Method of growing heat resistant monocrystals |
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IPC classes for russian patent Method of growing heat resistant monocrystals (RU 2404298):
Method of producing monocrystals of calcium and barium flourides / 2400573
Method involves crystallisation from molten mass through Stockbarger method and subsequently annealing the crystals through continuous movement of the crucible with molten mass from the upper crystallisation zone to the lower annealing zone while independently controlling temperature of both zones which are separated by a diaphragm. The crucible containing molten mass moves from the crystallisation zone to the annealing zone at 0.5-5 mm/h. Temperature difference between the zones is increased by changing temperature in the annealing zone proportional to the time in which the crucible moves from the beginning of crystallisation to its end, for which, while maintaining temperature in the upper crystallisation zone preferably at 1450-1550°C, in the lower annealing zone at the beginning of the crystallisation process temperature is kept at 1100-1300°C for 30-70 hours, thereby ensuring temperature difference of 450°C between the zones at the beginning. Temperature of the annealing zone is then lowered to 500-600°C in proportion to the speed of the crucible with the growing crystal. Temperature of the annealing zone is then raised again to 1100-1300°C at a rate of 20-50°C/h, kept for 18-30 hours after which the zone is cooled to 950-900°C at a rate of 2-4°C/h, and then at a rate of 5-8°C/h to 300°C. Cooling to room temperature is done inertially. Output of suitable monocrystals of calcium and barium fluorides with orientation on axes <111> and <001>, having high quality of transparency, uniformity, refraction index and double refraction is not less than 50%.
 Superstrong single crystals of cvd-diamond and their three-dimensional growth / 2389833
Method includes placement of crystalline diamond nucleus in heat-absorbing holder made of substance having high melt temperature and high heat conductivity, in order to minimise temperature gradients in direction from edge to edge of diamond growth surface, control of diamond growth surface temperature so that temperature of growing diamond crystals is in the range of approximately 1050-1200°C, growing of diamond single crystal with the help of chemical deposition induced by microwave plasma from gas phase onto surface of diamond growth in deposition chamber, in which atmosphere is characterised by ratio of nitrogen to methane of approximately 4% N2/CH4 and annealing of diamond single crystal so that annealed single crystal of diamond has strength of at least 30 MPa m1/2.
 Ceramic laser microstructured material with twinned nanostructure and method of making it / 2358045
Proposed laser material is a ceramic polycrystalline microstructure substance with particle size of 3-100 mcm, containing a twinned nanostructure inside the particles with size of 50-300 nm, made from halides of alkali, alkali-earth and rare-earth metals or their solid solutions, with vacancy or impurity laser-active centres with concentration of 1015-1021 cm-3. The method involves thermomechanical processing a monocrystal, made from halides of metals, and cooling. Thermomechanical processing is done until attaining 55-90% degree of deformation of the monocrystal at flow temperature of the chosen monocrystal, obtaining a ceramic polycrystalline microstructure substance, characterised by particle size of 3-100 mcm and containing a twinned nanostructure inside the particles with size of 50-300 nm.
Method for thermal processing of semi-finished abrasive tools on organic thermosetting binding agents / 2351696
Invention is related to the field of abrasive processing and may be used in production of abrasive tools for polishing of blanks from different metals and alloys. Full cycle of thermal processing of semi-finished abrasive tools on organic thermosetting binding agents includes stages of preliminary heating and hardening in microwave field of SHF- chamber with frequency of 2450 MHz for abrasive tool with thickness of up to 100 mm and with frequency of 890 - 915 MHz for abrasive tool with thickness of more than 100 mm. Prior to SHF-thermal processing semi-finished abrasive tools are placed into radio transparent steam-and-gas permeable container-thermostat. After temperature of thermosetting binding agent complete polymerization has been achieved, and after pause at this temperature, thermostat is withdrawn from SHF-chamber, and semi-finished abrasive tools are kept in thermostat until their temperature drops at least by 80°C. After that thermostat is opened, semi-finished products are cooled in open air and then withdrawn from thermostat.
