It was found that at all sintering temperatures the values of electrical resistivity correlate with porosity. However, other structural factors, such as the grain size of the phases and the number of oxide inclusions greatly influence this characteristic at sintering temperatures of 1400 and 1600°C. It is shown that an increase in the grain sizes of both the main phase and oxide inclusions leads to a decrease in the electrical resistivity of the alloys, which is associated with a decrease in the length of the g

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7.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-59-66
УДК 669.046.516.2
Piskorsky V.P., Valeev R.A., Korolev D.V., Morgunov R.B., Rezchikova I.I.
TERBIUM AND GADOLINIUM DOPIN G INFLUENCE ON THERMAL STABILITY AND MAGNETIC PROPERTIES OF SINTERED MAGNETS Pr–Tb–Gd–Fe–Co–B

It is shown theoretically that sintered PR–Tb–Gd–Fe–Co–B magnets containing terbium have a higher saturation magnetization compared to the magnets of similar composition doped with dispersion. The calculated value of the temperature coefficient of induction of the main magnetic phase in the region -60÷120°C is determined, which makes terbium-based magnets the most temperature-stable of all known rare earth magnets. The decreasing dependence of the bulk content of the main magnetic phase 2-14-1 on the atomic concentration of cobalt in the sintered material (Pr,Tb)–(Fe1-yCoy)–B. This dependence shows that the properties of the finished magnets deteriorate with increasing Сo сoncentration, despite the improvement of the properties of the phase 2-14-1. The amount of phase 2-14-1 in sintered materials (Pr,Tb)–(Fe1-yCoy)-B is reduced from 89 to 79 vol. % with an increase in cobalt content from y=0,20 to y=0.45 at. %. The content of the main magnetic phase in terbium-based magnets is twice higher than in similar materials, where instead of terbium dysprosium is used. The expected gain in magnetization of permanent magnets due to the increase in the proportion of phase 2-14-1 levels small economic losses from the use of more expensive terbium instead of dysprosium. It is found that in the range -60÷120°C the module of the temperature coefficient of induction decreases in absolute value with an increase in the magnetic moment of the «heavy» rare-earth metal ion in the series of terbium-dysprosium-gadolinium. The calculation of the temperature coefficient of induction in the molecular field approximation for phase 2-14-1 in sintered magnets (Pr,Tb)–(Fe1-yCoy)–B deviates from the experimentally determined value by no more than 0.005% K-1. Low TCI values in sintered magnets (Pr,

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8.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-67-75
УДК 530.152.1530.152.1
Morgunov R.B., Koplak O.V., Talantsev A.D., Korolev D.V., Piskorsky V.P., Valeev R.A.
THE PHENOMENOLOGY OF THE MAGNETIC HYSTERESIS LOOPS IN MULTILAYER MICROWIRES α-Fe/DyPrFeCoB

Microwires manufactured by the method of ultra-fast cooling of the melt demonstrate stratification into the soft magnetic phase α-Fe and the soft magnetic amorphous shell DyPrFeCoB. The rare-earth amorphous shell wins in comparison with the everywhere created glass shell because, keeping protective properties of a microwire, the amorphous shell in addition gives: flexibility and lack of fragility, the increased coefficient of magnetostriction in comparison with glass, own unique magnetic properties which in combination with exchange interaction with a kernel, can lead to emergence of new functional properties of microwires.

The analysis of the local shape of the magnetic hysteresis loops, recording excavated using the Kerr microscope in different points of the multi-layered coaxial microwire α-Fe/DyPrFeCoB. Depending on the distance from the ends of the microwire, where the demagnetization field makes a significant contribution to magnetization, hysteresis loops of different forms are obtained. The most significant for practical application fragments of the microwire demonstrate a rectangular hysteresis loop with an exchange displacement, as well as a hysteresis loop with 4 equilibrium levels of magnetization by the type of spin-valve devices.

Variations in the thickness of the core α-Fe and rare-earth sheath DyPrFeCoB Mick-reproved along with a change in the stray field as the distance from its end over-represent the variability of the local magnetic hysteresis loops recorded in its different parts. There are three main types of hysteresis loops – near the end of the microwire there is a chamfered loop of complex shape «butterfly», closer to the middle of the microwire there is a loop with several stationary levels of magnetization (up to four), or a rectangular loop with displacement. The last two types of gyro-steresis loop

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9.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-76-83
УДК 620.1
Krivushina A.A., Bobyreva T.V., Goryashnik J.S., Bukharev G.M.
STUDY OF MICROORGANISMS THE DESTRUCTORS OF FUNCTIONAL POLYMERIC MATERIALS EXPOSED UNDER CONDITIONS OF TROPICAL CLIMATE SIMULATION

Non-metallic materials and products in connection to expansion of their use constantly get into different operating conditions, where they are exposed to a variety of climatic and biological factors. The microorganisms impact on different materials is particularly significant in a humid tropical climate – microbiological communities of this climatic and geographic areas characterized by the highest level of biodiversity in the world. In Russia there are no own territories with a humid tropical climate, due to this fact the demand for microbiological resistance testing under humid tropical climate simulation occurred. For this task there was selected for the optimal conditions a Tropical block of New Fundal Conservatory of the Main Botanical Garden named after N.V. Tsitsin. Functional polymeric materials were exposed for 18 months under imitation of tropical climate weathering conditions. In exposition were used samples of rubber and sealant.

