47results about How to "Lattice integrity" patented technology

The invention provides a preparation method of graphene oxide. The method comprises the following steps: firstly, mixing graphite, an intercalator and an oxidizing agent under an airtight condition and then carrying out a reaction to obtain a reaction mixture; separating the reaction mixture obtained in the previous step to obtain a reaction product; finally, stripping the reaction product, obtained in the previous step, in a dispersing agent to obtain graphene oxide dispersion liquid. According to the preparation method, the intercalator is inserted into the parts among graphene sheet layers under the action of pressure and under the airtight condition, so that the acting force among layers is reduced, and the distances among the layers are increased; then, the oxidizing agent enters the parts among the graphene sheet layers and has an oxidation reaction, so that the graphene oxide is formed; due to the action of the pressure, the intercalator and the oxidizing agent are enabled to enter the parts among graphene layers more rapidly, and the reaction is promoted to be completed within a short time, so that first-order intercalating for the graphite is realized; furthermore, the preparation method is less in energy consumption in a reaction process, environmentally-friendly, convenient and fast to operate as well as safe and controllable, thus being more suitable for industrial mass production.

The invention discloses a P-type heavily-doped silicon carbide film extension preparation method, which mainly solves the problem that in the prior art, high-quality heavy doping of silicon carbide cannot be realized. The method comprises the following steps that: a silicon carbide underlay is firstly placed into a reaction chamber; the reaction chamber is heated in the hydrogen stream, and after the temperature reaches 1,400 DEG C, propane (C3H8) is added into the hydrogen stream; after the temperature reaches 1,580 DEG C, in-situ etching is performed on the underlay for 10 to 30 minutes; then the temperature of the reaction chamber is maintained at 1,580 DEG C, the air pressure is maintained at 100mbar, silane (SiH4) with a flow rate of 15 to 24 mL / min, C3H8 with a flow rate of 5 to 10 mL / min and trimethyl aluminium with a flow rate of 3.2*10<minus 5 mol / min) are added into the hydrogen stream of 20L / min to grow an extension layer; after the growth is completed, the extension layer is cooled in the hydrogen stream; and finally, argon is charged into the reaction chamber to the normal pressure. The doping concentration of the prepared silicon carbide extension layer is 4*1019cm<-3> to 4.6*1019cm<-3>, the doping is uniform, the surface is smooth, and the prepared silicon carbide extension layer can be used for producing a silicon carbide device.

The invention discloses a horizontal growth device and growth method of a phosphorus silicon cadmium mono-crystal, belonging to the technical field of phosphorus silicon cadmium mono-crystal preparation. The device comprises an outer layer quartz tube, an inner layer quartz tube sleeved in the outer layer quartz tube, and a PBN boat-shaped crucible sleeved in the inner layer quartz tube, wherein the PBN boat-shaped crucible comprises a crystal nucleus growth section, a transition section and a mono-crystal growth section which are connected with one another in sequence; a first end part of the crystal nucleus growth section is set to be spire-shaped so as to improve the uniformity of crystal orientation in spontaneous nucleation. By virtue of the design of a double-layer quartz tube, inert gas is introduced between the quartz tubes, so that the problems of tube explosion extremely easily generated in the crystal growth process can be solved, and the stability of a thermal field and the durability of the growth device can be improved. The method is used for preparing the phosphorus silicon cadmium mono-crystal on a horizontal crystal growth furnace with the growth device by using a horizontal gradient freezing method so as to ensure a more stable crystallization process and reduce the defects of parasitic nucleation; the method is beneficial for obtaining a CSP mono-crystal with good mono-crystal performance and complete crystal lattice, and is simple in operation, easy in control and low in cost.

The invention relates to the manufacturing field of light emitting diodes (LED), in particular to a photoluminescent wafer for the LED as well as preparation method and application thereof. The photoluminescent wafer is a slice-shaped crystal in a garnet structure with a general formula of A3B5O12 without doping any resins and other bonding agents, the thickness of the photoluminescent wafer is not less than 20 um, and the size of the crystal particle is not less than 10 um; moreover, the photoluminescent wafer comprises a first element A, a second element B and an active element, wherein thefirst element A is at least one of rare-earth elements Y, Lu, La, Gd or Sm; the second element B is at least one of the elements Al, Ga or In; and the active element is at least one of the rare-earthelements Ce, Pr, Tb and Dy. The photoluminescent wafer has the characteristics of high light emitting efficiency and good light emitting uniformity; the light transmission of the light emitting layercan not be reduced by light adsorption of the bonding agent; and the surface of the photoluminescent wafer is easy for people to carry out various optical treatments.

