Crystal growth (C30)

C   Chemistry; metallurgy(312744)
C30            Crystal growth(2071)

ethod for producing thin nanodiamond film on glass substrate // 2614330
FIELD: chemistry.SUBSTANCE: thin nanodiamond film is obtained on a glass substrate by spraying the target material by a pulsed laser in a vacuum. The target is represented by detonation nanodiamond tablets, and the pulsed laser radiation source is represented by the laser with a wavelength of 1064 nm of a series of 13 to 20 pulses, with a pulse energy from 3.8 to 5.8 J and a duration from 1 to 1.5 ms. The process is accompanied by dispersing the detonation nanodiamond conglomerates up to individual nanocrystals and purification from impurities in the process of high-energy laser pulse impact. The resulting film is a two-dimensional polycrystalline nanodiamond aggregate.EFFECT: obtaining thin-film hardening coatings and creating nanostructured materials.9 dwg, 2 tbl, 5 ex

ethod for producing alloyed yttrium aluminium garnet // 2613994
FIELD: chemistry.SUBSTANCE: method is performed by dispersing the solid aluminium yttrium oxide derivative in nitrate aqueous solutions of alloying elements salts, and the subsequent treatment with the final product extraction. Wherein the initial yttrium aluminium derivative is represented by the product previously obtained by co-precipitation of aluminium and yttrium from the nitrate aqueous solutions. The resulting precipitation product is afterwards subjected to filtration and washing with deionized water. Thereafter, the extracted product is dispersed by the ultrasonic influence in the solution of the alloying elements selected from the group of alkali and alkaline earth metals and the elements of the 3d group, the resulting pulp is dried with constant stirring, the dried product is ground and calcined at 1200°C to 1600°C.EFFECT: invention allows to obtain yttrium aluminium garnet with the uniform distribution of alloying elements.3 cl, 4 dwg, 3 tbl, 4 ex
Polycrystalline synthetic jewelry material (versions) and method of its production // 2613520
FIELD: chemistry.SUBSTANCE: creating a polycrystalline jewelry material from coloured transparent or translucent oxide ceramics with dopants is proposed. The material consists of oxidic compounds which are represented by yttrium-aluminium garnet or magnesium aluminium spinel, for dying which ions of transition and rare earth metals: zinc, iron, vanadium, chromium, manganese, nickel, cobalt, titanium, neodymium, europium, terbium, ytterbium, holmium, erbium, thulium - are used. The method of manufacturing transparent or translucent ceramic comprises the stages of obtaining a powder mixture and annealing the components, hot uniaxial/cold isostatic pressing, hot isostatic pressing and heat treatment.EFFECT: wider colour range of samples and possibility of obtaining colour effects caused by the activator concentration variable as per the pattern or the crystalline phases are achieved, the cost of goods is much less in comparison with the use of single-crystal material.5 cl, 4 tbl, 2 ex
Inorganic single-crystal scintillator // 2613057
FIELD: chemistry.SUBSTANCE: invention relates to novel crystalline inorganic scintillation materials based on lanthanum bromide alloyed with cerium, and can be used for registration of ionizing radiation - gamma rays, X-rays, cosmic rays, elementary particles in fundamental physics, engineering and medicine. The inorganic single-crystal scintillator has the composition of La(1-m)CemBr(3-2k)Ok, where m is the mole fraction of cerium replacing La, more than 0, but less than or equal to 1; k - the mole fraction of oxygen replacing bromine, within the range from 1.5⋅10-4 to 8⋅10-4.EFFECT: increased mechanical strength of the crystal scintillator, in particular with a diameter of 15 mm and more, while preserving the high scintillation performances.1 tbl, 8 ex
ethod of producing copper-containing nano-catalysts with developed surface // 2611620
FIELD: technological processes.SUBSTANCE: invention relates to a method of producing copper-containing nano-catalysts with developed surface, which involves, that first from an electrolyte solution onto a metal carrier by electrodeposition copper is applied, then the carrier with the applied active metal is subjected to thermal processing. Electrodeposition process is performed in such a way, for to grow on a metal substrate with a heat conductivity coefficient less than 20 W/(m⋅K) a monolayer of icosahedral small particles of copper with micron sizes from 5 to 15 mcm and having 6 axes of symmetry of the 5th order, or layers of microcrystals with disclination type defects in the crystal lattice, then they are annealed in air atmosphere at the temperature of 300–400 °C and maintained for 4 hours till the small particles form a developed surface in the form of nanowhiskers or at the temperatures of 500–600 °C and maintained for 2–3 hours till the small particles form a developed surface in the form of nanopores, or inner cavities, or a corrugated relief.EFFECT: technical result is producing a nano-catalyst with high specific surface, good adhesion to a carrier, high mechanical strength and low hydrodynamic resistance.3 cl, 8 dwg

ethod for applying mark onto surface of diamond or cut diamond to determine its authenticity // 2611232
FIELD: security.SUBSTANCE: invention relates to a method of authenticating an article in the form of a diamond or a cut diamond. Identification mark invisible with the naked eye is applied onto a diamond or a cut diamond by exposure to a laser radiation with a wavelength exceeding 500 nm with simultaneous affecting by ultrasound using a tool located on the section surface. After that saved are at least two interference images of the article identification mark by means of a probing radiation with waves of different lengths together with data on location of a certain section of the article and an angle of incidence of the probing radiation. Determination of authenticity and correspondence to the saved values is carried out by directing the probing radiation onto the said section to create at least two interference images of the identification mark, which then are compared with the saved interference images, matching of which denotes the mark authenticity.EFFECT: technical result is ensuring uniqueness of the mark, protection from counterfeiting and reliable identification during authentication.4 cl, 2 dwg, 2 ex