Method for thermal treatment of half-finished abrasive tools on organic thermosetting binders / 2349688
Group of half-finished abrasive tools prior to thermal treatment is placed into thermally insulated steam and gas permeable radiolucent thermostat. Full cycle of mentioned half-finished articles thermal treatment is carried out. Cycle includes stages of preliminary heating and hardening of half-finished items group in microwave field of SHF-chamber with frequency of 2,450 MHz for abrasive tools with thickness of up to 100 mm and frequency of 890...915 MHz for abrasive tools with thickness of more than 100 mm to achieve temperature of organic thermosetting binder complete polymerisation with further maintenance at this temperature. In process of SHF thermal treatment volatile substances are forcedly and uniformly removed from free volume of thermostat through slots arranged in front and back walls of thermostat. Possibility for vapours of volatile substances to be saturated is eliminated with preservation of maximum possible effect of thermostat working area thermal insulation effect and provision of half-finished items temperature difference that does not exceed ±10% of its average level inside thermostat.
 Method of obtaining synthetic minerals / 2346887
Invention concerns obtaining synthetic minerals and can be applied in technics and jewellery. Method of artificial mineral synthesis is implemented by crucible method involving blend processing in plasma torch of plasmotron to obtain melt, melt drop feeding into crucible by plasma-forming gas flow with further crystallisation. Seeding agent is placed at crucible bottom in advance, and synthesis is performed at plasmotron output of 12 kW and blend feed rate of 2-3 g/min with simultaneous annealing of the melt crystallised on seeding agent in annular furnace for 2-3 hours at 1000°C. Preliminary placement of seeding agent to crucible bottom ensures accelerated crystal growth and higher process performance. Simultaneous annealing of artificial minerals reduces tension in end product significantly.
 Method of producing mono-crystalline plates of arsenide-indium / 2344211
Invention refers to semi-conductor technology of AIIIBV type compositions. The method is implemented by means of bombarding mono-crystalline plates of arsenide-indium with fast neutrons with following heating, annealing and cooling. The mono-crystalline plates are subject to bombardment with various degree of compensation at density of flow not more, than 1012 cm-2 c-1 till fluence F=(0.5÷5.0)·1015 cm-2 , while annealing is carried out at 850÷900°C during 20 minutes at the rate of heating and cooling 10 deg/min and 5 deg/min correspondingly.
Method of hardening dislocation-free silicon plates / 2344210
Invention refers to process of production of dislocation free plates of semi-conducting silicon cut out of mono-crystals, grown by Czochralski method, and applied for producing integrated circuits and discrete electronic devices. Method of upgrading mechanical hardness of mono-crystalline dislocation-free silicon plates with oxygen contents at the level 6×1017-9×1017 cm-3 is performed by two-stages thermal treatment in inert medium, for instance, in argon, initially at the temperature of 1000÷1020°C during 10-15 minutes, and further at the temperature of 600-650°C during 7.5-8.5 hours with following cooling in the air.
 Method of producing mono-crystals of indium antimonide alloyed with tin / 2344209
Invention refers to process of production of AIIIBV semi-conducting compositions. Mono-crystals of indium antimonide alloyed with tin are produced by means of bombardment with a full specter of reactor neutrons with successive heating, annealing and cooling. Heating is carried out at the rate of 20÷40 deg/min to temperature of annealing, defined by the formula Tanneal=450+(tgNsn-14)-7 [°C], where Nsn is concentration of introduced alloying addition of tin [cm-3]; annealing is performed during 20 minutes, while the successive cooling is carried out at the rate of 5-10 deg/min to the temperature of 350÷400°C, and further at the rate of 20-40 deg/min to an ambient temperature.
 Mehgod of growing cadmium telluride monocrystal / 2341594
Method of manufacturing cadmium telluride monocrystal lies in loading polycrystal half-product into crucible, hermetization with further crucible vacuuming, melting of half-product, cooling of obtained ingot, its standing at certain temperature and further cooling to room temperature; polycrystal half-product is loaded into crucible together with pure cadmium sample, whose weight is determined by Clapeyron-Mendeleev equation, crucible is exhausted to pressure 10-6-10-7 mm of mercury, half-product is melted, ensuring temperature gradient on height 1-5°C/cm, half-product melt is stood at melting temperature during 2-4 hours, then half-product is cooled at rate 0.5-1,0°C/hour to full crystallization; obtained crystal is cooled at rate 40-60°C/hour to temperature 920-960°C, crystal is stood at said temperature during 8-12 hours, then it is cooled again at rate 40-60°C/hour to temperature 820-860°C and stood at during 8-12 hours, then crystal is cooled to temperature 700-720°C and stood during 8-12 hours, after which crystal is cooled at rate 10-20°C/hour to room temperature and removed from crucible as end-product.