The invention provides a preparing method of oxidized graphene. The preparing method comprises the following steps that at first, on the condition of pressurization of protective gas, graphite, an intercalator and an oxidizing agent are subjected to low-temperature reaction after being mixed, and a reaction mixture is obtained; then the reaction mixture obtained in the above step is separated, and then a reaction product is obtained; finally, the reaction product obtained in the above step is stripped in a dispersing agent, and oxidized graphene dispersing liquid is obtained. By the adoption of the low-temperature condition, the defect rate is reduced obviously, under the effect of pressure, the intercalator is inserted between graphene sheet layers, the acting force between the layers is reduced, and the distance between the layers is increased; then the oxidizing agent enters the portions between the graphene sheet layers, the oxidizing reaction is carried out, and thus oxidized graphene is formed; and due to the effect of the pressure, the intercalator and the oxidizing agent enter the portions between the graphene sheet layers faster, the reaction is promoted to be more complete within a short time, one-step intercalation to graphene is achieved, and then graphene powder with the low defect rate and high quality is obtained and prepared.

The invention provides a preparation method of a broadband gradient LED (Light-emitting Diode) fluorescent film. The preparation method is characterized in that broadband gradient LED fluorescent powder serves as a raw material; a uniform multicolour (red, green, blue and the like) fluorescent material film is deposited on an LED device or an LED lampshade gasket by a suspension method or a sol-gel method; and the broadband gradient LED fluorescent film prepared by the method has uniform isotropic color temperatures. The preparation method can be used for manufacturing and massively producing high-performance white LEDs with same performance, and can be used for preparing white LED devices, which can emit light approximating to sunlight, with high photoelectric conversion rates and high color rendering indexes. The broadband gradient LED fluorescent powder has a special structure and composition, and is good in dispersity, high in stacking density, great in scattering intensity and high in light-emitting efficiency.

The invention discloses a method for controlling N-type 4H-SiC homogenous epitaxial doping. The method includes steps of placing silicon carbide substrates into a reaction chamber; heating the reaction chamber in hydrogen stream; adding C<3>H<8> into the hydrogen stream after the temperature of the reaction chamber reaches 1400 DEG C; performing in-situ etching on the substrates for 10-30 minutes after the temperature of the reaction chamber reaches 1580 DEG C; keeping the temperature of the reaction chamber at the temperature of 1580 DEG C, keeping the pressure of the reaction chamber within the range of 300mbar-700mbar, adding SiH<4> at a flow rate of 15-24mL / min, C<3>H<8> at a flow rate of 5-10mL / min and N<2> at a flow rate of 2L / min into the hydrogen stream at a rate of 80L / min and growing epitaxial layers; cooling the silicon carbide substrates in the hydrogen stream after the epitaxial layers complete growing; filling argon into the reaction chamber until the pressure of the reaction chamber reaches the normal pressure. The method has the advantages that only the pressure of the reaction chamber is changed, operation is simple and convenient, and the manufactured silicon carbide epitaxial layers are doped uniformly, have smooth surfaces and can be used for manufacturing silicon carbide devices.

The invention provides an LED (light-emitting diode) fluorescent powder with broadband gradient and a preparation method thereof. A single particle of the fluorescent powder sequentially comprises more than three layers of fluorescent materials with the same crystal structure and different chemical components from inside to outside. According to the preparation method, a microwave heating-homogeneous precipitation technology is adopted for preparing several pure phase micro nanoscale or nanoscale fluorescent powders with the same crystal structure and different components, and then the micro-sized fluorescent powder grain is taken as a seed crystal, the micro-sized fluorescent powder grain is mixed with the pure phase micro nanoscale or nanoscale fluorescent powder, epitaxial growth is conducted sequentially step by step at high temperature, or the micro-sized fluorescent power grain is taken as a seed crystal, a mononuclear multilayered shell structure precursor with the same crystal structure and different components is formed through liquid phase coprecipitation, epitaxial growth is conducted sequentially step by step at high temperature, and then the LED fluorescent powder with broadband gradient is obtained through grinding. The LED fluorescent powder with broadband gradient has a special structure and components, good dispersibility, high bulk density, strong scattering intensity, and high luminous efficiency.

