218results about "From melt solutions" patented technology

The invention discloses a method for preparing hexagonal boron nitride by adding seed crystals, and relates to the field of boron nitride materials, the hexagonal boron nitride with two scales of nanoscale and micron scale is prepared at a relatively low temperature of 1100-1600 DEG C by adopting a molten salt method and adding the seed crystals, and the method has important significance for producing high-quality h-BN single crystals with different sizes. The operation difficulty is low, the energy consumption is low, the cost is saved, and large-scale production is easy.

The invention discloses a method for low-temperature synthesis of an ultra-high nickel single crystal positive electrode material based on a molten salt fluxing agent method, which comprises the following steps: mixing an ultra-high nickel precursor with the nickel content of more than or equal to 90% with a lithium source according to a stoichiometric ratio, then adding a certain mass of sodium chloride (NaCl) as a fluxing agent medium, and fully grinding; the mixed material is subjected to temperature programming sintering in an oxygen-containing atmosphere, and the highest sintering temperature is controlled between 700 DEG C and 850 DEG C; and cooling, washing, drying and sieving the sintered product to finally obtain the small-size ultrahigh-nickel single-crystal positive electrode material with good dispersity. By introducing the low-melting-point molten salt fluxing agent, the growth temperature of the single crystal is remarkably reduced, lithium volatilization and abnormal growth and agglomeration of crystal grains are effectively inhibited, and the obtained single crystal particles are uniform in size (2 microns) and have a good layered structure and electrochemical performance. The method is simple in process, low in cost and suitable for large-scale production of the ultrahigh-nickel single-crystal positive electrode material for the high-performance lithium ion battery.

The invention relates to a novel second-order nonlinear optical crystal-potassium cadmium germanate (K4Cd3Ge4O13), and belongs to the field of optical crystal materials. The crystal is prepared by adopting a high-temperature solid-phase method and a high-temperature solution method, belongs to an orthorhombic crystal system and a C2 space group, is accurate in measurement of cell parameters, and shows excellent nonlinear optical characteristics and a wide light transmission range. The ultraviolet cut-off edge of the crystal is 261 nm, the infrared spectrum permeability is not obviously reduced in the range of 4000-714 cm <-1 >, the transmission range of the crystal can effectively cover a key atmosphere transmission window of 3-5 microns, and the crystal has powder frequency doubling response equivalent to that of a KDP crystal and can be applied to an all-solid-state laser as a mid-infrared nonlinear optical crystal.

Semiconductor substrate of a nitride of a group III element, comprising: a first surface; and a second surface where the distortion of a crystal plane of the first surface exhibits a multitude of extremes.

The application discloses a zinc oxide whisker heating furnace and a control method thereof, and belongs to the field of zinc oxide whisker production equipment. The zinc oxide whisker heating furnace comprises a furnace body, a whisker collecting groove and a lifting mechanism connected with a furnace cover. A zinc wire winding mechanism is rotatably connected to the furnace cover. The top end of a connecting rod of the whisker collecting groove is provided with a clamping groove, and the middle part is provided with an annular groove. A silicon carbide connecting rod is connected to the zinc wire winding mechanism, and the silicon carbide connecting rod is matched with the clamping groove. A rotating table is fixedly connected to a supporting frame. The rotating table is fixedly provided with a first electric telescopic mechanism extending towards the furnace body. The first electric telescopic mechanism is fixedly connected with a second electric telescopic mechanism. The second electric telescopic mechanism is connected with a clamping jaw matched with the annular groove. A controller is connected with the lifting mechanism, the rotating table, the first electric telescopic mechanism and the second electric telescopic mechanism. The scheme can realize automatic taking out and installation of the whisker collecting groove, and manual taking out with the aid of tools or waiting for the whisker collecting groove to cool down is not needed, so that the safety of zinc oxide whisker production is ensured.

