4257 results about "Seed crystal" patented technology

The invention discloses a preparation method of an ultrahigh-heat-conductivity silicon nitride ceramic chip, and relates to the technical field of silicon nitride ceramic chips. Comprising the following steps: step 1, carrying out ball milling and defoaming on raw materials to prepare slurry, and carrying out tape casting to obtain a green body; step 2, laminating the green bodies with the boron nitride powder therebetween for glue discharging to obtain laminated green bodies; and step 3, sintering the laminated green body in a protective atmosphere to obtain the ultrahigh-heat-conduction silicon nitride ceramic chip. The preparation method has the beneficial effects that the addition amount of magnesium oxide is controlled, and the seed crystal is added, so that the growth of crystal grains is controlled while the addition of additional oxygen content is reduced, and the heat conductivity and bending strength of the obtained silicon nitride ceramic chip are improved. And meanwhile, the binder is partially introduced into the modified polysilazane, so that the quality of the silicon nitride ceramic chip is improved, the generation of impure phases in the high-temperature sintering process is avoided, and the practical application is met.

The invention belongs to the technical field of metal powder preparation, and discloses a method for preparing silver powder through reduction of hydrazine hydrate with the adjustable particle size. The preparation method comprises the following steps that a first dispersing agent is dissolved in deionized water, a silver-ammonia solution and a hydrazine hydrate solution are sequentially added, stirring reaction is conducted, and nano-silver seed crystal sol is obtained; uniformly mixing the obtained nano-silver seed crystal sol with a hydrazine hydrate solution and a second dispersing agent to obtain a reducing base solution; adding a surface modifier into absolute ethyl alcohol, and uniformly dissolving to obtain a surface modification coating solution; preparing a silver-ammonia solution, adding the prepared silver-ammonia solution into the reducing base solution, then adding the surface modification coating solution, and stirring for reaction to obtain silver powder slurry liquid; and after solid-liquid separation, a solid phase is taken, washed and dried, and silver powder is obtained. The preparation method is simple in process, the particle size of the silver powder can be adjusted through the adding amount of the seed crystal, and the prepared silver powder particles are uniform in particle size distribution, high in dispersity and suitable for the fields of conductive silver paste, electronic packaging and the like.

The invention belongs to the technical field of crystal growth, and provides a low-resistivity silicon carbide single crystal growth method and system and a single crystal, silicon carbide powder is uniformly paved at the bottom of a graphite crucible, metal carbide material particles are uniformly paved on the surface of the silicon carbide powder, and silicon carbide seed crystals are adhered to the top of the graphite crucible; the graphite crucible is sealed, and the interior of the graphite crucible is vacuumized; heating the graphite crucible subjected to vacuumizing treatment, filling carrier gas into the graphite crucible, then slowly replacing the carrier gas with doped source gas, slowly increasing the growth pressure to a set pressure, and growing a buffer layer; after the growth of the buffer layer is completed, changing the growth condition to grow the heavily doped silicon carbide single crystal; and after the growth of the crystal is completed, cooling the graphite crucible subjected to vacuumizing treatment, so that the crystal is naturally cooled, and the low-resistivity silicon carbide single crystal is obtained. The doping concentration of the silicon carbide single crystal can be improved, and the resistivity of the silicon carbide material can be reduced.

The invention provides a lithium iron phosphate material and a preparation method thereof, a positive pole piece and a secondary battery, and relates to the field of positive pole materials. The lithium iron phosphate material meets the condition that sigma b / sigma f is larger than or equal to 1.10 and smaller than or equal to 5.00, sigma b is the sample standard deviation of the circularity C of large-particle lithium iron phosphate, sigma f is the sample standard deviation of the circularity C of small-particle lithium iron phosphate, and the large-particle lithium iron phosphate and the small-particle lithium iron phosphate with different morphologies are matched with each other through the difference of the sample standard deviation of the circularity of the large-particle lithium iron phosphate and the sample standard deviation of the circularity of the small-particle lithium iron phosphate. Therefore, the lithium iron phosphate material has good tap density and specific surface area. According to the preparation method of the lithium iron phosphate material, the large-particle-size iron phosphate seed crystal partially coated with polydopamine is subjected to vacuum dehydration to obtain the modified iron phosphate seed crystal with the dehydrated surface layer, the morphology of the large-particle iron phosphate prepared by precipitation reaction is influenced, and the iron phosphate material is obtained by utilizing the large and small seed crystals through a coprecipitation method. And finally, the lithium iron phosphate material with good tap density and specific surface area is prepared.