The invention discloses a Prussian white material NaxM [Fe (CN) 6] y.zH2O and a preparation method thereof. The preparation method specifically comprises the following steps: mixing sodium ferrocyanide with low-quality water to obtain a solution I; mixing soluble bivalent transition metal salt, organic acid salt and low-quality water to obtain a solution II; and mixing the solution I and the solution II, carrying out a coprecipitation reaction, and supplementing sodium with a reducing inorganic acid sodium salt to obtain the Prussian white material with high sodium content and high crystallinity. The method is beneficial to reducing the manufacturing cost of the Prussian white material, improving the manufacturing efficiency of the Prussian white material and improving the integrity and electrochemical performance of material crystal lattices.

The invention relates to a method for preparing efficient nano ferric oxide drinking water type flocculants, belonging to the technical field of preparation of inorganic nonmetal nano materials. In the invention, the nano alpha-FeOOH flocculant is prepared by a coprecipitation method and the aluminium and silicon doped nano alpha-FeOOH flocculant is prepared through doping and surface modification. Compared with the traditional preparation methods, the method has the following advantages: the method is simple and practical; the nano particle size distribution is uniform; the preparation process flow is short; the method is environment-friendly; the manufacturing cost is low; and the prepared flocculants have higher treatment effects on toxic and harmful pollutants (such as heavy metals, toxic and harmful organic matters and the like), humic acid, chroma and the like.

The invention discloses an anhydrous Prussian white material and a preparation method thereof. The preparation method specifically comprises the following steps: firstly, mixing potassium ferrocyanide with deionized water to obtain a solution I; mixing soluble bivalent transition metal salt, organic acid potassium salt and deionized water to obtain a solution II; then mixing the solution I and the solution II, and carrying out a co-precipitation reaction to obtain a low-crystal-water potassium-based Prussian white material; and carrying out ion exchange reaction in an organic solvent containing sodium salt to obtain the sodium-based Prussian white material without crystal water. The material is used as a sodium ion battery positive electrode and has excellent electrochemical performance.

The invention relates to a doping source flow control N-type heavily-doped silicon carbide film epitaxial making method. The making method comprises the following steps: 1, placing a silicon carbide substrate in a reaction chamber of a silicon carbide CVD apparatus, and vacuumizing the reaction chamber; 2, introducing H2 to the reaction chamber until the pressure in the reaction chamber reaches 100mbar, maintaining the pressure in the reaction chamber unchanged, gradually increasing the H2 flow to 60L / min, and continuously introducing H2 to the reaction chamber; 3, starting a high frequency coil induction heater RF, gradually increasing the power of the heater, and carrying out in situ etching when the temperature of the reaction chamber gradually rises to 1400DEG C; and 4, maintaining the temperature and the pressure unchanged when the temperature of the reaction chamber reaches 1580-1600DEG C, introducing C3H8 and SiH4 to the reaction chamber, introducing highly pure N2 to the reaction chamber as an N-type doping source, stopping the introduction of SiH4, C3H8 and highly pure N2 to the reaction chamber and maintaining for 1min after a first-layer N-type doping layer grows, adjusting the flow of the highly pure N2, and continuously introducing SiH4, C3H8 and the highly pure N2 to the reaction chamber to grow a second-layer N-type doping layer.

The invention discloses a manufacture method of a through hole. The method comprises the steps that 1 the opening of the through hole is formed in a substrate; 2 a SIP process is used to form a firstbarrier layer formed by superimposing a Ti layer and a first TiN layer; 3 a second barrier layer composed of a second TiN layer is formed; and 4 metal tungsten deposition is carried out to completelyfill the opening of the through hole. According to the invention, the film-forming quality of the barrier layers can be improved; tungsten residues are prevented; and the integrity of the product structure is improved.