The invention belongs to the technical field of nonlinear optical crystals, and particularly relates to a zeolite-like structure nitrogen oxide silicate nonlinear optical crystal and a preparation method and application thereof, the chemical general formula of the crystal is Ba3Si3N5OCl, the crystal belongs to a hexagonal system, the cell parameters of the crystal are as follows: a is 9.5147 (6), c is 5.5002 (4), V is 431.22 (6) 3, Z is 2, the space group is P-62c, and the crystal has a non-centrosymmetric structure. The Ba3Si3N5OCl crystal provided by the invention is used as a novel zeolite-like structure nitrogen oxide silicate, successfully integrates nonlinear optical activity and phase matching capability, can generate frequency doubling response which is about 0.2 times of KDP (potassium dihydrogen phosphate) under 1064 nm laser pumping, and can realize phase matching, so that the Ba3Si3N5OCl crystal becomes a nonlinear optical material with practical device application potential.

The invention relates to the technical field of heat-insulating and demagnetizing refrigeration, and discloses a heat-insulating and demagnetizing refrigeration material based on a Trellis crystal lattice and a preparation method and application of the heat-insulating and demagnetizing refrigeration material. The chemical formula of the heat insulation and demagnetization refrigeration material based on the Trellis crystal lattice is Gd2GeB2O8. A magnetic test result of the Gd2GeB2O8 crystal shows that the magnetic anisotropy of the crystal material is relatively weak and tends to magnetic isotropy, and a long-range magnetic orderliness phenomenon is not observed above 1.8 K. And when adiabatic demagnetization is carried out under initial conditions that T is equal to 3K and B is equal to 7T, the material can reach the maximum negative magnetic entropy difference of 51.68 J * kg <-1 > * K <-1 >, which shows that the Gd2GeB2O8 has a better application prospect in a 3-17K temperature zone and a sub-Kelvin temperature zone.

The present invention relates to a rubidium fluoro-scandium borate compound, a rubidium fluoro-scandium borate nonlinear optical crystal, and a preparation method and application thereof. The rubidium fluoro-scandium borate compound has a chemical formula Rb2ScB3O6F2, does not contain a symmetry center and has a molecular weight of 382.33 g / mol. The rubidium fluoro-scandium borate nonlinear optical crystal belongs to the monoclinic crystal system, and belongs to the non-centrosymmetric space group P21, and the unit cell parameters are: a=4.0372(10) Å, b=11.800(3) Å, c=8.823(2) Å, α=γ=90°, β=98.327(11)°, Z=2. The present invention adopts a high-temperature vacuum packaging method or a solid-state synthesis method to prepare rubidium fluoro-scandium borate compounds. The present invention adopts a fluxing agent method to prepare a rubidium fluoro-scandium borate nonlinear optical crystal, which have the advantages of short absorption cutoff edge, large nonlinear optical effect, good thermal stability, and stable physical and chemical properties. The rubidium fluoro-scandium borate nonlinear optical crystal of the present invention can be used to fabricate nonlinear optical devices, which have important applications in fields such as optics, military, laser lithography, and communication, etc.

The invention provides a layered Van der Waals material with full-compensation ferrimagnetism and a topological Hall effect as well as a preparation method and application of the layered Van der Waals material. The chemical formula of the material is MnxCrTe2, wherein 0 lt; and x is 1. The material provided by the invention has a wide compensation temperature range, a large magnetoresistance effect, anisotropy and a topological Hall effect, is a CrTe2 intercalation ferromagnetic material doped in different proportions, and can realize optimization and continuous adjustability of performances such as magnetism, Curie temperature and Hall parameters of the material through regulation and control of mechanisms such as the doping proportion, the temperature and the magnetic field; and a material basis is provided for researching the application of the Mn intercalation CrTe2 crystal material in the field of magnetic induced storage.

The invention belongs to the technical field of hexagonal boron nitride single crystal growth, and discloses a reusable crucible for growing a large-size hexagonal boron nitride single crystal, which comprises a crucible main body, a crucible upper half part and a crucible lower half part, and the crucible upper half part and the crucible lower half part are fixed by a connecting structure; the upper half part of the crucible is in a straight cylinder shape; the inner wall of the lower half part of the crucible is a combination of an inverted circular truncated cone-shaped inner wall and a straight cylinder-shaped inner wall; and the crucible cover is arranged on the surface of the upper half part of the crucible. According to the invention, the crucible is designed into a separated structure, and the upper half part of the crucible is detachable and can be repeatedly used; the inner wall of the bottom of the crucible at the lower half part is designed into an inverted circular truncated cone-shaped structure, so that the transverse corrosion of a fluxing agent to the inner wall of the crucible can be reduced, the metal cast ingot and the hexagonal boron nitride single crystal on the surface of the metal cast ingot can be taken out of the crucible more easily, and the crucible can be repeatedly used; meanwhile, the structure can reduce the flow velocity of the fluxing agent on the growth surface, weaken the vortex at the bottom of the fluxing agent in the growth process and improve the growth quality of the hexagonal boron nitride crystal.

