31results about How to "Reduce phase temperature" patented technology

A preparation method for a strontium titanate lanthanum based powder material belongs to the field of fuel cells. The method adopts a citric acid-nitrate spontaneous combustion method, using citric acid as a complexing agent and a reducing agent, using nitric acid as an oxidizing agent, introducing a sintering acid ammonium nitrate in-situ, dissolving with metal nitrate in deionized water, adding a tetrabutyl titanate citric acid solution to form an even transparent solution, heating in water bath, removing surplus water, forming even sol, and heating the sol in a muffle furnace till spontaneous combustion happens to form fluffy precursor powder. Then Grinding and calcining in an electric furnace to obtain single strontium lanthanum based anode powder. The preparation method has the advantages of being simple in synthesis process, low in cost, fine and even in powder particles and low in material phase forming temperature. The method is also applicable to synthesis preparation of strontium titanate based nanometer powder and can be used for laboratory synthesis and industrial production of a solid oxide fuel cell anode powder material.

The invention belongs to the technical field of information functional materials and in particular relates to BiFeO3-Bi0.5Na0.5TiO3 base multiferroic solid solution ceramic and a preparation method thereof. The preparation method comprises the following steps of: dissolving bismuth nitrate and ferric nitrate in a citric acid solution to form a transparent BiFeO3 solution; dissolving butyl titanate, bismuth nitrate and sodium nitrate into the citric acid solution to form a transparent Bi0.5Na0.5TiO3 solution; mixing the BiFeO3 solution and the Bi0.5Na0.5TiO3 solution by a certain molar ratio and then regulating the pH value to 7-7.5 with ammonia water; aging, dewatering and drying the mixed solution to form black xerogel; grinding the xerogel and carrying out heat treatment to remove organic matters to obtain precursor powder; and grinding, tabletting and sintering the precursor powder to obtain the BiFeO3-Bi0.5Na0.5TiO3 base multiferric solid solution ceramic. The BiFeO3-Bi0.5Na0.5TiO3 base multiferric solid solution ceramic has the characteristics of single phase structure, low leakage current, ferroelectric/ferromagnetic coexistence at room temperature, and the like and has wideapplication prospect in the aspects of manufacturing emerging spin valve devices, magnetoelectric storages, magnetoelectric sensors and microwave resonance devices.

The invention discloses a preparation method of mesoporous hollow sphere-shaped tungsten carbide. The preparation method comprises the following steps: (1) preparing 30%-70% ammonium metatungstate solution at room temperature; (2) fixing a glass container with absolute ethanol in an ultrasonic apparatus, adding the ammonium metatungstate solution obtained in the step (1) at the speed of 1-5 mu l/drop at an interval of 2-8 seconds per drop in the absolute ethanol in the presence of ultrasonic, immediately pelleting and then generating precipitate, dispersing the precipitate by continuous ultrasonic action, and then obtaining ammonium metatungstate particles by filtration and vacuum drying; and (3) carbonizing the obtained metatungstate particles at the atmosphere of CO/H2, and then obtaining the mesoporous hollow sphere-shaped tungsten carbide. The preparation method is simple to operate, the used solvent is clean and environment-friendly, and the prepared metatungstate particles consist of nano tungsten carbide particles.

The invention discloses a preparation method of a high-current-carrying multi-core Bi-2223 superconducting tape under a magnetic field. The method comprises the following steps: 1, adding Bi-2223 precursor powder and CaCuO2 power into a silver sleeve so as to obtain a first tube loading composite; 2, drawing and assembling the first tube loading composite so as to obtain a second tube loading composite; 3, drawing the second tube loading composite into a multi-core Bi-2223 tape; 4, preserving the heat of the multi-core Bi-2223 tape so as to obtain the pretreated multi-core Bi-2223 tape; and 5,thermally treating the pretreated multi-core Bi-2223 tape so as to obtain a multi-core Bi-2223 superconducting tape. The powder tube loading process improves the Bi-2223 grain orientation and grain boundary quality and improves the grain orientation and bonding properties so that the current carrying capacity of the Bi-2223 superconducting tape under the magnetic field can be enhanced and the application in magnets and other fields can be facilitated.