The invention relates to a method for preparing a base-region graded doped silicon carbide thin film epitaxy layer. The method comprises the steps that 1, a silicon carbide substrate is placed in a reaction chamber of silicon carbide CVD equipment, and the reaction chamber is vacuated; 2, H2 is introduced into the reaction chamber till the air pressure of the reaction chamber reaches 100 mbar, the air pressure of the reaction chamber is kept constant, the flow of H2 is gradually increased to 60 L / min, and gas continues to be introduced into the reaction chamber; 3, a high-frequency coil induction heater RF is started, the power of the heater is gradually increased, and when the temperature of the reaction chamber gradually rises to 1,400 DEG C, in-situ etching is carried out; and 4, when the temperature of the reaction chamber reaches 1,580 DEG C to 1,600 DEG C, the temperature and pressure are kept constant, the flow of an Al source is set, C3H8 and SiH4 are introduced into the reaction chamber, and the P-type graded doped silicon carbide thin film epitaxy layer is slowly grown by gradually adjusting the flow of the Al source introduced into the reaction chamber. According to the method, the CVD equipment of silicon carbide is utilized, the silicon carbide epitaxy layer with the controllable longitudinal doping concentration gradient is prepared, and the requirement for preparation of the gradient low-doped epitaxy layer is met.

The invention provides a method for removing residual lithium from lithium transition metal oxide and application of the method. The method comprises the following steps: coating lithium transition metal oxide with a lithium absorbing agent, and carrying out heat treatment to form an amorphous surface layer; the amorphous surface layer is converted into a crystalline surface layer through crystallization treatment; the lithium absorbing agent comprises an amorphous substance. The method at least has the following beneficial effects that after the lithium transition metal oxide is coated with the amorphous substance, the amorphous substance has a very strong tendency of combining residual lithium under a heat treatment condition, the content of the residual lithium on the surface of the material can be greatly reduced, and meanwhile, the capacity reduction caused by lithium loss is avoided by absorbing the residual lithium on the surface; and then the amorphous state is converted into the crystalline state, so that crystal lattices are more complete, and the problem that the surface structure of the material is damaged due to energy release in the process of converting the amorphouslong-range disordered metastable state into the crystalline state and the resulting problem of battery attenuation are avoided; therefore, the electrochemical performance of the material is effectively ensured not to be reduced due to elimination of residual lithium on the surface.

The invention provides a preparation method of a powder type high-capacity titanium-based lithium ion exchanger, wherein the titanium source is metatitanic acid on a sulfuric acid process production line, and the precursor can be prepared at low lithium source consumption and short calcination time. The lithium ion elution process of a precursor comprises stirring and adding acid to remove lithiumin a tank, that concentration of slurry H+ in the tank is controlled to prevent the dissolution of titanium, the dissolved lithium is concentrated in a solution, the solid and liquid are separated toobtain a lithium solution with high concentration and low acidity, the concentration energy consumption is reduced and alkali for neutralizing waste acid is reduced, thereby greatly reducing production cost.

The invention discloses a cobalt-free positive electrode material, a preparation method thereof and a lithium ion battery. The molecular formula of the cobalt-free positive electrode material is Li1 + nNixMnyMzO2, wherein x + y + z = 1, 0.5 < = x < 1.0, 0 < y < 0.5, 0 < = z < = 0.1,-0.1 < = n < = 0.5; m is one or more of Al, Mg, Sr, Ti, Fe, Sc, V, Y, Zr, Nb and Mo except Co. The preparation method comprises the following steps: mixing raw materials including a nickel source, a manganese source, a lithium source, an M source, a nucleating agent graphene oxide hydrogel, a precipitator and a complexing agent to prepare a mixed solution, and applying a microwave field in the hydrothermal process of the raw material mixed solution; performing hydrothermal reaction in a protective atmosphere to obtain a positive electrode material process sample; and sintering the process sample in an oxygen-containing atmosphere to obtain the cobalt-free positive electrode material. According to the preparation method, the material performance is improved by regulating and controlling the microstructure and optimizing the preparation process, meanwhile, the cost is saved, and the manufacturing process is simplified; the lithium battery prepared from the cobalt-free positive electrode material has excellent chemical stability and electrical performance.