This invention discloses a barium borate crystal, its preparation method, and its applications. The barium borate crystal has the chemical formula Ba₂BeB₂O₆, a non-centrosymmetric structure, belongs to the orthorhombic crystal system, has the space group Pca₂₁, and its cell parameters are α = 90°, β = 90°, and γ = 90°. This barium borate crystal exhibits extremely low birefringence from the ultraviolet to the infrared band, and its extremely low birefringence supports its application on zero-order glass slides.

The invention relates to the technical field of beta-Ga2O3 crystal material growth, in particular to a fluxing agent of a beta-Ga2O3 crystal and a preparation method of a single crystal X-ray detector of the fluxing agent. A fluxing agent for growing the beta-Ga2O3 crystal comprises tellurium oxide and divalent alkaline earth metal carbonate. Uniformly mixing gallium oxide and a fluxing agent to obtain a mixed material; transferring the mixed material into a crystal growth furnace, and heating to melt the mixed material to obtain a melt; and cooling the melt to 0.5-3 DEG C above the saturation point temperature, putting a seed crystal into the melt, cooling to enable the crystal to grow, taking out the crystal after the growth is finished, and cooling to room temperature to obtain the beta-Ga2O3 crystal. The fluxing agent provided by the invention does not contain toxic components such as lead, fluorine and the like, the crystal growth temperature range of the fluxing agent is approximately 780-850 DEG C, the growth temperature of the crystal is effectively reduced, the volatilization of a melt at a high temperature is reduced, the deviation and viscosity of solution components are reduced, the corrosion to a platinum crucible is reduced, and the beta-Ga2O3 crystal with high quality and large size is easy to obtain.

To provide a garnet-structured aluminate scintillating material doped with a transition metal element having an ionic radius and electronegativity similar to Al3+, and an outer electron configuration of [Ar]3dn4s1-2 (n≥5), as well as a preparation method and application thereof.SOLUTION: The chemical formula of the transition metal element doped garnet-structured aluminate scintillating material is RE3-x-aCexAaAl5-y-zDyMzO12, wherein x is 0<x≤0.15, y is 0≤y≤3, z is 0<z≤0.1, and a is 0≤a≤0.1; the rare earth element RE is at least one selected from Gd, Lu, Y, Sc, La, Nd, Eu, Tb, Dy, Ho, Er, Tm, and Yb, the A is at least one selected from Li, Mg, Ca, K, and Na, the D is at least one selected from Ga and In, and the M is a transition metal element, which is at least one selected from Cr, Mn, Fe, Co, and Ni.SELECTED DRAWING: Figure 1

The invention provides a lead titanium tellurate second-order nonlinear optical crystal and a preparation method and application thereof, and belongs to the technical field of optical crystal materials. The compound is prepared by a solid-phase synthesis method and a fluxing agent method, and the preparation method comprises the step of growing the titanium lead tellurate nonlinear optical crystal by adopting the fluxing agent method. The obtained product has the advantages of large frequency-doubled effect, large optical band gap, wide transmission range, stable physical and chemical properties and difficulty in deliquescence, and can be used for preparing near-intermediate infrared nonlinear optical frequency conversion devices.

The application provides a niobium phosphate nonlinear optical crystal and preparation and application thereof. 12 Nb3P7O 31 , belongs to an orthorhombic system, a space group is Pna21, is a non-central symmetric structure, cell parameters are: a=0.5 nm, b=1.0 nm, c=0.5 nm, and Z=4, has a large nonlinear optical effect (3xKDP), is phase-matched, a theoretical indirect band gap is 5.11 eV, has a large laser damage threshold, a wide transmission range, stable physical and chemical properties, good mechanical properties, is not easy to deliquesce, and is easy to preserve, and can be used as a ferroelectric crystal, a pyroelectric crystal or a laser substrate material, and is widely applied in preparation of middle infrared laser nonlinear optical composite functional devices, piezoelectric devices, laser frequency conversion devices and the like.