Crystal growth systems with a baffle are provided. In one example, a crystal growth system for growing crystalline material, the crystalline material including silicon carbide, includes a seed holder configured to hold a silicon carbide seed crystal. The seed crystal provides a growth surface for growth of the silicon carbide crystalline material. The system includes a crucible at least partially defining a crystal growth chamber. The system includes a source material. The system includes one or more baffles within the crystal growth chamber and spaced apart from the source material. The one or more baffles include one or more apertures defined through the one or more baffles. The baffle includes a long dimension that is non-perpendicular to the growth surface of the seed crystal.

Disclosed in the present invention is a process for deeply removing fluorine from wastewater by means of an induced crystallization method in sludge backflow. The process comprises the following steps: step 1. placing lime powder and deionized water in a seed crystal reactor to prepare lime milk and at the same time putting a calcite seed crystal into the seed crystal reactor; step 2. introducing high-concentration fluorine-containing acidic wastewater into a reactor; and step 3. introducing the lime milk obtained in step 1 into the reactor in step 2 to undergo a reaction, wherein during the reaction, the pH value of the mixed solution is controlled to remain neutral. The present invention is based on a high-density sludge method (HDS process). By utilizing the HDS process, the advantages of effectively improving the sludge density, reducing the lime consumption, facilitating the operation, and enabling the water quality of an effluent to be more stable are realized. In conjunction with induced crystallization technology, an induced crystallization process in a high-density sludge backflow is formed to promote precipitation and crystallization and allow sedimentation to proceed quickly, thereby shortening the process time and overcoming the defects of traditional lime precipitation methods.

The invention relates to the technical field of concrete preparation, in particular to high-performance self-compacting concrete and a preparation method thereof, solves the defects in the prior art, and comprises the following components: cement, fly ash, slag powder, graphene oxide, nano-silica aerogel, a water reducer and an air entraining agent. Through silanization modification and magnetic field induction, the problem of interface incompatibility of GO and SA is solved. Graded mass transfer paths are formed between nano layers of GO and mesopores and macropores of SA. And the CaCO3 seed crystal in the SA hole directionally guides the oriented growth of the C-S-H gel, so that the early strength development rate is increased.

The invention discloses a stepped treatment process for multi-path recycling of oil and gas field drilling mud, which comprises the following steps: oxidizing and breaking gel of the drilling mud to scatter the mud structure, and then granulating and coagulating; then, carrying out the following gradient treatment: step 1, filtering the outlet water of granulation and coagulation, and taking the filtrate as reinjection water; step 2, carrying out nucleation granulation reaction on the filtrate obtained in the step 1, using effluent for preparing drilling fluid, and carrying out solid waste treatment on solid-phase crystal seeds and solid-phase mud cakes subjected to granulation and coagulation; and step 3, carrying out ozone flotation reaction on the effluent obtained in the step 2, wherein the effluent is used for preparing the guanidine gum fracturing fluid. According to the method, resource recycling of the waste drilling mud is achieved, the usage amount of a gel breaker in a traditional gel breaking and filter pressing technology is reduced, a filter pressing plate is omitted, the treatment efficiency in the mud recycling treatment process is improved, the treatment cost of the waste water-based drilling mud is reduced, different recycling ways can be met, and the method is suitable for popularization and application. And specific operation is flexible and changeable.

The invention provides a method for precipitating nickel and cobalt in a solution containing nickel and cobalt and a cobalt nickel hydroxide product. The method comprises the following steps: step S100, carrying out a seed crystal pretreatment reaction on a nickel-cobalt-containing solution by adopting first nickel-cobalt precipitation underflow to form pretreated nickel-cobalt ore pulp; step S200, adding an alkaline precipitation inducer into the second nickel-cobalt precipitation underflow or the first nickel-cobalt precipitation overflow to carry out alkali conversion reaction to form alkali conversion crystal mush; s300, the pretreated nickel-cobalt ore pulp and alkali conversion crystal mush are continuously introduced into a reactor for a nickel-cobalt precipitation reaction, and nickel-cobalt precipitated ore pulp is obtained; step S400, continuously performing dense separation treatment on the ore pulp subjected to nickel-cobalt precipitation; s500, the third nickel-cobalt precipitation underflow is filtered and washed in sequence, a nickel-cobalt hydroxide product is obtained, and the problems that in the prior art, when nickel and cobalt are precipitated through a nickel-cobalt-containing solution, MHP is small in particle size and not prone to sedimentation, the water content of a filter cake is high, or the precipitation rate is poor, and the magnesium content is high before technical improvement are solved.