 Installation for growing monocrystals, for example sapphire / 2404297
Installation has a cylindrical chamber 1 with a cover 2 and a tray 3, a block of heat shields fitted in the chamber, a melting crucible with a seed holder on top, which is joined to a rod 9, a bearing swivel arm 11, a column 10 with rotary and displacement actuators 12 and 13 for the rod 9, a vacuum system 14, a feed system with a control cabinet 15 and a cooling system 16. The block of heat shields comprises upper and lower shields. The installation is fitted with a mechanism for raising the cover in form of an actuator 23 mounted on the swivel arm 11 and connected to the cover 2 of the chamber 1 by a flexible element 24 which is made in form of a chain, wherein the actuator 23 of the mechanism for raising the cover has a controlled torque-limiting clutch adjusted to a force which is sufficient for raising the cover 2, but slides when raising the rod 9 and the fixed cover. The installation is also fitted with a hoisting device 26 for raising the crucible and lower heat shields which is mounted on the column with possibility of turning about the axis of the column, wherein the hoisting device 26 is fitted with a withdrawing device for fitting and withdrawing the crucible. The upper heat shields are attached on the inner side of the cover 2 of the chamber 1, on the outside of which there are three inspection windows 21, 22, and the tray 3 of the chamber 1 has a water-cooled plug with a channel for feeding inert gas, and the control cabinet is fitted with a remote console 30 in form of an electronic knob mounted on the lateral surface of the cabinet.
Method of producing alumina nanoceramic / 2402506
Invention relates to production of optical materials which are transparent in the infrared (IR) spectrum with high transmission coefficient and high mechanical strength. The method involves preparation of a colloidal solution from finely dispersed γ-Al2O3 powder, from which a transparent supernatant - sol is extracted, which, through ultrasonic treatment, heating, acidification and thickening, is brought into a state gelling takes place after several days - formation of a viscous sol which is poured into a moulding hydrophobic container, where the said sol is kept until a moulded volume of gel is formed - gel workpiece. After removal from the mould, the gel workpiece undergoes thermal treatment in several steps, preferably three steps, where in each subsequent step temperature is approximately doubled, and the obtained polycrystalline mechanical strong material undergoes sintering at 1200-1750°C at pressure of 30-300 MPa for 20-30 minutes, after which temperature of furnace is brought down to ambient temperature under inert conditions.
 Sapphire monocrystal, method of making said monocrystal (versions) and melting device used therein / 2388852
Disclosed are monocrystalline sapphire sheets having desirable geometrical parametres, including length which is greater than the width, which is greater than thickness. The width is not less than 28 cm and thickness variation does not exceed 0.2 cm. The monocrystals can have other geometrical parametres such as maximum thickness variation, where after growth, the crystals can essentially have a symmetrical section of the neck linked to the transition from the neck to the main body of the crystal. The method of making the sapphire monocrystal involves formation of a molten mass in a crucible having a crystalliser. The horizontal cross-section of the crucible is not circular. It has a shape coefficient of 2:1. The shape coefficient is defined as the ratio of the length of the crucible to the width of the crucible, dynamic control of the temperature gradient along the crystalliser, and drawing the monocrystal from the crystalliser.