A single crystal diamond material comprising a single crystal diamond and an altered portion present on the outer periphery of the single crystal diamond, wherein the nitrogen atom content in the single crystal diamond is 1 ppm or more and 2000 ppm or less based on the atomic number, and the single crystal diamond material has a core electron excitation spectrum of the altered portion obtained by electron energy loss spectroscopy using a transmission electron microscope, in which an energy loss of π exists in a range of 285 eV±5 eV. * Maximum intensity of the peak Iπ * and the energy loss is in the range of 291±5 eV. * Maximum intensity of the peak Iσ * Ratio to Iπ * / Iσ * is 0.15 or more, and in the altered portion, the percentage {N1 / (N1+N2)}×100 of the number N1 of primary carbon atoms to the sum N1+N2 of the number N1 of primary carbon atoms constituting amorphous carbon and the number N2 of secondary carbon atoms constituting graphite is 90% or more.

The application provides a mass production method for an intermediate valence state vanadium oxide electronic phase change powder and single crystal, belongs to the field of heat-sensitive electronic phase change materials, and particularly relates to a method for realizing mass production of high-purity and high-uniformity polycrystalline or single crystal materials in a precisely controlled atmosphere by using an additive with the dual effects of fluxing agent and heterogeneous seed crystal, fully dissolving a precursor required for synthesizing the system material by means of a molten alkali halide fluxing agent, and fully reacting the precursor in the process, so as to greatly reduce the reaction temperature and reaction time required for material synthesis, realize mass production of the materials in the precisely controlled atmosphere, and continuously regulate the metal insulator transition temperature of the materials in a wide range by further regulating the valence of vanadium in the intermediate valence state vanadium oxide, the type of doped elements and the doping ratio, so that the method has certain application prospects in the fields of strong light protection, infrared camouflage, thermochromism and sudden change type thermistor devices.

The application provides a fluorinated guanidinium borate nonlinear optical crystal and a preparation method and application thereof. The chemical formula of the crystal is [C(NH2)3]B6O9F, the molecular weight is 287.95, the crystal belongs to an orthorhombic system, the space group is Pnma, Pna 21, the cell parameter is a=7.8420(11) Å, b=15.1862(19) Å, c=8.5762(9) Å, α =90°, β =90°, γ =90°, the unit cell volume is 1021.3(2) ų, the crystal is grown by a high-temperature solution method or a flux method, the frequency doubling effect of the crystal is 0.4 times of that of KH2PO4 (KDP), the ultraviolet cutoff edge is 190 nm, the birefringence is large, the birefringence is 0.133 @ 1064 nm, and the deep ultraviolet phase matching capability is deep, the shortest matching wavelength is 196 nm, and the crystal can be applied to deep ultraviolet nonlinear optical crystals in a full solid-state laser.

The invention belongs to the technical field of preparation of high-performance thermoelectric materials, and particularly relates to a method for assisting in optimizing a P-type tin telluride thermoelectric material grain boundary and defect structure through fused salt. The polycrystalline SnTe material is synthesized by adopting a molten salt medium auxiliary melting method. According to the method, directional attachment in the crystal growth process can be promoted in a high-temperature liquid phase environment, large-size crystal grains are formed, the density of large-angle crystal boundaries is remarkably reduced, meanwhile, a sub-crystal structure composed of small-angle crystal boundaries is formed in the crystal grains through induction, the carrier mobility is improved, and the electron transport performance is optimized. Besides, cation vacancy defects are introduced by regulating and controlling a reaction environment and a doping strategy, so that the carrier concentration can be effectively regulated, and the Seebeck coefficient is further improved. On the basis, multi-scale interface scattering can be further realized and the lattice thermal conductivity can be obviously reduced by compounding an exogenous nano structure such as Mg2Yb, and finally collaborative optimization of the electric heating performance is realized, so that the material obtains excellent thermoelectric performance in a wide temperature range.