The invention belongs to the technical field of semiconductor photoelectric devices, and particularly discloses a preparation method for realizing growth of ultralow-defect perovskite single crystals based on steric hindrance control, which comprises the following steps: preparing a perovskite single crystal precursor solution: dissolving a perovskite single crystal precursor in a homogeneous solvent with coordination capability to prepare the precursor solution; and generating a perovskite single crystal seed crystal: heating the prepared perovskite single crystal precursor solution until microcrystals appear, selecting to form good crystals, drying, and storing as the seed crystal for future use. And growing the perovskite single crystal: putting the generated perovskite single crystal seed crystal into the perovskite single crystal precursor solution, heating, and growing to obtain the perovskite single crystal. The preparation method comprises the following steps: dissolving a precursor in a homogeneous solvent with coordination capability through a temperature reversal crystallization method, and adjusting the temperature to carry out single crystal growth; according to the steric hindrance theory, the growth temperature is selected by regulating and controlling the solvent proportion, and the perovskite single crystal with ultralow defect density is obtained.

The invention provides a method for manufacturing a super-flat polycrystalline diamond film on a large scale. The method comprises the following steps: (1) growing a layer of polycrystalline diamond film on a growth substrate with a diamond seed crystal on the surface by adopting a chemical vapor deposition method; (2) cutting off at least one part of the substrate after growth to form a boundary for jointing the polycrystalline diamond film and the growth substrate; (3) sticking a stripping adhesive tape; and (4) the stripping adhesive tape is pulled to strip the polycrystalline diamond film from the surface of the growth substrate, so that the nucleation surface of the polycrystalline diamond film is exposed, and the roughness of the exposed nucleation surface is smaller than that of the growth surface. According to the method, the nucleation surface of the grown polycrystalline diamond film is turned over, the novel and simple method is developed to manufacture the polycrystalline diamond film which is reasonable in price, capable of growing on a large scale, super-flat and transferable, and the method has huge potential in practical application.

A method for preparing flaky silver powder with the controllable single-crystal structure size comprises the steps that firstly, a silver nitrate aqueous solution is prepared, then a dispersing agent polyvinylpyrrolidone aqueous solution is added and stirred to be uniform, and then a trisodium citrate aqueous solution is added for reacting to prepare nano-silver seed crystals; finally, adding a polyvinyl alcohol aqueous solution serving as an end-capping reagent into the solution, and coating PVA on the crystal face of the nano-silver seed crystal {100} through a grinding dispersion machine to form a nano-silver seed crystal mixed solution containing silver nitrate, polyvinylpyrrolidone and coated PVA; preparing a nitric acid aqueous solution and an ascorbic acid aqueous solution, mixing and adding the nitric acid aqueous solution and the ascorbic acid aqueous solution into a reaction kettle, adding the mixed solution containing silver nitrate, polyvinylpyrrolidone and the PVA-coated nano-silver seed crystal under a stirring condition, and mixing to generate a reduction reaction; the PH value is adjusted through nitric acid to control the reduction reaction speed, the growth direction of nano-silver seed crystals is controlled through PVA, the particle size growth size is controlled through polyvinylpyrrolidone, and finally the flaky silver powder with the controllable single-crystal structure size is obtained.