The invention discloses a production process of iron ion graphene based on a multiphase quantum self-coupling reaction, wherein the production process includes the following steps: firstly, successively inputting a graphite powder and non-ionic auxiliary agents into a powder stirrer and a spiral ribbon screw conical mixer, and fully mixing the three materials, to obtain a mixture A; then, transporting the mixture A to a quartz tube which can perform repeated heating and cooling, and carrying out repeated heating and cooling treatment; next, inputting the mixture A, a chelating wetting agent, acomprehensive impact agent and deionized water into a liquid stirrer, and fully mixing to obtain a mixture B; then carrying out self-coupling reaction of the completely and evenly mixed mixture B ina multiphase quantum self-coupling reaction cylinder; and finally, transporting the final mixture having the self-coupling reaction completed into a vacuum degasser, vacuumizing, and then storing theproduct in a slurry storage cylinder. The high-purity graphene is non-oxidized graphene, and can be directly dispersed and applied.

The invention relates to a method for preparing a P-type lightly-doped silicon carbide thin film epitaxy by controlling hydrogen flow. The preparation method comprises the following steps: (1) placing a silicon carbide substrate into a reaction chamber of silicon carbide CVD (Chemical Vapor Deposition) equipment, and vacuumizing the reaction chamber; (2) introducing H2 into the reaction chamber till the air pressure of the reaction chamber reaches 100 mbar, keeping the air pressure of the reaction chamber constant, then gradually increasing the H2 flow to 60 L / minute, and continuously introducing the H2 into the reaction chamber; (3) starting a high-frequency coil induction heater RF, greatly enhancing the power of the high-frequency coil induction heater RF, and etching in situ when the temperature of the reaction chamber is gradually increased to 1400 DEG C; and (4) when the temperature of the reaction chamber reaches 1580-1600 DEG C, keeping the temperature and pressure constant, introducing C3H8 and SiH4 into the reaction chamber, placing liquid trimethyl aluminum used as a doped source into a bubbler, and introducing a certain amount of H2 into the bubbler so that the H2 carried with the trimethyl aluminum is introduced into the reaction chamber.

The invention discloses a ternary cyano framework material as well as a preparation method and application thereof. The structural general formula of the ternary cyano framework material is AnMnxFeyNiz[Fe(CN)6]m, in the formula, A is selected from one or more of Na<+>, K<+> and NH4<+>, 1.5<n<=2, 0.8<m<=1, 0.4<=x<=0.6, 0.2<=y<=0.4, 0.1<=z<=0.3, and x+y+z=1. The preparation method comprises the following steps: mixing ferrous cyanide with deionized water to obtain a solution I; mixing soluble bivalent manganese salt, iron salt, nickel salt, inorganic acid salt, organic acid salt and deionized water to obtain a solution II; and adding the solution I into the solution II, and carrying out coprecipitation reaction to obtain the ternary cyano framework material. The ternary cyano framework material is coupled with three elements of manganese, iron and nickel, has high working voltage, high capacity, excellent rate capability and cycling stability, and has excellent comprehensive performance.

The invention relates to a method for preparing single crystal wide-band gradient LED phosphor. The method comprises preparing multiple types of pure-phase nanometer fluorescent powder with the same crystal structure and different compositions through a homogenous precipitation method, adding a dispersant, an adhesive and a fluxing agent into the nanometer fluorescent powder, preparing size-controllable spherical particles with different sizes through a granulation method, preparing spherical nano-aggregates with mesoporous structures through a rapid sintering process, carrying out sintering at a high temperature to obtain size-controllable single-crystal phosphor seed crystals, mixing micron-level phosphor crystals as seeds and the pure-phase nanometer fluorescent materials with the samestructure and different compositions, and orderly carrying out epitaxial growth at a high temperature step by step to obtain wide-band gradient LED phosphor. The wide-band gradient LED phosphor has controllable sizes, good dispersity, complete crystal lattice, high packing density, emission frequency wider than that of general phosphor, large scattering intensity and high luminous efficiency.

The Prussian white composite material comprises an inner core and a carbon coating layer coating at least one part of the outer surface of the inner core, the general formula of the inner core is NaxMn1-yMy [Fe (CN) 6] z, M is selected from at least one of Fe, Co, Ni, Cu and Zn, x is larger than 1.5 and smaller than or equal to 2, y is larger than 0 and smaller than or equal to 0.3, and z is larger than 0.8 and smaller than or equal to 1. The Prussian white composite material provided by the invention is free of crystal water (including interstitial water and complexing water), has complete crystal lattices, has good ionic conductivity and thermal stability, and is almost not decomposed at 500 DEG C. The preparation method disclosed by the invention has the advantages of simple process, low cost, short period, low energy consumption and suitability for industrial production.