The application belongs to the technical field of crystal growth, and particularly relates to a SiC single crystal growth method by means of a dissolving agent. The method comprises the following steps: mixing high-purity silicon, metal chromium and metal cobalt, placing the mixture in a graphite crucible or a SiC crucible, heating and smelting under an inert atmosphere or a hydrogen-containing mixed atmosphere, forming a Si-Cr-Co alloy, controlling the Cr content in the alloy to be less than or equal to 60 at.%, the Co content in the alloy to be less than or equal to 20 at.%, and the balance being Si, continuously increasing the temperature to not less than 1800 DEG C, dissolving carbon in the alloy to obtain a Si-Cr-Co-C melt saturated with SiC and carbon, and then growing a SiC single crystal in the melt by means of a top-seed solution growth method or a crucible lowering method. The application introduces cobalt to cooperate with chromium, thereby improving the carbon solubility, inhibiting the aggregation of crystal surface steps, and reducing the doping concentration of the dissolving agent elements in the crystal.

The invention relates to a method for growing a terbium lithium fluoride magneto-optical crystal by using a fluxing agent. The process comprises the following steps: (1) fully mixing a fluxing agent with raw materials; (2) putting the mixture into a crucible, feeding the crucible into a high-temperature molten salt furnace, vacuumizing the furnace, and introducing protective gas; and (3) controlling the heating rate, heating until the mixture is completely molten, and keeping the temperature for several hours. And (4) slowly cooling until crystals are completely separated out. And (5) annealing to room temperature to obtain the terbium lithium fluoride crystal. Tests show that the terbium lithium fluoride crystal prepared by the method is good in quality, large in extinction ratio and high in damage threshold, has relatively high transmittance and relatively strong magneto-optical performance in wave bands of 505nm, 633nm, 880nm and 1064nm, and is expected to be practically applied to magneto-optical devices such as magneto-optical isolators, Faraday rotators and the like.

The invention discloses a growth formula and a growth method of an easy-to-peel hBN single crystal. The formula comprises the following components: a specific metal solvent material, a precursor material, a reducing agent material and shielding gas. A Fe-Ni-Cr ternary metal solvent with a specific proportion is adopted, and a BN powder isolation layer is formed under hBN crystals in an induction mode. According to different formula parameters, in combination with a specially designed three-section program cooling strategy, controllable growth of the hBN crystal size and the powder isolation layer thickness is realized. Through the protection of the BN powder isolating layer, an operator can peel the hBN crystal along the interface of the isolating layer by using a hard medium (such as a blade) without directly contacting the crystal, so that the mechanical damage to the hBN crystal in the peeling process is effectively avoided. The method ensures that the grown hBN crystal can be completely stripped from the surface of the metal ingot, and finally the large-area hBN single crystal with complete structure and considerable thickness is obtained.

The present application relates to the technical field of cold storage. Specifically disclosed are a cold storage material, and a preparation method therefor and the use thereof. The cold storage material comprises a Gd2O2Se crystal. The cold storage material in the present application comprises the Gd2O2Se crystal, and the Gd2O2Se crystal has a phase transformation near 6.22 K, a relatively large specific heat in a temperature range of 1-10 K, and an obvious magnetothermal effect and can be used as a cold storage material at a liquid helium temperature.

This application discloses a diamond-like carbon (DLC) crystal material, its preparation method, and its application as an infrared nonlinear optical material, belonging to the field of crystal preparation technology. The DLC crystal material has a triclinic structure with the chemical formula AM5Q8; wherein A is selected from at least one of Na, K, Rb, and Cs; M is selected from at least one of Ga and In; and Q is selected from at least one of S, Se, and Te. This crystal material exhibits a frequency doubling effect 0.5-5 times that of AgGaS2 and a laser damage threshold 1-50 times that of AgGaS2, demonstrating significantly improved performance and making it a potential infrared nonlinear optical material.