The embodiment of the invention provides a Czochralski method crystal growth device and a regulation and control method, and relates to the technical field of crystal growth. The Czochralski method crystal growth device comprises a furnace body, a crucible, a first magnetic field device, a seed rod and a second magnetic field device, the crucible is arranged in the furnace body, and the first magnetic field device is arranged on the outer side of the crucible in a surrounding mode and located in the furnace body. The seed rod is arranged in the furnace body and is spaced from the crucible; the second magnetic field device is arranged on the seed crystal rod and is positioned in the furnace body; wherein the first magnetic field device is used for generating a magnetic field and acting on a melt in the crucible; the second magnetic field device is used for generating a magnetic field and acting on a growth interface of the melt. The Czochralski method crystal growth device can effectively inhibit convection of melt, so that solute distribution is uniform, and crystal defects are reduced; and the crystal structure can be optimized, and accurate regulation and control of solute are realized, so that the quality and the performance of the crystal are integrally improved.

The invention relates to the technical field of lithium ion battery materials, and provides a lithium iron phosphate positive electrode material, a preparation method thereof and a lithium battery. The preparation method of the lithium iron phosphate positive electrode material comprises the following steps: performing a first coprecipitation reaction on a first iron source solution and a first phosphorus source solution in the presence of a polymer monomer to obtain an iron phosphate seed crystal; performing a second coprecipitation reaction on the second iron source solution and the second phosphorus source solution in the presence of a polymer monomer and an iron phosphate seed crystal to obtain iron phosphate dihydrate; iron phosphate dihydrate, a lithium source and a carbon source are mixed and then subjected to spray drying, the mixture is placed in a rotary kiln to be sintered, carbon-coated lithium iron phosphate with the large particle size and carbon-coated lithium iron phosphate with the small particle size are prepared at different sintering temperatures respectively, and the carbon-coated lithium iron phosphate with the different particle sizes are mixed according to the mass ratio to obtain the lithium iron phosphate positive electrode material. The lithium iron phosphate positive electrode material has relatively good spherical morphology, so that the lithium iron phosphate positive electrode material has relatively high compaction density and electrical properties after grading.

The utility model discloses a substrate table for preparing monocrystal diamond by microwave plasma, which relates to the technical field of monocrystal diamond preparation and comprises a first molybdenum plate and a first molybdenum ring, the first molybdenum plate is used for bearing seed crystal, and a first groove is arranged on the bottom surface of the first molybdenum ring. The inner side wall of the first groove can be tightly attached to the outer side wall of the first molybdenum sheet, and a first through hole is formed in the inner top surface of the first groove; according to the substrate table for preparing the monocrystal diamond through the microwave plasma, the utilization rate of plasma energy can be increased.

The preparation method comprises the following steps: obtaining a ZnO nano-particle seed crystal layer by a dip-coating-calcining method, and growing the ZnO nano-particle seed crystal layer on a porous ceramic membrane; inducing growth of ZnO nano-clusters on the surface of the ceramic membrane on which the ZnO nano-particles grow and in pore channels of the ceramic membrane through a hydrothermal reaction; and finally, soaking the ceramic membrane on which the ZnO nano-cluster grows in an n-octyltriethoxysilane-absolute ethyl alcohol solution, and carrying out silane chemical grafting treatment. A firm micro-nano composite multilevel structure is obtained on the surface and in pore channels of the ceramic membrane after modification through the method, meanwhile, the surface free energy of the surface and pore channels of the ceramic membrane is reduced through n-octyltriethoxysilane, the surface and the pore channels of the ceramic membrane have super-hydrophobic performance, and the preparation method is simple in preparation process, short in period and suitable for industrial production. And the universality is high.

The invention relates to the technical field of silicon carbide single crystal preparation, in particular to a method and a device for growing silicon carbide single crystals by a liquid phase method. The embodiment of the invention provides a method for growing a silicon carbide single crystal by a liquid phase method, which comprises the following steps of: heating and melting a material containing a solvent element in a crucible resistant to high-temperature melt corrosion to obtain a high-temperature solution in the crucible; putting a raw material block prepared from silicon carbide into the high-temperature solution so as to provide a carbon element and a silicon element in the high-temperature solution; and driving a silicon carbide seed crystal to enter the crucible by using a first rotary lifting rod, so that the silicon carbide seed crystal is in contact with the liquid level of the high-temperature solution to grow the silicon carbide single crystal. The embodiment of the invention provides a method and a device for growing silicon carbide single crystals by a liquid phase method, which can realize long-time stable growth of silicon carbide crystals.