 Device for growing of volumetric rectangular monocrystals of sapphire / 2368710
Device contains vacuum chamber 1 with installed in it melting pot 2 with rectangular form-builder 3, located: in inner space of heater 4, collected from lamella, located by generatrix of heater 4, replicating shape of melting pot 2. Free ends of lamella are fixed on current leads 5. Melting pot 2 and generatrix of heater 4, by which there are located lamellas, allows squared shape, height of lamella exceeds height of melting pot for 20-25%, number of lamellas, located in middle part of each side of generatrix and compounding 1/3 of its width, 2-2.2 times less than number of lamella, located by edges of side, and cross-section area of form-builder for 35-45% less, than cross-section area of melting pot. Lamella can be implemented as solid or compound, consisting of two identical sections, located on over other. Squared shape of melting pot and generatrix of heater, by which there are located lamellas, it is implemented with fillet.
Method for growth of sapphire single crystals growth / 2355830
Invention is related to the field of sapphire single crystals growth and may be used in optical, chemical and electronic industry. Method includes vacuum melting of initial charge in chamber, single crystal pulling to seeding agent with its growth at simultaneous cooling of melt and further cooling of grown single crystal. Prior to beginning of single crystal growth additionally links are grown, at that height of links corresponds to height of observed melt meniscus and is equal to 0.5-4.0 mm, and time of their growth makes 1-20 minutes, at that crystallisation process is controlled by means of heater power reduction and provision of specified linear speed of crystallisation, and cooling of single crystal is done in vacuum for 30-35 hours with further delay for 10-12 hours in argon atmosphere at the pressure of 0.5 kgf/cm2 in chamber, opening of chamber cover and single crystal unloading.
Method for growing of sapphire single crystals from melt / 2350699
Invention is related to the field of single crystals growing from melts and may be used in enterprises of chemical and electronic industry for growing of sapphire single crystals of 1-6 quality category by Kyropulos method from melts on seed crystal. Method includes preparation of charge, its loading and melting by means of heating element in vacuum, seeding and pulling of single crystal, at that growing of single crystal is carried out to seed of technical quality of 6 category, which contains gas inclusions with size of up to 500 mcm and their accumulation, by means of seed crystal lowering by 10 mm every 10-12 minutes until it touches melt with temperature of 2330 K, which has no nucleation centers on the surface, seed crystal submersion for 20-30 sec in melt at 10-15 mm, lowering of heating element power until melt supercooling, which is required for nucleation of crystallisation grains on seed crystal surface in process of constrictions growth, and formation of cone-shaped convex crystallisation front in direction of melt.
 Device for crystallisation of leucosapphire melt / 2341593
Device for crystallisation of leucosapphire melt contains vacuum chamber, in which thermally are placed: insulated chamber, vacuum pump, connected with vacuum chamber by means of branch pipe, thermal energy source, boat with charge, located on common with thermal energy source axis, vacuum depth sensor, connected with vacuum chamber by means of branch pipe, melt temperature sensor, electric power supply unit, connected with input with electricity network and control unit, which by means of first input is connected with vacuum pump input, and by means of second input - with thermal energy source, introduced into system are: channel of optical connection passing through walls of thermally insulated and vacuum chambers to outer surface of vacuum chamber, and oriented with maximum of diagram of radiation direction at boat content, connected with its output with optical input of melt temperature sensor, electromechanical drive of boat movement, connected with its output with boat, electric magnet, located on the same axis as thermal energy source in thermally insulated chamber and connected galvanically with third output of control unit, first master - master of boat content temperature, first element of comparison, connected by discharge by first inputs with outputs of melt temperature sensor, by second inlets - with first master outputs, by first output - with first controlling input of control unit, time impulse generator, impulse distributor, connected by signal input with impulse generator output, by controlling input - with second output of first element of comparison, and by output - phase-by phase with inputs of electromechanical drive of boat movement, analog-digital converter, connected by its input with output of vacuum depth sensor, second master - master of vacuum depth in vacuum chamber, second element of comparison, connected discharge-by-discharge by first inputs with outputs of second master, and with second inputs - with outputs of vacuum depth sensor in vacuum chamber, and OR element, connected by first input with output of second element of comparison, by second input - with first output of first element of comparison, and by output - with second controlling input of control unit, control unit being connected by power inputs with outputs of power supply unit, by first output - with input of vacuum pump, with second output - with input of thermal energy source, sensor of vacuum depth in vacuum chamber is made on inverse-magnetron vacuum-meter, sensor of melt temperature - on multi-channel and radiation pyrometer, and electromechanical drive of boat movement - on step engine.