ethod of impact compression of bodies with low density, apparatus and reactor for realising said method // 2610865
FIELD: physics.SUBSTANCE: invention relates to the field of high dynamic pressures and temperatures generation and may be used for chemical reactions, changes in the crystal structure of solids under high pressure and temperature, in particular for producing artificial diamonds (diamond powder), to compress the DT-ice to obtain a neutron source for inertial confinement fusion. The appartus for impact compression process of low density bodies contains the appartus shell 2 and a compressible body 1, installed at the front part of the apparatus shell. The hollow cylinder 5 can be mounted at the apparatus shell, the tail of which may joins a thin-walled hollow cylinder 7 with bar 9. The reactor for the execution of low density bodies impact compression consists of the reactor chamber and two accelerating devices for the apparatuses (cannons), looking toward each other. Inside the reactor chamber a porous layer of a porous metal is installed . The foam metal , tightly packed layer of thin-walled metal tubes, thin-walled boxes layers or cells can be used instead of a porous metal. The summary of the impact compression process of low-density bodies consists of axial compression of each compressed body by solid rear portion of the apparatus shell at frontal collision of two identical apparatuses in the reactor chamber. Thus, there is also impact compression by impact wave and the interference can be used, as well as focusing of reflected from the compressed bodies separation borders and apparatus shells of the impact waves. Also it can be carried out the radial compression of compressible bodies, converging towards the axis of apparatuses by circular liquid or plasma flow, obtained as a result of collision of two hollow cylinders. The interference of two impact waves can be used, resulting from the impact of bars at rear parts of the apparatus shells.EFFECT: invention allows to increase the final compression , pressure and temperature ratio, while the dynamic compression of low density bodies.13 cl, 17 dwg
ethod of producing crystals of thallium halide // 2610501
FIELD: technological processes.SUBSTANCE: invention relates to the production of materials, which are transparent in the infrared spectral region that can be used for manufacturing optical elements, that are transparent in the wavelength range from 0.4 to 25 microns; production of uncooled detectors c- and g-radiation for nuclear physics methods of diagnosis and monitoring, as well as the manufacture of optical fibers IR. A process for producing crystals of thallium halide for the infrared optics involves the synthesis of thallium halide reacting molten metal thallium, taken in excess, with the pairs of halogen in a vacuum, at a temperature at 10-30°C below the melting temperature of the resulting halide of thallium, which is carried out in a horizontally mounted container, made in two containers connected by a constriction of the hollow axis and rotating around its longitudinal axis at a speed of 120-150 rev/min, the separation of the excess metal from the ingot synthesized thallium halide, thallium halide purification obtained by vacuum distillation and melt crystallization directly followed by growing crystal.EFFECT: simplification of the process of crystal growth, and improvement of their optical quality.2 dwg, 2 ex

Device for preparation of single crystals of high-melting fluorides // 2608891
FIELD: chemistry.SUBSTANCE: invention relates to devices for preparation of single crystals of high-melting fluorides of horizontal directional crystallization from melt. Device comprises vacuum chamber 1 accommodating heat unit 2, consisting of coal-graphite heat-insulating modules 3, top 4 and bottom 5 heaters and heat shields 15, graphite container 6 with charge of material to be crystallised, installed with possibility of moving into a vacuum chamber 1, inert gas supply nozzles 10 and evacuation system and/or pumping of gaseous products 9, inspection window 11, wherein upper flat belt L-shaped heater 4 and bottom belt U-shaped heater of inverted shape 5 are made in form of graphite mono-blocks integrated with buses, on one side fixed with water-cooled current leads of vacuum chamber by means of detachable connection.EFFECT: simplified and improved manufacturability and reliability of heating assembly, including by eliminating effect of thermal expansions on heaters.3 cl, 2 dwg
ethod for synthesis of semiconductor nanoparticles // 2607405
FIELD: chemistry.SUBSTANCE: invention relates to colloidal chemistry and nanotechnology. Method comprises synthesis of nanocrystals of precursors containing chalcogen and a group II or IV metal, in presence of a solvent at room temperature using a "double drop method", for which said precursors are introduced simultaneously in droplets while stirring. Solvent used is an ionic liquid or a mixture of ionic liquids combined with one or more low-boiling organic solvents. Reaction mixture containing a nucleus of semiconductor quantum dots is exposed to UV light and treated with ultrasound. Nanoparticles of group II or IV metal chalcogenides are obtained with dispersion medium size of not more than 10 %, having high photostability and aggregative stability, capable of being dispersed in both polar and nonpolar solvents without additional treatment steps. Toxic solvents are not used during synthesis.EFFECT: invention can be used in production of luminescent materials, superminiature light-emitting diodes, white light sources, including transistors, nonlinear optical devices, photosensitive and photovoltaic devices.1 cl, 8 dwg, 11 ex

Complex lithium-lanthanum hafnate as luminescent material for conversion of monochromatic laser radiation and method for production thereof // 2606229
FIELD: chemistry.SUBSTANCE: invention relates to novel compounds of sensitised phosphors based on inorganic crystalline compounds, specifically to complex lithium-lanthanum hafnate composition Li7La3-x-y-z-nNdxHoyErzDynHf2O12, where x=2.5⋅10-2-1⋅10-1, y=1.6⋅10-7-4.7⋅10-7, z=1.5⋅10-6, n=1.2⋅10-6-4.7⋅10-6. Also disclosed is a method for production thereof.EFFECT: obtained composition is used as luminescent material for conversion of monochromatic laser radiation at wave length 808 nm into a series of emission lines 2–2,3 mcm, 2,5–2,9 mcm, 3,1–3,35 mcm.2 cl, 3 dwg, 3 ex

ethod of producing monocrystalline sic // 2603159
FIELD: chemistry.SUBSTANCE: invention relates to technology of producing monocrystalline SiC - wide-band gap semiconductor material, used for making integrated microcircuits. Method involves sublimation of SiC source 6 on inoculating plate 5 of monocrystalline SiC, fixed on cover 3 of a growth cell inside a cylindrical channel, formed in a growth cell, when source of SiC 6 is placed in cavity, formed by walls of growth cell, cylindrical channel and bottom 4 of growth cell, and passage of vapour phase of SiC source through wall of cylindrical channel, wherein growth cell is made of multiple, arranged in series one above another, sections 1 for arrangement of SiC source 6 and section 2 for forming ingot of monocrystalline SiC, in form of hollow graphite cylinder, on which there is cover 3 of growth cell with inoculating plate 5 of monocrystalline SiC, and each of sections 2 for arrangement of SiC source 6 is composed of two cylinders, located coaxially one inside another with radial clearance, inside of which lower edges of cylinders are tightly connected to bottom to form circular chamber for placement of SiC source 6 and inner cylindrical channel of section, wherein height of outer cylinder exceeds height of inner cylinder, and cylindrical channel of growth cell is formed, coaxially in series while placing section 1 for placement of SiC source 6 and section 2 for forming ingot of monocrystalline SiC 4 at bottom of growth cell. Furthermore, costs of carrying out method are reduced due to possibility of repeated use of growth cell by replacing separate degraded sections of growth cell with new ones.EFFECT: invention increases growth rate of ingot of monocrystalline SiC without deterioration of quality, which increases output of ingots of monocrystalline SiC per unit time.1 cl, 2 dwg, 1 tbl

ethod of producing vanadium dioxide nanoparticles // 2602896
FIELD: chemistry.SUBSTANCE: invention can be used in making thermochromic material, cathode material for lithium current sources, thermistors, thermal relays, switching elements. To obtain vanadium dioxide nanoparticles of monoclinic crystal system, method includes hydrothermal treatment of a mixture of ammonium metavanadate NH4VO3 and an organic acid and subsequent annealing of obtained product in a vacuum or inert atmosphere. Organic acid used is citric acid. Hydrothermal treatment is carried out at pH 4.0-5.5 and temperature of 180-220 °C for 2-20 minutes. Annealing of product is performed at temperature 350-370 °C for 5-60 minutes.EFFECT: invention enables to lower temperature and duration in production of vanadium dioxide of monoclinic crystal system, obtain particles with morphology of corrugated nanoplates.1 cl, 2 dwg, 4 ex