The invention relates to the field of silicon carbide crystal growth, in particular to a high-efficiency silicon carbide single crystal growth method which comprises the following steps: (S.1) providing a reverse thermal field environment of which the temperature is sequentially reduced from top to bottom in the vertical direction; (S.2) heating the silicon carbide powder so as to generate silicon carbide sublimation gas; (S.3) the silicon carbide sublimation gas is introduced into the thermal field environment along with the carrier gas, so that the silicon carbide sublimation gas is layered under screening of the carrier gas, and a silicon-rich atmosphere located at the top of the thermal field environment and a supersaturated atmosphere located at the bottom of the thermal field environment are obtained; and (S.4) contacting the supersaturated atmosphere with a seed crystal arranged at the bottom of the thermal field environment so as to grow the silicon carbide single crystal on the surface of the seed crystal. Through the reverse thermal field design, carrier gas screening layering and carbon powder dynamic compensation mechanism, the problems that in traditional silicon carbide single crystal growth, silicon gas phase enrichment inhibits the crystallization rate, and defects are caused by unbalance of the stoichiometric ratio are systematically solved.

The invention relates to a czochralski method-based crystal growth interface shape detection method and device. The method comprises the steps that: a seed crystal temperature T and an interface electromotive force U at the same time in a crystal growth process are collected, and a T-U curve of the interface electromotive force U changing with the seed crystal temperature T is obtained; the change trend of the shape of a crystal growth interface in real time is judged by observing the deviation between the T-U curve and a reference line, wherein the reference line is a straight line passing through the starting point of the T-U curve, and the slope of the straight line is the Seebeck coefficient of the crystal. The invention also relates to a device used by the method. The detection method provided by the invention can detect the change trend of the shape of the crystal growth interface in real time in the crystal growth process, and can be applied to Czochralski method growth equipment for various single crystals such as lithium niobate, lithium tantalate, sapphire, yttrium aluminum garnet and the like.

The invention discloses a preparation device and method for growing a large-size silicon carbide single crystal. A raw material gas phase in a high-temperature area is transmitted to the surface of a seed crystal in a low-temperature area for crystal growth by using a physical gas phase transmission method; the device comprises a furnace chamber, a movable sectional type heating system, a thermal insulation material, a graphite crucible, porous graphite, a seed crystal unit, a crystal growth induction forming device and an electric field device. The method comprises the following steps: installing a seed crystal unit in a crucible filled with silicon carbide powder, placing the crucible in a heater, and carrying out a crystal growth stage to prepare the silicon carbide single crystal. The whole growth process of the crystal is in a constant temperature state, thermal stress caused by the temperature difference between the growth end and the seed crystal end and the temperature difference between the crystal edge and the crystal center in the top end seed crystal method crystal growth process is avoided, the dislocation defect of the crystal is reduced, and finally the high-quality silicon carbide single crystal is obtained. And the production cost is reduced.

To provide a high resistivity polycrystalline substrate, and a method for manufacturing the high resistivity polycrystalline substrate.SOLUTION: A method contains steps of: forming a polycrystalline substrate having a high resistibility (e.g., 1×10^5 or 1E+5 ohmic centimeter or more); forming a single crystal substrate by fusing a semiconductor grade silicon with a high grade, and thereafter, using a seed crystal, and starting a formation of the single crystal; bonding a second surface of the polycrystalline substrate when the polycrystalline substrate and the single crystal substrate are formed to a third surface of the single crystal substrate by using a surface active bonding (SAB) technique; and removing one part of the single crystal substrate.SELECTED DRAWING: Figure 4A

The invention provides a preparation method of a bionic microfluidic device for researching fluid migration in carbonate rock micro-nano fractures, which comprises the following steps: step 1, analyzing and classifying scanning electron microscope images of carbonate rock core slices through a random forest algorithm to generate a chip design drawing; step 2, based on the chip design drawing, re-etching a crack structure through a photoresist template and polydimethylsiloxane by adopting a soft lithography technology, and bonding with a glass substrate to form a micro-fluidic chip; and step 3, injecting a precursor liquid containing the calcite nano seed crystal into the micro-fluidic chip flow channel, fixing the seed crystal through ultraviolet irradiation, and injecting a saturated equilibrium liquid to realize calcium carbonate mineral precipitation so as to form the bionic micro-fluidic device. The method can be used for coupling research of all fluids and carbonate rock fractures, and a method for recovering the carbonate rock fracture structure to the maximum extent and a rock surface property cloning method are provided.