The invention discloses a preparation method of hexaaluminate catalysts AAl12-xBxO19-delta with high specific surface areas. The preparation method comprises the following steps: (1) weighing nitratescorresponding to elements A, B and Al according to a stoichiometric ratio, dissolving the weighed nitrates into deionized water to prepare corresponding nitrate mixed solutions; (2) adding a certainamount of saccharides into the nitrate mixed solutions prepared in the step (1), heating, and stirring to form sols; then, drying the sols to obtain precursors; (3) heating the precursors, obtained inthe step (2), up to 800-1500 DEG C in an inert atmosphere, and roasting; then, calcining in an oxidizing atmosphere, cooling and then crushing to obtain the hexaaluminate catalysts with high specificsurface areas. According to the preparation method, a carbon coating layer, formed by roasting in the inert atmosphere, is used for preventing excessive growth and aggregation of the crystal grains,a carbon layer is removed by calcining in an air atmosphere, and the hexaaluminate catalysts with pure phase structures are further formed; the prepared catalysts have the advantages of being high inspecific surface areas, small in grain sizes and high in methane combustion catalysis activity.

The invention provides a novel garnet-based high efficiency green phosphor, a chemical formula is [(Gd1-xLux)1-yTby]Al5O12 (short for (Gd, Lu)AG:Tb<3+>), wherein x is Lu/(Gd+Lu+Tb) and y is Tb/(Gd+Lu+Tb)(x is 0-1.0, y is 0-0.15). The phosphor takes rare earth nitrate and an ammonium aluminium sulfate according to stoichiometric ratio to prepare a mother salting liquid, the mother salting liquid is dropped into a NH4HCO3 precipitating agent solution, the obtained deposition is centrifuged, washed, and dried to obtain the white precursor powder, and phosphor (Gd, Lu)AG:Tb<3+> can be obtained through calcining at different temperature. non radiation energy transmission of Gd<3+> to Tb<3+> is existed, the fluorescence quantum efficiency is high, addition of Lu can obvious improve the stability of a system, and is more suitable for a scintillator material.

The invention discloses a preparation method of a nanosilver-doped yttrium barium copper oxide film, which comprises the following steps: 1. preparing a nanosilver sol by electrochemical reaction, adding the nanosilver sol into a yttrium barium copper oxide precursor liquid to prepare a precursor sol; 2. evenly applying the precursor sol on a CeO2/YSZ/Y2O3/NiW substrate to obtain a wet film; 3. carrying out low-temperature pyrolysis to obtain a precursor film; 4. crystallizing to obtain the nanosilver-doped yttrium barium copper oxide film. The electrochemical reaction for preparing nanosilver particles does not need dispersant, reducer or other complex compounds, and can easily obtain the high-purity impurity-free nanosilver sol; the nanosilver particles in the prepared precursor sol aredistributed uniformly, do not aggregate, and have high stability, and the dimension of the nanosilver particles is smaller than 20 nm; the nanosilver-doped yttrium barium copper oxide film obtained by applying the precursor sol has the advantages of low phase formation temperature and uniform nucleation, and has a superconductive layer which is 400-600nm thick and has excellent superconductivity.