ethod of obtaining epitaxial layers of cdxhg(1-x)te of p-type of conductivity // 2602123
FIELD: electricity.SUBSTANCE: invention relates to materials of electronic equipment, namely to methods of obtaining epitaxial layers of semiconductor solid solutions of CdxHg1-xTe for making on their basis photovoltaic infrared radiation receivers. Method of obtaining epitaxial layers of CdxHg1-xTe of p-type conductivity involves growing an epitaxial layer of CdxHg1-xTe with a chemical composition within the range from x=0.19 to x=0.33 of molar ratio of cadmium telluride by liquid-phase epitaxy in a sealed quartz ampoule from a melt-solution based on tellurium at the temperature of 500÷515 °C and in situ annealing the epitaxial layer in vapors of charge, from which it was grown, first at the temperature of 350÷370 °C during 1÷2 hours, and then at the temperature of 200÷240 °C during 20÷24 hours. Technical result of the invention is reproducible obtaining the epitaxial layers of CdxHg1-xTe of p-type of conductivity with the concentration of charge carriers of (0.5÷2.0)×1016 cm-3 at 77K with high values of mobility of the charge carriers and uniform distribution of electrophysical characteristics throughout the thickness of the epitaxial layer, as well as reduced time for production of the epitaxial layers.EFFECT: proposed is a method of obtaining epitaxial layers of semiconductor solid solutions of CdxHg1-xTe for making on their basis photovoltaic infrared radiation receivers.1 cl, 1 tbl

ethod for growing monocrystals of substances with density exceeding density of their melt // 2600381
FIELD: manufacturing technology.SUBSTANCE: invention relates to growing monocrystals from a liquid melt using Czochralski's method. Growing a crystal with radius r is first performed using the Czochralski's method by drawing from fixed pot with radius R1, so that where ρhd - density of the crystal, ρl - is density of the melt. Produced crystal is tore off the melt and cooled to room temperature in a growth chamber. Then, the growth chamber is opened, the pot is removed from the heater replaced with a pot of smaller radius R2, such that thereafter the chamber is closed, temperature is raised to melting point, crystal is lowered to contact with the melt and the crystal is again grown by its permanent downward movement.EFFECT: technical result is improved structural perfection of grown crystals due to reduction of residual mechanical stresses and reduction of density of dislocations.1 cl, 6 dwg, 2 ex

Germanium monocrystals-based method for producing shaped articles // 2600380
FIELD: optics.SUBSTANCE: invention relates to technology of producing optical articles made from germanium by growing germanium monocrystals from the melt in the form of shaped articles in the form of convex-concave pieces, which can be used after processing for making the lenses of the infrared range. Germanium monocrystals are grown on the inoculating crystal using a vertical shaping element 1 placed into crucible 2, having holes 6 in the point where its lower part adjoins crucible 2 to remove the excess melt formed during germanium crystallization, horizontal upper and lower shaping elements are placed in the grooves of vertical shaping element 1 with diameter d, said upper and lower shaping elements have central holes, elements 3 of convex-concave shape with diameters, d1 and d2, respectively, at that, d2> d1> d. Grown monocrystal is shaped as a lens piece due to shaping elements.EFFECT: invention enables serial producing germanium monocrystals (including large-sized ones) with different section shape with minimum material consumption.1 cl, 1 dwg, 2 ex

Optical medium based on cadmium-caesium halide crystal cscdbr3, containing impurity of univalent bismuth ions capable of broadband photoluminescence in near infrared range, and production method thereof (versions) // 2600359
FIELD: chemistry.SUBSTANCE: invention relates to optical media based on crystalline halides and can be used in optical communication systems as broadband amplifiers and lasers. Optical medium contains low-valent bismuth ions as only optically active centre, is capable of broadband luminescence in near infrared range, is a crystalline phase of caesiu-cadmium bromide CsCdBr3, containing an isomorphic admixture of univalent bismuth ions Bi+ in amount of 0.1 atm% to 3 atm%, and luminesces in range of 900-1,200 nm when excited with radiation with wavelength in range of 570-700 nm. Disclosed are two versions of a method of producing an optical medium. First version involves preparation of charge by mixing CsBr, CdBr2 and BiBr3 or CsCdBr3, CdBr2 and BiBr3, adding to charge bismuth metal, heating obtained mixture placed in a quartz container, in a vacuum to temperature of 450-500 °C until complete melting, slow cooling of melt to spontaneous crystallisation and separation of monocrystals from produced polycrystalline structure. Second version involves preparation of charge by mixing CsBr, CdBr2 and BiBr3 or CsCdBr3, CdBr2 and BiBr3, adding to charge bismuth metal, placing mixture in a quartz container in a vertical Bridgman-Stockbarger furnace until formation of a monocrystalline sample of optical medium. Disclosed optical medium is not hygroscopic, possesses stable luminescence in near infrared range, specifically in range of 900-1,200 nm when excited with radiation with wavelength in range of 570-700 nm.EFFECT: method of producing bromide CsCdBr3 is quite simple technologically and enables to grow quality crystals of required dimensions.4 cl, 2 dwg, 4 ex

ethod and device for refining technical silicon // 2600055
FIELD: technological processes.SUBSTANCE: invention relates to production of technical silicium in ore-thermal furnaces and its further refinement. Method of refining technical silicon is implemented by directed crystallization, herewith the silicon melt is cooled down to 1,420 °C, immersed for 3-30 sec with metal crystallizing molds with the initial temperature of approximately 150-200 °C, impurities of metals in form of intermetallic compounds and solid solutions with silicon are extracted on the molds surfaces, after which the molds together with the impurities are removed from the melt and moved into a superheated flux for draining of silicon enriched with the impurities. Molds are made in the form of solids of revolution - balls, cones or cylinders. Device for implementation of this method comprises a mass exchanger with molten silicon and a settler with overheated flux for accumulation of silicon with increased content of impurities. Solids of revolution can be equipped with pins to increase the surfaces of crystallization.EFFECT: invention ensures production of high-quality and cheap raw material with low content of impurities for further mass production of ultrapure silicon (SoG-Si).3 cl, 2 dwg