The invention provides a rare earth borate second-order nonlinear optical crystal and a preparation method and application thereof, and belongs to the technical field of optical crystal materials. The compound is prepared by a solid-phase synthesis method and a fluxing agent method, and the preparation method comprises the step of growing the rare earth borate nonlinear optical crystal by adopting the fluxing agent method. The obtained product has a large frequency-doubled effect, a large optical band gap, a short ultraviolet cut-off edge and stable physical and chemical properties, and can be used for preparing an ultraviolet nonlinear optical frequency conversion device.

This invention discloses a ruthenium-doped chromium phosphide material, its preparation method, and its applications, belonging to the field of sensor material application technology. The chemical formula of this material is Cr. 1‑x Ru x P, where 0.2

The invention provides a group IIIA nitride single crystal growth method capable of improving crystal quality. A method for growing a GaN single crystal on a GaN substrate (seed substrate (9)) is provided with a thick film formation step for forming a thick GaN single crystal on the GaN substrate (seed substrate (9)) by repeatedly immersing the GaN substrate (seed substrate (9)) in a mixed melt (101) of Ga and Na stored in a crucible (100), lifting the GaN substrate (seed substrate (9)), and then heating the GaN substrate (seed substrate (9)) in a nitrogen atmosphere. The crucible (100) is an alumina crucible containing alumina as a main component and containing an alkali metal other than Na or an alkaline earth metal.

The invention provides a preparation method of a rare earth ion doped yttrium ferrite single crystal. The preparation method comprises the following steps: weighing Re2O3, Fe2O3 and Y2O3 according to the stoichiometric ratio of each element shown in the chemical formula; wherein Fe2O3 is excessive by 5-8% so as to compensate defects caused by volatilization of iron ions; nb2O5 is doped to compensate radius mismatch caused by doping of rare earth ions, and the doping range of Nb2O5 is 1-5% of the content of Re2O3. Then mixing a fluxing agent KCl-LiCl-B2O3 according to a molar ratio of (35 to 42): (35 to 42): (16 to 30) to form a mixed raw material; putting the mixed raw material into a platinum crucible, and heating the inside of the platinum crucible to 1170-1200 DEG C; carrying out heat preservation on the interior of the platinum crucible; cooling the inside of the platinum crucible to 1050-1100 DEG C, and inserting the seed crystal into the platinum crucible; continuously cooling, and rotating the seed crystal; cooling the inside of the platinum crucible to 900-950 DEG C, and finishing crystal growth; and lifting the crystal away from the liquid surface for cooling and annealing to obtain the rare earth ion doped yttrium ferrite single crystal. According to the invention, doping uniformity control, centimeter-level crystal growth, impurity blocking and lattice stress elimination are realized.

The invention discloses a cosolvent for beta-Ga2O3 crystal growth, application of the cosolvent and a crystal growth method, the cosolvent for beta-Ga2O3 crystal growth comprises a mixture composed of bismuth oxide and boron oxide, and the molar ratio range of bismuth oxide to boron oxide is (0.5-2): (2-5). When the cosolvent is used for crystal growth of beta-Ga2O3, the melting temperature can be reduced to 1200 DEG C or below, and the purpose of low carbon is achieved; melting can be carried out in an air atmosphere; the method can be suitable for a relatively high heating rate of 50 DEG C / h to 200 DEG C / h, a relatively short heat preservation time of 3 h to 8 h and a relatively high cooling rate of 5 DEG C / h to 10 DEG C / h, so that the purposes of high efficiency and stability are achieved; and moreover, the cosolvent does not contain toxic auxiliaries such as lead oxide or fluoride, so that the influence on the health of an operator and the environment can be avoided.

This invention relates to a series of alkali metal rare earth chalcogenides and a series of alkali metal rare earth chalcogenide nonlinear optical crystals, their preparation methods, and their applications. The general chemical formula for both the series of halides and the nonlinear optical crystals is A3Ln. 11 Ga 19 Q 45 X3, where A = K, Rb, Cs; Ln = La, Pr, Nd; Q = S, Se; X = Cl, Br, I, all belong to the hexagonal crystal system with space group and cell parameter Z = 1. This series of halides is synthesized using a high-temperature solid-state method, while this series of nonlinear optical crystals is grown using a high-temperature solution method or the Bridgman process. This material can be used to manufacture second harmonic generators, up- and down-frequency converters, optical parametric oscillators, etc.