The invention discloses a horizontal growth device and growth method of a phosphorus silicon cadmium mono-crystal, belonging to the technical field of phosphorus silicon cadmium mono-crystal preparation. The device comprises an outer layer quartz tube, an inner layer quartz tube sleeved in the outer layer quartz tube, and a PBN boat-shaped crucible sleeved in the inner layer quartz tube, wherein the PBN boat-shaped crucible comprises a crystal nucleus growth section, a transition section and a mono-crystal growth section which are connected with one another in sequence; a first end part of the crystal nucleus growth section is set to be spire-shaped so as to improve the uniformity of crystal orientation in spontaneous nucleation. By virtue of the design of a double-layer quartz tube, inert gas is introduced between the quartz tubes, so that the problems of tube explosion extremely easily generated in the crystal growth process can be solved, and the stability of a thermal field and the durability of the growth device can be improved. The method is used for preparing the phosphorus silicon cadmium mono-crystal on a horizontal crystal growth furnace with the growth device by using a horizontal gradient freezing method so as to ensure a more stable crystallization process and reduce the defects of parasitic nucleation; the method is beneficial for obtaining a CSP mono-crystal with good mono-crystal performance and complete crystal lattice, and is simple in operation, easy in control and low in cost.

The invention relates to a hydrogen flow control N-type low-doped silicon carbide film epitaxial making method. The making method comprises the following steps: 1, placing a silicon carbide substrate in a reaction chamber of a silicon carbide CVD apparatus, and vacuumizing the reaction chamber; 2, introducing H2 to the reaction chamber until the pressure in the reaction chamber reaches 100mbar, maintaining the pressure in the reaction chamber unchanged, gradually increasing the H2 flow to 60L / min, and continuously introducing H2 to the reaction chamber; 3, starting a high frequency coil induction heater RF, gradually increasing the power of the heater, and carrying out in situ etching when the temperature of the reaction chamber gradually rises to 1400DEG C; and 4, maintaining the temperature and the pressure unchanged when the temperature of the reaction chamber reaches 1580-1600DEG C, introducing C3H8 and SiH4 to the reaction chamber, introducing highly pure N2 to the reaction chamber as an N-type doping source, stopping the introduction of SiH4, C3H8 and highly pure N2 to the reaction chamber and maintaining for 1min after a first-layer N-type doping layer grows, reducing the H2 flow from 60L / min to 40L / min, and continuously introducing SiH4, C3H8 and the highly pure N2 to the reaction chamber to grow a second-layer N-type doping layer.

A synthesis method of lithium ion battery cathode nano-powder by strengthening solid-phase reaction comprises the steps of: (1) nanocrystallization treatment on a raw material powder; (2) synthesis of a target product compound nano-powder; and (3) lattice complete treatment of synthesis product. The invention uses conventional carbonate meal as a raw material, employs strengthening solid phase thermal decomposition and diffusion reaction to directly and rapidly synthesize the nano-powder. The production process has the advantages of simpleness, short cycle, high efficiency, low energy consumption and no pollution, and is applicable to continuous production; the solid phase reaction process is complete; the powder has fine size, and uniform composition and particle size; and the synthetic product does not require subsequent pulverization treatment; and the powder has complete lattice and shows good electrochemical performance.

The invention relates to the field of desulfurizing agents, and specifically relates to a desulfurizing agent for removing hydrogen sulfide. The desulfurizing agent is prepared from the following raw materials in parts by weight: 70-90 parts of nanoscale zinc ferrite, 5-20 parts of a binder, and 5-10 parts of a transition metal accelerant; the desulfurizing agent, prepared from the nanoscale zinc ferrite, the binder and the transition metal accelerant according to a certain ratio, is compact in atomic arrangement and stable in crystal form, therefore the prepared desulfurizing agent has the advantages of high mechanical strength, little possibility of active component loss and good water resistance, and the hydrogen sulfide content in ammonia gas can be reduced to 0.01 mug / g or below, thereby meeting the sulfur-containing requirements of liquid ammonia for chemical industry and environmental protection.