Device for growing monocrystals of fluorides and synthesis method thereof // 2599672
FIELD: chemistry.SUBSTANCE: invention relates to production of monocrystals of fluorides from melt for use in optics. Device for growing monocrystals of fluorides 10 from melt 9 by drawing down comprises crucible-heater 5 made from graphite in form of vertically installed hollow thin-walled cylinder, equipped in lower part with cover 6 made from graphite with a hole of an arbitrary shape, repeating required section of grown crystal 10, wherein cross section of hole in cover is not more than 1.5 mm, its length is 0.1-1.0 mm, cover 6 is detachable with possibility of repeated mounting-dismantling and crucible-heater 5 is equipped with electric lines 7, 8, made of refractory material, for example graphite.EFFECT: invention enables to grow monocrystals of fluorides of high optical quality in form of fibres and rods with rectangular or round section with typical dimensions from 0,2 to 1,5 mm.1 cl, 7 dwg
ethod of alloying silicon // 2597389
FIELD: chemistry.SUBSTANCE: invention relates to equipment, related to processes of ion-plasma alloying of semiconductors and can be used in making solar cells, semiconductor instruments and integrated microcircuits based on silicon. Doping technique of silicon consists in that silicon plate is treated in glow discharge of inert gases, non-doped dopant source used is heavily doped electrode in form of plate made of heterogeneous silicon alloy with phosphorus or boron, and alloying is carried out at alternate polarity of voltage pulses supplied to electrodes. Plasma alloying can be carried out without special safety measures and exclusion of expensive highly toxic fire and explosion hazardous gases, which simplifies process and reduces costs. Before ion-plasma treatment resistance silicon plate resistance is equal to 10 Ohm, after processing it decreases to 3 Ohm that testifies to improvement of technical and economic parameters of silicon alloying.EFFECT: alloying.1 cl
ethod for production of solid disperse system with silicon dioxide // 2595846
FIELD: pharmaceutics.SUBSTANCE: invention relates to medicinal agents, concerns preparation of dosage forms on basis of silicon dioxide. Task is solved by that mixer is filled mesoporous silicon dioxide, feeding into reactor an absorbable solution or melt of medicinal and auxiliary substances and intensely stirring for 5-7 minutes. Bulk product is formed with virtually 100 % yield and absence of losses. Flow rate of initial powder, as well as their compositions with auxiliary substances are assessed by rate of precipitation of powder or granules using a vibration funnel of serial device VP-12A with diameter of outlet hole 12 mm.EFFECT: frequency and amplitude of vibration of vibration funnel is 50 Hz and 0, 08 mm, respectively.1 cl, 5 ex, 2 tbl

ethod of producing wollastonite // 2595682
FIELD: chemistry.SUBSTANCE: invention relates to processing of calcium- and silicon-containing industrial wastes from boron production (borogypsum) and can be used in production of needle wollastonite for use in non-ferrous metallurgy, in tyre, asbestos-cement and paint industry, in production of ceramics. Wollastonite is produced by hydrothermal action on calcium- and silica-containing technogenic raw material with alkali metal hydroxide, followed by separation, drying and thermal treatment of formed precipitate with calcium hydromonosilicate, wherein calcium- and silica-containing material used is borogypsum, alkali metal hydroxide is added in stoichiometric amount based on reaction equation of formation of calcium hydromonosilicate in concentration, providing ratio of solid and liquid phases S:L=1:(7-10), wherein reaction is carried out in an autoclave at temperature of 210-225 °C and pressure of 20-23 atm, separated calcium hydromonosilicate is washed with water at 60-70 °C and dried at 80-90 °C for 4 hours, thermal treatment is carried out at 850-1,000 °C for 1-2 hours.EFFECT: technical result is simplification and high environmental safety of method with simultaneous reduction of cost due to minimisation of labour input and costs for preparation of initial components.1 cl, 8 dwg, 2 ex

Obtained by chemical deposition from vapor phase monocrystalline synthetic diamond materials, which have uniform colour // 2595671
FIELD: technological processes.SUBSTANCE: invention relates to production of coloured diamonds, which can be used in optics and for jewelry purposes. Monocrystalline CVD-synthetic diamond material comprises multiple layers, which includes at least two groups of layers differ in their defects composition and colour, wherein type of defects, concentration of defects and thickness of layers for each of said at least two layers are such that if coloured monocrystalline CVD diamond material is processed into diamond with round brilliant cut, containing platform and culet and having depth from platform to culet of more than 1 mm, then diamond with round brilliant cut has uniform colour when viewed with naked eye of person in standard surrounding observation conditions in, at least, direction through platform to culet; said, at least, two groups of layers contain first group of layers containing alloying admixture of boron in concentration sufficient for producing blue colour, and second group of layers containing lower concentration of alloying admixture of boron, first group of layers contains not compensated dopant of boron in concentration of not less than 0.01 ppm and not more than 5.00 ppm, and second group of layers contains dopant of insulating replacement nitrogen in concentration of not less than 0.01 ppm and not more than 5 ppm, wherein visibility quality indicator (FM) of individual layers is not more than 0.15 and is calculated as product of: FM = thickness (mm) of layers for first set of layers × thickness (mm) layers for second set of layers × concentration (ppm) of solid-state boron in first group of layers × depth (mm) of round brilliant cut.EFFECT: invention enables to obtain uniform blue colour diamonds with high growth rate.14 cl, 6 dwg

ethod and device for production of separate nitrides crystals of iii group // 2593868
FIELD: technological processes. SUBSTANCE: invention relates to production of separate crystals nitrides of Group III elements for electronic and optoelectronic applications. Method involves stages of growth of first layer of nitrides of Group III elements on foreign substrate, treatment first layer of nitrides of Group III elements with laser, growth of second layer of nitrides of Group III elements on first layer of nitrides of Group III elements, separation by laser peeling of second layer of nitrides of Group III elements from substrate, wherein laser treatment of first layer is made inside reactor at temperature of ±50 °C from growth temperature, laser treatment of first layer is selected, at least one of following: cutting, drilling or etching to form grooves, holes or other cavities in first layer and create lower voltage areas between them, stage of separation with help of laser peeling of second layer of nitrides of Group III elements from substrate is made inside reactor at temperature of ±50 °C from growth temperature. Method is realised in reactor containing first zone 8 for epitaxial growth of layers 2.5 nitrides of Group III elements by CVD on foreign substrate 1, second zone 9 for laser processing, which includes laser processing 11 system with front side of layer 2 nitrides of Group III elements to create stress relief area, which is selected, at least from one of following: laser cutting, drilling or etching, and layer 5 peeling system 10 of nitrides of Group III elements from substrate by laser beam, penetrating to layer from back side of substrate. EFFECT: production of crystals in form of plates with low voltages and low density of defects. 2 cl, 2 dwg