 Refractory oxide monocrystals growing method / 2320789
Method for growing refractory oxide mono-crystals by directional horizontal crystallization comprises steps of creating in vacuum chamber by means of heating devices temperature field; melting in created field initial crystallized material placed in container being open upwards reservoir in the form narrowed at one side parallelepiped shaped boat; forming crystal from oriented mono-crystalline seed arranged in narrowed part of container and made of material corresponding to grown crystal due to moving container with melt charge in gradient temperature field. At growing process, crystallization speed is controlled in axial, radial and vertical directions by regulating relations of heat flux values of heating devices irradiation, namely heat flux of radiant energy incident to melt heel surface and conductive heat flux passing through lateral walls and bottom of container. Desired temperature gradients of temperature field along interface of melt material phases and grown crystal - crystallization front are provided due to setting difference between temperature of phase interface and equilibrium melting temperature equal to 15 - 25°C. Inclination angle of crystallization front relative to plane of container bottom at forming vertical temperature gradient is set in range 55 -90°. Width of seed is selected in range 3 - 5 mm; enlargement angle of mono-crystal is set in range 100 - 140°; values of enlargement arms of mono-crystal are selected up to 300 mm. Invention provides increased useful surface area (rectangular portion) of grown crystals by 30 - 45% and flat crystallization front in zones of lateral corrugations of container.
 Device for growing shaped sapphire monocrystal / 2316621
Device comprises vacuum chamber with melting pot and molding unit, wolfram heater, shields, rod with the holder for seed provided with a mechanism for lifting crystal and mounted outside of the chamber, and melt make-up system made of a hopper with tube and system for control of heating and rate of crystal lift. The device is additionally provided with roasting vacuum chamber that is mounted above the chamber with melting pot and molding unit coaxially to it and the system for synchronization of mass of the crystal to be grown and the flow rate of the make-up material. The roasting chamber has autonomous heater whose height is equal or exceed the maximum size of the length of the crystal to be grown. The diameter of the roasting chamber is 0.6-0.9 of the diameter of the bottom chamber. The baffle provided with openings for the rod with seed holder is interposed between the chambers.
 Device for growing of the rectangular monocrystals of sapphire / 2310020
The invention is pertaining to the technology of growing from melts of the monocrystals of sapphire and may be used at production of the volumetric crystals with the crystallographic orientation along the axis <1010> or <1120>. The device contains the vacuum chamber with the installed in it the crucible, the rectangular shaper, the heater assembled out of the lamellas fixed on the current leads, the screens, the rod with the seed-crystal holder and the systems adjusting the hoisting speed of the seed crystal and power of the heater. The crucible, the generatrix of the lamellas and the deflector have the rectangular form, between the bottom of the crucible and the shaper there is the spacing, the altitude of the walls of the shaper exceeds the altitude of the crucible. The wall of the shaper in their upper part are made slit along the ribs and bent off along the slits in the direction of the walls of the chamber, the shaper rests on the upper edge of walls of the crucible by its slit parts. The technical result of the invention consists in the rise of the output of the single crystals up to 60 % due to reaching of integrity of the geometrical shape of the crystal with the crystallographic orientation along the axis <1010> or <1120> and acceleration of the growing process.
Installation for growing monocrystals, for example sapphire / 2404297
Installation has a cylindrical chamber 1 with a cover 2 and a tray 3, a block of heat shields fitted in the chamber, a melting crucible with a seed holder on top, which is joined to a rod 9, a bearing swivel arm 11, a column 10 with rotary and displacement actuators 12 and 13 for the rod 9, a vacuum system 14, a feed system with a control cabinet 15 and a cooling system 16. The block of heat shields comprises upper and lower shields. The installation is fitted with a mechanism for raising the cover in form of an actuator 23 mounted on the swivel arm 11 and connected to the cover 2 of the chamber 1 by a flexible element 24 which is made in form of a chain, wherein the actuator 23 of the mechanism for raising the cover has a controlled torque-limiting clutch adjusted to a force which is sufficient for raising the cover 2, but slides when raising the rod 9 and the fixed cover. The installation is also fitted with a hoisting device 26 for raising the crucible and lower heat shields which is mounted on the column with possibility of turning about the axis of the column, wherein the hoisting device 26 is fitted with a withdrawing device for fitting and withdrawing the crucible. The upper heat shields are attached on the inner side of the cover 2 of the chamber 1, on the outside of which there are three inspection windows 21, 22, and the tray 3 of the chamber 1 has a water-cooled plug with a channel for feeding inert gas, and the control cabinet is fitted with a remote console 30 in form of an electronic knob mounted on the lateral surface of the cabinet.