The invention relates to a single crystal diamond and a preparation method and application thereof. The preparation method comprises the following steps: performing etching treatment on a diamond seed crystal; then introducing a carbon source, hydrogen and chlorine, and carrying out deposition growth of the monocrystal diamond; after deposition growth is finished, post-treatment is conducted, and the single crystal diamond is obtained. Chlorine and hydrogen are introduced in the chemical vapor deposition process at the same time, selective growth of a diamond phase can be promoted, chlorine can help to reduce formation of non-diamond carbon (such as graphite), and therefore the quality and the growth speed of diamond single crystals are improved, and the dislocation density is reduced.

The invention discloses an ettringite / nano hydrated calcium silicate early strength agent as well as a preparation method and application thereof, and belongs to the technical field of concrete admixtures. The early strength agent comprises ettringite and nano calcium silicate hydrate, the ettringite is in a short rod shape and has three sizes, and the size distribution and the percentage of the ettringite accounting for the total mass of the ettringite are as follows: the diameter of the ettringite is 40-50nm, and the percentage of the ettringite is 40-80%; the diameter is 70-90 nm, and the proportion is 10-30%; the diameter is 120-150nm, and the proportion is 10%-30%. The ettringite with a proper size is compounded according to a specific proportion and then is combined with the nano hydrated calcium silicate to form the composite seed crystal, and the composite seed crystal is used as the early strength agent, so that the mechanical property of silicate cement can be remarkably improved.

The invention provides a method for growing an oversized diamond polycrystalline film. The method comprises the following steps: S1, cleaning and drying a monocrystalline silicon wafer at room temperature; s2, carrying out pretreatment seed crystal on the monocrystalline silicon wafer, covering a diamond nanocrystalline layer on the silicon surface, and putting the monocrystalline silicon wafer into MPCVD (Microwave Plasma Chemical Vapor Deposition) equipment; s3, the cavity is vacuumized, then hydrogen is introduced for purging, and then vacuumizing is conducted again; then hydrogen is introduced, the air pressure is regulated and controlled to be 5-8 torr, and starting is started to ignite the plasma; s4, the microwave power is increased to 70 KW to 75 KW at the speed of 4.5 KW / min to 5.5 KW / min, the air pressure is increased to 165 torr to 180 torr at the speed of 10 torr / min to 30 torr / min, and the temperature is increased to 900 DEG C to 950 DEG C at the speed of 60 DEG C / min; s5, introducing growth gas, wherein the flow rate of hydrogen is 5000-6000 sccm, the flow rate of methane is 100-150 sccm, the flow rate of oxygen is 5-8 sccm, the flow rate of nitrogen is 1-2 sccm, and the flow rate of argon is 800-1000 sccm; and S6, after the growth is finished, cooling at a rate of 30 DEG C / min, and introducing nitrogen into the cavity for vacuum breaking until the temperature is reduced to room temperature, so as to obtain the oversized diamond polycrystalline film. The size of the oversized diamond polycrystalline film reaches 12 inches.

The invention discloses a recovery treatment process of heavy metal production wastewater, and relates to the technical field of wastewater treatment. Adjusting the pH value of the wastewater through pretreatment and stirring; 5%-10% of nanometer seed crystals are added in the seed crystal reinforced vulcanization process, a vulcanizing agent is controllably added, and large-particle-size precipitates are generated through pulse stirring; magnetic field separation is performed after magnetic microsphere adsorption; carrying out selective adsorption and acid regeneration on the chitosan-based magnetic resin; micro pollutants are removed through cooperation of the three-dimensional electrode and photocatalysis; concentrating 10-20 times by membrane distillation to enrich heavy metals; metal simple substances with the purity larger than or equal to 99.5% are recycled through pulse electrodeposition; and after deep treatment, the wastewater reaches the standard to be discharged or recycled (the recycling rate is greater than or equal to 70%). The process innovation comprises the steps of enhancing the seed crystal to improve the vulcanization efficiency by 30%, realizing rapid separation by a magnetic material, reducing the energy consumption by 40% by a three-dimensional electrode coupling membrane method, and constructing a vulcanizing agent regeneration (the regeneration rate is greater than or equal to 85%) and heavy metal closed-loop recovery system. Compared with a traditional process, the heavy metal removal rate is larger than or equal to 99.8%, the treatment cost of each ton of water is reduced by 25%-30%, and the method has the advantages of high efficiency, low consumption, environmental protection and recycling and is suitable for multi-metal complex wastewater.