The invention relates to an epitaxial preparation method of a P type heavily-doped silicon carbide film by controlling a flow rate of a hydrogen gas. The preparation method comprises the following steps: (1) placing a silicon carbide substrate into a reaction chamber of silicon carbide CVD (chemical vapor deposition) equipment, and vacuating the reaction chamber; (2) introducing H2 into the reaction chamber until the gas pressure of the reaction chamber reaches 100mbar, keeping the gas pressure of the reaction chamber constant, gradually increasing the flow rate of the H2 to 60 L / min, and continuously introducing H2 into the reaction chamber; (3) switching on a high-frequency coil induction heater RF, gradually increasing the power of the heater, and carrying out in-situ etching when the temperature of the reaction chamber is greatly increased to 1400 DEG C; and (4) keeping the temperature and the pressure intensity constant while the temperature of the reaction chamber is 1580-1600 DEG C, and introducing C3H8 and SiH4 into the reaction chamber; placing liquid-state trimethyl aluminum into a bubbler as a doping source, introducing a certain amount of H2 into the bubbler and introducing the H2 into the reaction chamber along with the trimethyl aluminum.

The invention relates to a method for synthesizing polycrystalline diamond by retorting plant straw detonation. The retort plant straw is mixed with high-energy explosive 8701 to make a powder column, and the retort plant straw is phase-transformed into polycrystalline diamond by using the high temperature and high pressure conditions generated at the instant of explosive explosion, and The detonation ash produced by the explosion is chemically purified by the sequential combined oxidation reaction of concentrated sulfuric acid and perchloric acid to remove graphite, amorphous carbon and metal impurities in the detonation ash, and then separated by sedimentation, washed and dried to obtain pure polycrystalline diamond. . Its performance was characterized by XRD phase analysis. Compared with graphite and carbon source, polycrystalline diamond with larger grain size and more complete crystal lattice was obtained by using retort plant straw as an external carbon source, which has better performance. Indicators are also more valuable in actual production applications.

The invention relates to a preparation method of high-temperature resistant red fluorescent powder for CCFL (cold cathode fluorescent lamp), belonging to the technical field of preparation for luminescent materials. The preparation method comprises the following steps: dissolving urea in water to obtain urea solution; performing classification process to ytterbium europium oxide and controlling particle size of the ytterbium europium oxide to obtain first powders; adding the first powders into a stirring container filled with deionized water and stirring to obtain first slurries; cleaning the first slurries with the deionized water, sieving, and removing clear liquids after precipitating to obtain second slurries; adding the urea solution into the second slurries and stirring to obtain first mixtures; standing and precipitating the first mixtures, then pouring and removing the clear liquids to obtain second mixtures; dehydrating and drying the second mixtures, and sieving to obtain to-be-baked raw materials; putting the to-be-baked raw materials into the container and conveying into furnaces to bake, taking out of the furnaces and cooling to obtain the finished products. Lattices are completer; particles are more uniform; surface coating effects are excellent; heat stability is ideal; radiation resistance and aging resistance are excellent.

The invention provides an LED (light-emitting diode) fluorescent powder with broadband gradient and a preparation method thereof. A single particle of the fluorescent powder sequentially comprises more than three layers of fluorescent materials with the same crystal structure and different chemical components from inside to outside. According to the preparation method, a microwave heating-homogeneous precipitation technology is adopted for preparing several pure phase micro nanoscale or nanoscale fluorescent powders with the same crystal structure and different components, and then the micro-sized fluorescent powder grain is taken as a seed crystal, the micro-sized fluorescent powder grain is mixed with the pure phase micro nanoscale or nanoscale fluorescent powder, epitaxial growth is conducted sequentially step by step at high temperature, or the micro-sized fluorescent power grain is taken as a seed crystal, a mononuclear multilayered shell structure precursor with the same crystal structure and different components is formed through liquid phase coprecipitation, epitaxial growth is conducted sequentially step by step at high temperature, and then the LED fluorescent powder with broadband gradient is obtained through grinding. The LED fluorescent powder with broadband gradient has a special structure and components, good dispersibility, high bulk density, strong scattering intensity, and high luminous efficiency.