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FIELD: chemistry. SUBSTANCE: crystals are grown using the Kyropoulos method with an optimum annealing mode, carried out while lowering temperature of the grown monocrystal to 1200°C at a rate of 10-15°C/hour and then cooling to room temperature at a rate of 60°C/hour. EFFECT: obtaining large monocrystals with less stress in the entire volume, and which are suitable for mechanical processing in order to obtain crystal wafers with zero orientation. 1 ex, 1 dwg
The invention relates to the cultivation of refractory single crystals from the melt using the seed crystal, in particular crystals of sapphire, ruby. When growing large single crystals of sapphire or ruby from a large volume of melt is most often used methods of kyropoulos method, the Czochralski method, related to the crucible methods of growing from the melt. Using the kyropoulos method grown sapphires with a diameter of more than 350 mm and weighing more than 80 kg, the Ratio of diameter to height of the single crystal may vary in the range of 3:1-1:3 (Ref. Dobrovinsky ER, Litvinov L.A., reed CENTURIES encyclopedia of sapphire. Kharkov, Institute of single crystals, 2004, s). Monocrystalline sapphire is most commonly used for the manufacture of substrates with orientation (0001). The most rational cutting of bulk crystals on the thin plate will be the case when the optical axis (0001) parallel to the axis of the crystal has a cylindrical shape with a diameter close to the desired diameter billet products. This so-called crystals zero orientation (See. Rubashov M.A., Burdov GI, V. Gavrilov. and other heat-Resistant insulators and their junctions with metal in the new technology. M, Atomizdat, 1980, p.123). However, obtaining such bulk crystals using the kyropoulos method is a technology problem. When growing crystals zero orientation p of the technological regimes, used for crystals 90°orientation, when plates cut perpendicular to the axis of the crystal, the crystals zero orientation are block and siliconephenyl, which limits their further application. Consider the problem of producing bulk single crystals of sapphire using the kyropoulos method in crystallochemical aspects. The lattice Al2O3formed ions Al3+and-2. If the anions Of-2to depict in the form of balls, the crystal lattice can be represented in the form of their hexagonal close packing. The cations Al3+located in the octahedral voids between close-Packed anions On-2filling 2/3 of voids. Octahedral void is surrounded by six spheres, if the radius of each of them to take over the unit, the void is the ball of radius 0,41. The ratio of the ionic radii Of-2and Al3+(of 1.40 Å and 0.57 Å) allows cations to be placed in the voids of the packing of anions, distorting the lattice, while not going beyond the limits of stability of the octahedral positions. The crystalline lattice of sapphire is very elongated along the optical axis "C". The ratio C/a, where "C" and "a" parameters of a single cell of sapphire at room temperature is 2.7. With increasing temperature the lattice parameters of sapphire rise (see the above source EN is yclopedia sapphire", p.19). When the crystal growth occurs in the direction of the axis (0001), the vertical temperature gradient of thermal field is most strongly affects the crystalline structure. If we consider the stresses in the crystals as a condition of the crystal structure, in which its parameters are different from the equilibrium for a given temperature (see the above source, heat-Resistant insulators and their junctions with metal in the new technique, p.124), to reduce the need to increase the time annealing at high temperature. In the above source "encyclopedia of sapphire on SS, 409 expressed approval that the sapphire volumetric strain relaxes at sufficiently high temperatures (about 2000 K). Moreover, the relaxation occurs in the first hours of annealing. Also during high-temperature annealing to reduce internal stresses in sapphire changes the density of single dislocations, the length of the block boundaries and corners of their misorientation. The speed of the processes of annihilation, polygonization and "scattering" of dislocation boundaries greatly depends on the temperature, and the closer the TOTG.to Tpl.the higher velocity. In the same source literature on s indicated that previous experimental experience shows the ambiguity of the influence of thermal treatment on structural owls shall chenstvo and mechanical properties of sapphire. For the prototype of the present invention to adopt a Method of growing