Novel cocrystals of agomelatine, synthesis method thereof and pharmaceutical compositions containing same // 2593749
FIELD: chemistry. SUBSTANCE: invention relates to agomelatine co-crystall, which is characterised by that it consists of agomelatine, or N-[2-(7-methoxy-1-naphtyl)ethyl]acetamide of formula (I), and organic acid, which is in solid state at ambient temperature, which is selected from a steam-hydroxybenzoic acid, citric acid, oxalic acid, Gallic acid, maleic acid, malonic acid, glutaric acid, glycolic acid or ketoglutaric acid. Agomelatine co-crystall and organic acid are obtained by mixing two components in organic solvent in desirable proportions: 1 agomelatine equivalent at 0.25-4 mol equivalent of organic acid, than obtained solution is stirred and optionally is heated at temperature not exceeding boiling point of selected solvent, then mixture is cooled while stirring, and deposited co-crystall naturally or precipitates after absorption in second solvent, obtained precipitate is filtered and dried. Also co-crystall is obtained by combined grinding of two components. Also co-crystall is obtained by mixing two components in organic or aqueous-organic solvent, followed by freezing and drying at very low temperature. Alternative method of preparing co-crystall involves mixing powders agomelatine and said acid in mixer, and then mixture is extruded by extrusion in twin-screw mixers without matrix to obtain solid granulated product directly at extrusion device outlet. Agomelatine co-crystall and organic acid are applicable for preparing drugs for treating disturbed melatonin aergic system. EFFECT: technical result is agomelatine co-crystalls permitting to modify rate of active ingredient dissolution. 19 cl, 13 ex

Diamond surface treatment // 2593641
FIELD: electronics. SUBSTANCE: invention relates to methods of processing diamond surface for its use in microwave electronic equipment. Method involves arrangement in one plane of initial surface of diamond and metal surface of steel, providing direct contact of said surfaces, thermal treatment of initial diamond surface at given depth to preset final diamond surface, wherein providing of heating of said surfaces in inert medium, at specified speed, near temperature of formation of eutectic alloy of iron-carbon, holding at this temperature and natural cooling, wherein metal surface of steel are taken with carbon content of 3.9-4.1 wt.%, with surface finish class on side of contact of said surfaces of not less than 14, contact of said surfaces is performed over entire surface or locally according to specified end surface of diamond, heating said surfaces is performed at 1090-1135 °C, during heating of primary diamond surface and metal surface of steel and holding their displacement in contact plane is performed relative to each other in cycles, wherein holding at said temperature is performed during time (thold., s), movement of initial surface of diamond and metal surface of steel relative to each other is carried out at rate of displacement (vdisp, mm/s) and amount of cycles of displacement (n), which values are determined from corresponding expressions. EFFECT: technical result is increase of quality of treatment due to reduced surface roughness of diamond. 7 cl, 1 tbl, 21 ex

ethod of producing silicon // 2592629
FIELD: metallurgy. SUBSTANCE: invention relates to processing of siliceous rocks in production of semiconductor materials, which can be used for making solar collectors and elements of electronic equipment. Method involves breaking down and processing siliceous rock to produce silica powder, irradiation, cleaning and reduction to silicon, wherein after irradiation powdered silica is subjected to tempering at 950-1,000 °C in a protective or reducing medium. EFFECT: invention increases depth of decomposition of ore components by affecting kinetics of decomposition of raw material at early stage of production of silicon, reduces concentration of impurities and power consumption when grinding. 1 cl, 4 tbl, 4 ex

onocrystalline material for disc laser // 2591257
FIELD: optics.SUBSTANCE: invention relates to laser engineering and concerns monocrystalline material for disc lasers. Monocrystalline material is based on a yttrium aluminium garnet, activated by ytterbium ions. Initial components are taken in accordance with the structural formula Yba(z):Y3-a(z)Al5O12, where - function of concentration profile change, z - axis of direction of forming the crystal concentration profile, 0<z<1.2.EFFECT: providing smoothed distribution of heat field, the absence of thermal lens inside the active element and increase of maximum size of the generated volume in the active element.1 cl, 3 dwg, 1 tbl

onocrystalline material with heterogeneous distribution of optical impurities for active laser element // 2591253
FIELD: optics.SUBSTANCE: invention relates to laser engineering and concerns monocrystalline material with heterogeneous distribution of optical impurities according to a given law along the active laser element with the following structural formula: wherewhere z is a spatial coordinate directed along the length of the crystal and determining the change of Erbium and ytterbium ions concentration profile in the reference system, originating in the inlet face of the active element and having a value from 0 to 1 cm.EFFECT: high efficiency of lengthwise pumping of an active laser element.1 cl, 5 dwg, 1 tbl

Crystalline colloidal arrays with high reflecting capacity, including radiation-absorbing particles // 2591158
FIELD: optics.SUBSTANCE: invention relates to crystalline colloidal arrays used as materials scattering radiation. Described is a radiation reflecting and absorbing composite composition containing a plurality of colloidal crystals or units of colloidal crystals, wherein each said crystal contains radiation reflecting particles in form of a colloidal mass and radiation absorbing particles dispersed in crystals. Composition scatters radiation in one band substantially in all directions and absorbs radiation in other band. Method of producing radiation scattering composition is performed by preparing a dispersion of charged particles in form of periodic arrays to obtain a plurality of colloidal crystals, in which are randomly distributed radiation absorbing particles. Described also is a reflecting coating composition containing composite composition and a film-forming composition.EFFECT: reflection in a wide wavelength range, which enables to endow coating composition, in particular coating, a white colour appearance or masking properties.19 cl, 9 dwg, 18 ex

ethod of growing monocrystal of barium-sodium meta-fluoroborate ba2na3(b3o6)2f // 2591156
FIELD: chemistry.SUBSTANCE: invention relates to technology of growing monocrystals of barium-sodium meta-fluoroborate Ba2Na3(B3O6)2F for use in terahertz range from 0.3 THz to 1 THz as wave plates, polarisers, as well as in air terahertz photonics. Monocrystal of Ba2Na3(B3O6)2F is grown from high-temperature solution by lowering temperature of solution-melt on a nucleating agent that is retractable and rotating oriented along an optical axis. Solvent used is sodium-barium borate NaBaBO3. Crystallisation is performed in a Ba2Na3(B3O6)2F-NaBaBO3 system at ratio Ba2Na3(B3O6)2F:NaBaBO3, equal to 60-80:20-40 mol%. Barium-sodium meta-fluoroborate Ba2Na3(B3O6)2(F) has in range from 0.3 THz to 1 THz high birefringence (Δn/n = 0.16) and low absorption (less than 10 cm-1).EFFECT: technical result consists in reproducible production of monocrystals of Ba2Na3(B3O6)2F of optical quality, containing no visible inclusions with coefficient of output - 3 75/100-3 95/100 g/(kg·deg).1 cl, 2 dwg, 1 ex

ethod for deposition of monocrystalline tungsten-based alloys // 2590568
FIELD: technological processes.SUBSTANCE: invention relates to production of tungsten alloyed with niobium or tantalum, and can be used in electrovacuum instrument making, electronics. Method for deposition of monocrystalline tungsten-based alloys by chemical transport reactions on tubular monocrystalline molybdenum substrate installed inside crude tungsten pipe, involves heating substrate by means of internal heater to temperature of alloy deposition of 1,500÷1,800°C and feeding pentachloride alloying metal in volume of reaction vessel at substrate temperature below deposition temperature of alloy (500÷1,000°C), wherein temperature in deposition zone during entire process of alloy deposition is kept constant within temperature range of 1,500÷1,800°C by gradually raising temperature of substrate as thickness of deposited alloy increases.EFFECT: invention enables to obtain chemically uniform thickness of alloy due to invariance of gas phase in zone of decomposition of halides in time.4 cl, 5 dwg, 3 ex