10 strains of microscopic fungi were isolated after exposure from the samples surfaces and thereafter their species identified along with theirs occurrence frequency counting. The dominant micromycetes species were Penicillium lanosum and Cladosporium sphaerospermum. Slightly less common were two other species of same genera Penicillium sp. and Cladosporium oxysporum. The species Aspergillus ochraceus. Rhizopus oryzae, Aspergillus terreus, Acremonium sp., Stachybotrys chartarum, Trichoderma viride are singularly met. Almost all isolated species of fungi are known as destructors of polymeric materials in different climatic zones and environmental conditions. Some species and genera of fungi are part of the test cultures sets of Russian and international standards used in laboratory fungal resistance testing of materials and products. The isolated cultures of micromycetes are of interest for their further use for research purposes, as well as for accelerate

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10.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-84-91
УДК 620.1:678.073
Laptev A.B., Nikolaev E.V., Kurshev E.V., Goryashnik J.S.
FEATURES OF BIODEGRADATION OF THERMOPLASTICS BASED ON POLYESTERS IN DIFFERENT CLIMATIC ZONES

Results of research of samples of materials (polyethylene terephthalate, polystyrene) in water of the Black sea (Gelendzhik) and the mineralized water of a circulating cycle of the petrochemical plant (Ufa) are resulted.

The study of samples of materials (polystyrene and polyethylene terephthalate) allowed on the basis of the analysis of strength properties, deposits on the surface to assess the stages of the process of bio fouling and biodegradation at the initial stage – up to 60 days of exposure.

Taking into account the peculiarities of the life of microorganisms and microalgae, it is possible to make an assumption about significant oxygen content at the first stage of exposure on the surface of the sample. Oxygen as an active oxidizer leads to reactions of additional cross-linking of polymers, both polystyrene and PET, which affects the strength characteristics of polymers. Values of the maximum load at destruction of samples on in the first days of exposure at first increase at the expense of building of additional communications between macromolecules of polymers reactions with oxygen at active photosynthesis of algae. At the next stage of exposure, the loads are reduced due to the fouling of autotrophic bacteria, which oxidize organic products in the process of life and as products of metabolism form organic acids, carbon dioxide and hydrogen sulfide, which are concentrated under the biofilm significantly reducing the pH at the surface. Acid solutions actively penetrate into the polymer volume and plasticize it, reducing the maximum tensile stress of the sample.

It is established that after 30-40 days of exposure, the polymer samples are saturated with moisture and the surface is destroyed by the products of bacterial metabolism, which leads to a drop in both the strength and plasticity of polystyrene and polyeth

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11.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-92-111
УДК 620.1:678.8
Grinevich A.V., Yakovlev N.O., Slavin A.V.
THE CRITERIA OF THE FAILURE OF POLYMER MATRIX COMPOSITES (review)

The paper deals of the main failure criteria of polymer matrix composites, used in modern simulation’s software systems, by calculating the strength of composite plates and shells.The limit criteria (for stress and strain) are noted, also the polynomial failure criteria: Tsai-Wu, Tsai-Hill, Yamada-Sun, Hoffman, Cowin, Hankinson, Norris, and separated modes failure criteria: Puck (in various modifications), Hashin, Christensen, LaRC, Cuntze and others. Much attention is given to the theoretical background of the criteria and the applied approaches for the calculation of the strength of composite materials. It is analyzed criteria for first-ply-theory for composites, or for last-ply-theory (for progressive damage of structures).  The criteria can be divided into: limiting values criteria — the simplest ones that do not require complicated calculations or additional experimental studies; interactive criteria - combining of the stress tensor components by a general, easily analyzed, polynomial equation; criteria for the type of destruction - the most complex, piecewise-defined functions, considering different types of failure separately. The presented criteria may have different accuracy of the description of the properties of the polymer composite materials. Without enough experimental test data, it is necessary to choose the most conservative result at all. According to the demonstrated results, the criteria rather accurately predict the failure of unidirectional polymer composites.

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12.
dx.doi.org/ 10.18577/2307-6046-2019-0-7-112-124
УДК 620.193
Movenko D.A., Laptev A.B., Golubev A.V., Kireev D.M.
THE ANALYSIS OF THE MATERIAL SURFACE BIODEGRADATION IN THE PETROCHEMICAL PLANT COOLING WATER SYSTEM

The metal equipment at the enterprises of the petrochemical industry is operated under the conditions of interaction with the aquatic environment and, as a result, is subject to corrosive destruction. Microorganisms contained in the circulating water may accumulate on the surface of the metal and cause its biodegradation. To study the mechanisms of bio deterioration of materials under the conditions of a petrochemical plant, steel samples were exposed to exposure to circulating cooling water for different periods of time. The surface of the samples was investigated using confocal scanning laser microscopy and scanning electron microscopy. The products of interaction with circulating water found on the metal surface are represented by iron oxides, insoluble calcium salts, particles of coke, and also microorganisms and products of their vital activity. Microorganisms are identified as diatoms with a silicon shell and emit oxygen in the presence of daylight. It is known that silicon and carbon create with the metal of the pipeline and the equipment of the water-circulation cycle galvano couple and increase the corrosion rate. At the same time, the presence of oxygen on the metal surface, the concentration of which exceeds many times the concentration of oxygen in the volume of water, also leads to a significant increase in the rate of its corrosion. To reduce the intensity of corrosion damage to the material of the equipment of the petrochemical plant, the following recommendations were proposed: determination of the source of fine carbon discharged into the circulating water and its elimination; the use of reagents for the treatment of recycled water, preventing the growth of algae; the exclusion of sunlight in the circulating water in order to level the release of oxygen by the algae on the metal surface.

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