refractory single crystals", protected by the RF patent №2056463, publ. 20.03.1996 index IPC SW 15/00, SW 29/20. This solution relates to the technology of single crystal type sapphire, ruby, garnet using the kyropoulos method (in the prototype mistakenly - Czochralski) and includes a vacuum melting of the original charge, the introduction of the seed, the pulling of the single crystal and simultaneously cooling the melt at a rate of 0.5 to 2.0°C/h, and the cooling of the single crystal carried out with a speed of 25-50°C/h In the above method focuses on the operation mode of annealing, which is reported as optimum for obtaining a single crystal without the stress. It is also argued that slower speeds do not lead to a noticeable improvement of the crystal, and only lengthen the process. However, in the prototype are not described process conditions to obtain crystals of the zero orientation. These crystals require a softer mode of annealing. The present invention is to obtain bulk single crystals, less stressful and suitable for mechanical processing in order to obtain plates of crystals zero orientation. The technical result is achieved empirically, which is installed, h is about reducing the speed of decreasing the annealing temperature several times at the initial stage, i.e. at the highest temperatures, in comparison with the known method allows to grow besplatnye crystals zero orientation. The problem is solved in the method of growing refractory single crystals, including vacuum melting of the original charge, the introduction of the seed crystallization of the melt prior to the formation of a single crystal of the maximum possible size of this volume of the melt and subsequent annealing of the grown single crystal, in which unlike the prototype, the annealing is performed at a lower temperature up to 1200°C with a rate of 10-15°C./hour, and the subsequent cooling of the single crystal occurs at a rate of 60°C/hour. The drawing schematically shows the grown crystal in the form of boules with the image of the crystallographic lattice of one cell of the crystal, where 1 is the outer contour of the crystal boules, 2 - hexagonal cell of the crystal structure, 3 - geometric axis of the crystal, which coincides with the optical crystallographic axis with crystallographic index (0001) crystals zero orientation, 4 - axis "a", which is the axis perpendicular to the axis "C"having a crystallographic index A specific example of implementation of the method. Growing a single crystal of sapphire is carried out in electric furnaces of the type SVN-150 or omega. As charge use fight crystals, verase is related to the method of Verneuil, or pre-sintered powder. Oven vacuum up to 10-5mm Hg and turn up the heat to melting of the charge that is controlled visually. A seed crystal is lowered to the surface of the melt having a temperature of crystallization (for sapphire - 2030°C). At the initial stage of the process lifting the seed lead with a speed of 0.3-0.5 mm/hour for 20 hours, and then increase the speed to 0.5-1.0 mm/h. Simultaneously with the rise of a growing crystal include reducing the temperature at a rate of 0.5 to 2.0°C per hour. The process of crystal growth ends when the entire melt secretariats to whet your appetite. Off the rise of the grown crystal and set automatic reduction of its temperature during annealing which is carried out as follows: the decrease in temperature up to 1200°C carried out with a rate of 10-15°C./hour and subsequent cooling to room temperature is carried out at 60°C/hour. The obtained single crystal height of 160 mm and a thickness of about 80 mm in average diameter, height, weight 4.5 kg, were investigated for the presence of blocking by using a polarimeter. Studies have shown the absence of blocking. The result of cutting the crystal along the axis of the zero orientation of the obtained plates of sapphire with a diameter of 65 mm for the manufacture of besplatnih substrates, lenses or screens, used in electronic, optical and chemical the industry. The method of growing refractory single crystals, including vacuum melting of the original charge, the introduction of the seed crystallization of the melt prior to the formation of a single crystal of the maximum possible size of this volume of the melt and subsequent annealing of the grown single crystal, characterized in that the annealing is performed at a lower temperature up to 1200°C with a rate of 10-15°C./h, and the subsequent cooling of the single crystal is conducted at 60°C/H.
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