The invention discloses a method and a device for growing a cadmium zinc telluride single crystal, and is characterized in that the method comprises the following steps: (1) putting a cadmium zinc telluride polycrystal ingot into a pyrolytic boron nitride crucible, the cadmium zinc telluride polycrystal ingot is obtained by a preset temperature gradient synthesis method, and has [111] crystal orientation cluster crystal grains in the growth direction; (2) putting the pyrolytic boron nitride crucible into a vacuum closed quartz container, controlling a six-temperature-zone growth furnace through a computer to complete the melting process of a polycrystalline material, and before formal growth, forming a solid-liquid interface distribution structure in which polycrystals are not melted and the rest parts are completely melted at the center of the bottom, wherein the diameter of the solid-liquid interface distribution structure is not less than 30mm; (3) after heat preservation is conducted for a preset time, two-step cooling is achieved in a VGF mode; in the first cooling stage, an initial temperature gradient is formed, and after heat preservation is conducted for a preset time, elimination, merging and growth of [111] crystal nuclei are completed; in the second cooling stage, stable and continuous propulsion of a solid-liquid interface is completed, and continuous growth of single crystals is achieved; and finally, cooling to room temperature to obtain the cadmium zinc telluride single crystal. According to the method, the effect of growing the cadmium zinc telluride crystal with high single crystal rate under the seed crystal-free condition is realized.

The invention provides a silicon carbide crystal growth process which comprises the following steps: A) dividing the interior of a crucible into seven loading areas, namely an F area, a D area, a B area, an A area, a C area, an E area and a G area which are adjacent in sequence by adopting graphite partition plates, filling silicon carbide powder in each loading area, and placing the graphite partition plates perpendicular to the bottom surface of the crucible; the particle size of the silicon carbide powder is 10-80 meshes; and B) fixing a seed crystal on the top of the crucible filled with the silicon carbide powder, and growing the silicon carbide crystal by adopting a PVT method. By optimizing the charging process, the uniformity and the utilization rate of sublimation gas of the powder in the growth process can be improved, the stability of a temperature field in a furnace is facilitated, the probability of crystal phase change is reduced, crystal defects (phase change, polycrystal, dislocation and the like) are reduced, and thus the crystal quality is improved.

A seed substrate for epitaxial growth has a support substrate, a planarizing layer of 0.5 to 3 μm provided on the top surface of the support substrate, and a seed crystal layer provided on the top surface of the planarizing layer. The support substrate includes a core of group III nitride polycrystalline ceramics and a 0.05 to 1.5 μm encapsulating layer that encapsulates the core having surface voids filled and flattened by Al or Si oxide, nitride, oxynitride, or a mixture thereof. The seed crystal layer is provided by thin-film transfer of 0.1 to 1.5 μm of the surface layer of Si <111> single crystal with oxidation-induced stacking faults (OSF) of less than 10 defects / cm2.

The present invention relates to the field of silicon carbide crystal growth, and provides a device and method for growing a high-quality silicon carbide crystal and a silicon carbide crystal. An annular flow guide plate used for guiding a gas-phase crystal growth component to flow to a seed crystal is arranged in the device, and a pressure equalizing structure is arranged on the annular flow guide plate; by arranging the pressure equalizing structure on the annular flow guide plate, the pressure difference between a second chamber above the annular flow guide plate and a first chamber below the annular flow guide plate can be effectively reduced, so that the pressures of the two chambers are close to each other as much as possible, the flow velocity of a gas-phase crystal growth component in a gap between the top end of the annular flow guide plate and the edge of a seed crystal can be effectively reduced, and thus the growth speed of a silicon carbide crystal at the edge of the seed crystal is as same as possible as that of a silicon carbide crystal at the center of the seed crystal, thereby avoiding the defects of a concave interface and the like of a silicon carbide crystal growing on the seed crystal and improving the growth quality of a silicon carbide crystal. The silicon carbide crystal prepared by the method has the characteristics of few defects and high quality.