ethod for thermal synthesis of nanosize particles of yttrium aluminium garnet in medium of organic solvents // 2588227
FIELD: technological processes.SUBSTANCE: invention relates to technology of producing nano powder yttrium aluminium garnet, which is used as initial powder oxide ceramics, in dispersed state as filler or pigment or as starting powder for production of mono crystal or coating applied by plasma spraying. Method of thermal synthesis of nano size particles of yttrium aluminium garnet in medium of organic solvents is characterised by that mix of yttrium chloride, aluminium chloride and aluminium isopropylate in ratio 3:1:4 is subjected to heat treatment at intensive mixing in diphenyloxide, oleic acid, stearic acid or oleyl amine at temperature of 250-300 °C in argon atmosphere for 8 to 24 hours, after which formed precipitate is filtered at Buchner funnel and thoroughly washed with benzene. At that, synthesis temperature is reduced by 500-600 °C, which results in almost double reduction of power inputs for process of producing yttrium aluminium garnet.EFFECT: disclosed method enables to obtain monophase product of yttrium aluminium garnet.2 cl, 4 dwg, 1 tbl

ethod of producing ultrafine powder of silver and silver ultrafine powder obtained using said method // 2587446
FIELD: medicine.SUBSTANCE: invention relates to methods for obtaining powder material containing microparticles, and can be used in medicine as a bactericidal material, in chemistry for purification of drinking water; in production of catalysts; in chemical industry for protective coating of pipeline walls; in the chemical current sources. Method of producing ultrafine silver powder includes treatment of water solution of silver nitrate with reducing agent. As a reducing agent the aqueous solution of thiocarbonic acid (thiourea) and ammonium hydroxide is used taken in the following ratio: silver nitrate:thiocarbonic acid diamide (thiourea):ammonium hydroxide = 1:5÷10:0.01÷0.8. Obtained ultradisperse silver powder contains modified particles of star-like shape, having from 32 to 56 pyramidal and wedge-like beams with length of 40-50 microns with average size of the core 5-6 microns, the density of powder is equal to 0.4-0.8 g/cm3.EFFECT: technical result consists in obtaining of pure metal particles of silver, characterised with modified structure of surface morphology, simple efficient method using safe and ecologically pure substances.2 cl, 2 dwg, 2 ex

Chemical method of producing artificial diamonds // 2586140
FIELD: chemistry.SUBSTANCE: invention relates to inorganic synthesis of artificial diamonds of size of up to 150 mcm, which can be used in production of abrasive and diamond lubricants, drilling equipment. Synthesis of diamonds is carried out in molten metal matrix with direct reaction of carbon-containing additive contained in concentrations of 2 to 10 wt% in molten chlorides and/or fluorides of alkali metals, with molten metal, such as aluminium, zinc, magnesium, tin, lead, as well as their alloys for 1-5 hours at temperature of 700-900 °C in an air atmosphere and further cooling and/or thermal treatment, carbon-containing additive is represented by carbides of metals or non-metals or solid organic substances relating to classes of hydrocarbons or carbohydrates, or carboxylic acids.EFFECT: invention enables to obtain cubic nano- and micro-diamond at atmospheric pressure and low temperature without using complex processing equipment.1 cl, 18 dwg, 1 tbl, 7 ex

ethod of increasing size of diamonds // 2585634
FIELD: chemistry.SUBSTANCE: invention relates to production of synthetic diamonds and can be used as nuclear radiation detectors in fast particle counters, as well as in jewelry. Method involves depositing carbon on seed crystals of diamonds during their heating in vacuum, seed crystals pre-fixed on surface of a polished monocrystalline silicon plates coated with a layer of polyvinyl acetate, after which silicon plate is heated with electric potential shift 80 in vacuum, then methane is supplied at pressure 10-30 Torr and curing at a temperature of 1,170±20 °C with cyclic pumping of reaction products and feed fresh methane.EFFECT: technical result consists in significant increase of initial diamond crystals in group process over a considerably shorter process cycle.1 cl, 2 dwg, 1 ex

ethod of producing carbon films with boron-doped diamond // 2585311
FIELD: manufacturing technology.SUBSTANCE: invention relates to technology of thin-film materials and can be used in designing of passive and active elements of micro- and optoelectronic devices. Method of producing carbon films with diamond structure doped with boron, carried out by chemical deposition from gas phase onto carbon film placed in reactor substrate, alloying substance is boron in solid phase with density more than 95 % of theoretical value is placed outside zone of high-frequency discharge at distance from substrate, less than free pass length of boron atoms, and alloying of films process is carried out by spraying boron by autonomous source of laser radiation with power of 0.05-1.5 W/cm2.EFFECT: increased output of films with reproducible electrical parameters.3 cl, 2 dwg, 1 tbl
Polycrystalline diamond // 2581397
FIELD: chemistry.SUBSTANCE: invention relates to polycrystalline diamond for use in a variety of instruments. Polycrystalline diamond is characterized in that it comprises a sintered diamond grains having an average grain diameter of more than 50 nm and less than 2500 nm, the purity of 99 % or more and the grain diameter of D90, is (average grain diameter + average grain diameter of × 0.9) or less, wherein the polycrystalline diamond has a lamellar structure and has a hardness of 100 GPa or more.EFFECT: water jet nozzle cutter for engraving gravure scriber, cutting tool and scribing clip from such material ensures stable processing over a long period of time as compared with conventional tools comprising monocrystalline diamond and the sintered diamond compact containing metal binders.13 cl, 5 tbl, 62 ex

ethod of producing polycrystalline silicon and reactor for producing polycrystalline silicon // 2581090
FIELD: chemistry.SUBSTANCE: invention relates to production of polycrystalline silicon by depositing on silicon electrode wire using Siemens method. Method includes first stage with relatively low gas supply, last stage with relatively high gas supply and intermediate step where amount of supplied gas is increased from value of supply at first stage to supply at last step at supply of initial gas containing gaseous chlorosilanes and hydrogen gas, in reactor through inlet hole with nozzle, all three stages are carried out at reaction temperature of 900 °C to 1250 °C and under pressure of 0.3-0.9 MPa, velocity in inlet hole with nozzle head piece is 150 m/s or more at maximum feeding of initial gas at last step, and gas supply and temperature of silicon rod is controlled in accordance with following conditions of A-C depending on polycrystalline silicon rod diameter D, which varies during deposition reaction after its beginning: condition A (amount of supplied gaseous chlorosilanes): gaseous chlorosilanes are fed in amount of one third or less of maximum gaseous chlorosilanes feed until specified value D1 from 15 to 40 mm is achieved, supplied amount is increased gradually or in steps until maximum supply of gaseous in chlorosilane between when achieved value D1, and when will be achieved specified value D2 from 15 to 40 mm, which is more than D1, maximum gaseous chlorosilane feed kept after achievement of D2 value; condition B (amount of supplied gaseous hydrogen): gaseous hydrogen is supplied to concentration of gaseous chlorosilanes in initial gas is from 30 mol% to less than 40 mol% until value D1 is achieved, ratio of amount of fed hydrogen gas to amount of gaseous in chlorosilane increases gradually or in steps after value D1 is achieved, gaseous hydrogen is supplied to concentration of gaseous chlorosilanes in source gas makes from 15 mol% to less than 30 mol% after value D2 is achieved and condition C (silicon rod temperature): temperature is decreased as silicon rod diameter after value D2 is achieved.EFFECT: thus, rod of high-purity polycrystalline silicon without minor defects of "popcorn" type may be produced without reducing efficiency even in reaction system with high pressure, high load and high rate of reaction.5 cl, 2 dwg, 1 tbl, 6 ex

ethod of processing monocrystalline cvd-diamond and the obtained product // 2580916
FIELD: technological processes.SUBSTANCE: invention relates to processing monocrystalline CVD-diamond material. Described is a method for introducing NV-centres in monocrystalline CVD-diamond material. One stage of the method involves irradiating the diamond material, which contains a single replacing nitrogen Ns 0, for introducing isolated vacancies in the diamond material in the concentration 0.05-1 ppm. Other stage includes annealing irradiated diamond material at temperature of 700-900 °C to form NV-centres from at least some of the defects of single substituent nitrogen and introduced isolated vacancies.EFFECT: this processing of diamond material maximises obtaining of NV-centres, minimising other undesirable defects, which enables to use it in spintronic and associated with colour applications, in particular, for using in fancy pale-rose synthetic precious stones or coloured filters.16 cl, 7 dwg, 12 tbl

Process for production of synthetic monocrystalline diamond material // 2580743
FIELD: chemistry.SUBSTANCE: invention relates to process of synthesis of plurality of synthetic monocrystalline diamonds. Proposed method comprises forming multiple seed pads, each having plurality of inoculating diamond monocrystals attached to inert holder or embedded in it, loading of carbon source, metal catalyst and plurality of seed pads into capsule, wherein at least part of carbon source is located at distance less than 0.1 mm from inoculating diamond monocrystals, loading capsule into high pressure and temperature press (HPHT) and exposure of capsule to cycle of HPHT-growth for growth of monocrystalline diamond material on plurality of inoculating diamond monocrystals, wherein cycle HPHT-growth includes initiation HPHT-growth of monocrystalline diamond material on plurality of inoculating diamond monocrystals by increasing pressure and temperature, maintenance HPHT-growth of monocrystalline diamond material on plurality of inoculating diamond monocrystals by means of controlled pressure by controlling growth process and pressure and temperature maintenance and termination HPHT-growth of monocrystalline diamond material on plurality of inoculating diamond monocrystals by reducing pressure and temperature, plurality of inoculating diamond monocrystals are attached to inert holders or embedded therein during cycle of HPHT-growth.EFFECT: invention enables to obtain for cycle more coarse diamond crystals with uniform morphology.22 cl, 7 dwg

ethod of producing single-phase crystalline silicon-substituted hydroxyapatite // 2580728
FIELD: chemistry.SUBSTANCE: invention relates to a process of preparation of crystalline silicon-substituted hydroxyapatite (Si-HA), which can be used in orthopedics and dentistry. Si-HA is received by deposition method from extracellular fluid model solution by preparing a solution with the following composition: CaCl2 - 3.7424 g, MgCl2 - 0.6092 g, K2NRO4 - 2.8716 g, NaHCO3 - 4.5360 g, Na2SO4 - 0.0144 g, NaCl - 8,8784 g at pH 7.40±0.05, by adding to it of modified sodium silicate in a molar ratio of Ca/ (P + Si) 2.00÷2.50 in the shape of Na2SiO3, by letting it settle for 48 hours, by filtering, washing and drying at a temperature of 80±5 °C for 5 hours.EFFECT: invention allows to obtain a monophasic nanocrystalline (with an average crystal size of 6-7 1/10 nm) Si-HA having enhanced bioactivity in a medium that simulates the extracellular fluid of a human body.1 cl, 5 dwg, 3 tbl

ethod of connection and fixation of monocrystals (versions), device for method implementation and stack obtained using them // 2580127
FIELD: technological processes.SUBSTANCE: invention relates to mechanical methods of processing monocrystalline ingots. Method of connecting and fixing mono crystals involves the positioning of several mono crystals, their orientation in a certain way and fixation of mono crystals with each other by means of adhesive, whereupon pre-selection of the necessary number of monocrystalline ingots is carried out, and then carry out orientation of the ends of the selected ingots with required tolerance and removal of base pre-cut with the length of 18-20 mm, whereupon glue mono crystal ingots using device to connect and fix mono crystals as follows: apply adhesive material onto previously degreased end of the mono crystal ingot, mount ingot with preliminary base cut on the base plane 1 of the device while pressing the ingot with clean end against the fixed stop 4 and ingot generant to the surface of the side guard 2, mount next ingot with preliminary base cut on the base plane 1 of the device firmly against the end of the previous ingot, and rotating the knob 7 of the pressing screw 6, press ingots against each other by means of movable stop 5, repeat these operations until the stack of required length is obtained, maintain stack in the device until complete curing of the adhesive material using two-component, colorless epoxy rubber adhesive, and then carry out calibration of the stack to the desired diameter and detach the main base cut, control orientation of the base cut and perpendicularity of ends to the generate. Alternatively, the method of connection and fixation of monocrystals can be implemented without removal of preliminary base cut using device for applying general auxiliary line.EFFECT: simplified connection and fixation of monocrystals, reduced time costs, higher accuracy of alignment of crystallographic axes of monocrystal ingots.8 cl, 4 dwg, 1 tbl

Sintered body from alpha-alumina for producing sapphire single crystal // 2579596
FIELD: metallurgy.SUBSTANCE: invention relates to a technique for producing a sintered body from α-alumina as a raw material for further production of sapphire single crystals. Method comprises following steps: mixing 100 parts by weight α-alumina with 1-20 parts by weight α-alumina precursor to obtain a mixture, molding a compact from mixture and firing said compact to obtain a sintered body of α-alumina, wherein α-alumina has a specific surface area equal to 1-20 m2/g, a moisture content less than 0.5 %, purity of 99.99 wt.% or more and content of each of Si, Na, Ca, Fe, Cu and Mg, equal to 10 ppm or less, α-alumina precursor has a specific surface area of 50 m2/g or more, moisture content of 0.5 % or more, purity of 99.99 wt.% or more and content of each of Si, Na, Ca, Fe, Cu and Mg, equal to 10 ppm or less, at a pressing pressure of 20-400 MPa, firing is conducted at a temperature of 1,200-1,700 °C for 0.5-24 hours and rate of temperature rise of 30-500 °C/h. Invention enables to obtain a body having a relative density of 60 % or more, a closed porosity of 10 % or less, purity of 99.99 wt.% or more, content of each of Si, Na, Ca, Fe, Cu and Mg equal to 10 ppm or less, and volume of 1 cm3 or more.EFFECT: bodies with said characteristics have high mechanical strength and allow easy production of a high quality sapphire single crystal with less coloring and cracking and high volumetric efficiency.6 cl, 1 dwg, 4 tbl, 3 ex

Diamond surface treatment // 2579398
FIELD: processes.SUBSTANCE: method of treating the surface of the diamond includes positional relationship in one plane of the original surface of the diamond and the metal surfaces of steel, ensure direct contact of said surfaces, the heat treatment of the original surface of the diamond to a predetermined depth to provide the desired final surface of the diamond, thus providing for heating said surfaces to the temperature of formation of the eutectic iron alloy - carbon, soaking at this temperature and free cooling, and the metal surface of steel with a carbon content taking 3.9-4.1 wt. %, purity class-side surface of said contact surfaces is not less than 12, said contact surfaces is performed by their entire surface or locally according to predetermined final surface of the diamond, said heating surfaces is carried out in a nitrogen atmosphere or an inert gas at a temperature of 1090-1135°C, at a predetermined rate, holding at this temperature is performed for a time determined by the expression: tvyd=d/f(T,(Nes-Nc)), where d - the predetermined depth of thermal treatment of the original surface of the diamond, m, Nes - carbon content of the iron eutectic alloy - carbon of the original surface of the diamond and the metal surfaces of steel, by weight. %, Nc - carbon content of the metal surface of steel, by weight %, f(T,(Nes-Nc)) - function of the speed of the initial heat treatment of the diamond surface to a predetermined depth from the surface of said heating temperature and the difference in the carbon content of the iron eutectic alloy - carbon and the metallic surface of the steel.EFFECT: improving the quality of processing by reducing the surface roughness of the diamond.5 cl, 1 dwg, 1 tbl, 21 ex

ethod of producing cadmium tetraborate cdb4o7 // 2579390
FIELD: chemistry.SUBSTANCE: invention relates to production of polycrystalline borates, which can be used as a solid-state matrices for efficient luminophores. For producing cadmium tetraborate CdB4O7 by thermal treatment of initial components used are a mixture of CdO (31.03 wt%), H3BO3 (68.97 wt%). Process is carried out on air with stepped lifting temperature from 300-850°C for 250 hours.EFFECT: invention enables to obtain monophase polycrystalline cadmium tetraborate CdB4O7 without pelletisation of sample.1 cl, 1 dwg, 2 tbl, 1 ex

Production of thermoelectric materials based on bismuth and stibium tellurides // 2579389
FIELD: process engineering.SUBSTANCE: invention relates to production of thermoelectric materials based on bismuth and stibium tellurides. Claimed process consists in pretreatment of initial components by vacuum distillation, synthesis of initial components in evacuated ampoules at heating to melting and cooling. Crystals are grown by vertical zone recrystallisation with application of high-frequency heating. Note here that the crystals are grown in at least two passes at the rate of not over 2.5-3 cm/h. Said high-frequency heating is conducted in the frequency of 1.76 MHz at the temperature gradient of 200 K/cm. The crystals grown, powders are made with nanostructure not over 200 nm in size to allow anisotropy of properties of every particle. Then, pelletising, sintering and hot extrusion are conducted. Said crystals are grown simultaneously in 6-10 ampoules up to 1 m long. Sintering is executed in the vacuum furnace for a day at about 450 degrees. After extrusion, the specimens are cut mechanically and complex measurements are performed.EFFECT: higher strength, homogeneous properties, better thermoelectric characteristics.4 cl, 2 dwg, 3 tbl

ethod for producing superfine nanocrystalline lead tungstate // 2577581
FIELD: nanotechnology.SUBSTANCE: invention relates to production of nanocrystalline powders of chemical compounds and can be used for production of radiation shields, photocatalytic and scintillation materials. Superfine nanocrystalline lead tungstate (PbWO4) is prepared by a chemical reaction between a solution of lead acetate and sodium tungstate with 5-20 % solution of lead acetate Pb(CH3COO)2·3H2O, prepared by dissolving lead acetate in a mixture of water and ethanol or acetone at a ratio of 1.5-1:1, dispersed as fine droplets, added to 2.5-10 % aqueous solution of sodium tungstate Na2WO4·2H2O on its surface with its continuous stirring. Disclosed method has a higher rate of yield and smaller dimensions of required equipment, due to lower consumption of solvents in preparation of solutions (5-10 times). Method also eliminates need for additional substances - dispersants, having limited application in industry.EFFECT: technical result of invention is to obtain nanocrystalline PbWO4, having average particle size of about 50 nm.1 cl, 2 dwg

Production of single-crystal diamond epitaxial large area films // 2577355
FIELD: process engineering.SUBSTANCE: this process comprises attachment of single-crystal diamond plates with surface orientation (100) to substrate and application of epitaxial diamond ply on said plates. Note here that, first edges of every said plate are finished before said attachment to make truncated tetrahedral pyramid with top plane oriented in crystallographic plane (100) and with four side faces oriented in planes of the type {311}. Every truncated pyramid is connected with substrate so that truncated pyramids contact with each other by their side faces. Then, diamond epitaxial ply is applied on truncated pyramids. Substrate whereto attached are monocrystalline diamond plates is made of silicon carbide. Said monocrystalline diamond plates are connected with substrate with the help of solder based on titanium and copper metals.EFFECT: increased area of monocrystalline diamond epitaxial film grown on diamond monocrystalline substrates.3 cl, 1 dwg

ethod producing single crystal fibers made of refractory materials // 2577260
FIELD: metallurgy.SUBSTANCE: method of producing single crystal fibers of refractory material comprises placing in a vacuum chamber the feeder starting material in the form of rods, feeding the laser radiation on the surface of the starting material and stretching the starting material to form a fiber, wherein when applying laser radiation at the surface of the parent material with a laser beam is scanned in two mutually perpendicular planes with frequencies f1=f2, equal to 200÷300 Hz, with amplitude A, equal 1.5-5 B, where B - the largest dimension of the feeder starting material.EFFECT: technical result of the invention is to reduce the energy loss of the laser light intensity is increased, the laser beam cross-section and the homogeneity of the resulting fiber structure.1 cl, 1 dwg
 
2550938.
Up!