The invention discloses a method for preparing a double mesoporous high (100) crystal plane tungsten carbide material. The method comprises the following steps of: (1) preparing a mixed aqueous solution of ammonium meta-tungstate and copper sulfate, adding a 5 to 50 mass percent ammonium carbonate aqueous solution dropwise at the speed of 50 to 200mu L/min during ultrasonic oscillation to deposit solid particles, and filtering after a dropwise adding process to obtain precursor particles; (2) drying the precursor particles in vacuum at the temperature of between 60 and 100 DEG C, putting the precursor particles into a tube furnace and carbonizing to obtain a mesoporous tungsten carbide composite material; and (3) performing acid treatment on the mesoporous tungsten carbide composite material, and thus obtaining the double mesoporous tungsten carbide material. Double mesoporous tungsten carbide (WC) which is prepared by the method is formed by piling up nano WC particles, and the growth of a WC (100) crystal plane is promoted, so that the sorption/desorption capacity of the WC to hydrogen (H2) and the electro-catalysis property of the WC are improved.

The invention provides a light emitting diode (LED) capable of emitting white light, relates to the technical field of fluorescence conversion, and solves the problems of low luminous efficiency, poor performance and high cost of an existing LED capable of emitting white light. The LED comprises a blue InGaN chip, yellow light fluorescence powder and packaging materials, wherein the yellow light fluorescence powder and packaging materials are uniformly mixed at the proportion of 0-50 percent by weight, and are coated on the blue InGaN chip to manufacture the LED capable of emitting white light after encapsulating and curing; and the chemical formula of the yellow light fluorescence powder is Ca1-a-x-y MaO : Ce<3+>xR<+>y, wherein a, x and y are molar fraction of elements, and the value range is that the a is smaller than or equal to 0.1 and larger than 0, the x is equal to the y, the x or the y is smaller than or equal to 0.05 and larger than 0, M represents Be<2+>, Mg<2+>, Sr<2+>, Ba<2+>, and Zn<2+> or Cd<2+>, and R represents Li, Na, K, Rb, Cs, and Ag or Cu. The LED provided by the invention has excellent luminescent performance.

The invention discloses a preparation method of conductive metal doped metallic oxide nano particles, belonging to the technical field of nano particle preparation. The method comprises the following steps: (1) preparing a complexing agent solution; (2) acidifying; (3) adding with a metallic oxide raw material; (4) regulating pH value; (5) adding conductive metal soluble salt; (6) baking; and (7) decarbonizing. According to the method, appropriate amounts of concentrated nitric acid and ammonium hydroxide are added to well control hydrolysis of the metallic oxide raw material in solution, and the complexing property of the complexing agent to metal ions is utilized to perform complexation on conductive metal in conductive metal soluble salt, and the reaction is carried out slowly at high temperature, and therefore, the conductive metal doped metallic oxide nano particles are prepared; the method has the advantage of simplicity and convenience in operation, and the prepared nano particles have the characteristics of small particle size, good uniformity and good doping effect.

The invention discloses a nonmetal-ion-doped lanthanum tungstate type mixed proton-electron conductor hydrogen permeation material, and a preparation method and an application of same. The chemical general formula of the material is LnW<1-x>M<x>O<12-delta>, wherein Ln is one of the following lanthanides including La, Nd, Eu and Er, M is one of nonmetal elements P and S and the delta refers to non-stoichiometry, 0 <= delta <= 1, 5.3 <= a <= 5.7 and 0 <= x <= 0.5. The material can be prepared through a glycine-nitrate combustion process. The electronic conductivity of the material is enhancedby doping the nonmetal ions, and further the hydrogen permeation capacity is increased. The material, in a hydrogen-containing atmosphere, has excellent operation stability and can be used for separating hydrogen from a hydrogen-containing gas mixture.

The invention discloses a method for synthesizing electrolyte powder of a solid oxide fuel cell based on a complexing freeze-drying method and the obtained electrolyte powder, and belongs to the fieldof electrolyte synthesis. According to the synthesis method, when the fluorite structure cerium oxide-based electrolyte powder conducted by oxygen ions is synthesized, citric acid and glycine are used as complexing agents, and the complexing capacity, the ignition point and the combustion heat of the two complexing agents are different; the total metal ion concentration and the heat release process during heat treatment can be controlled by adjusting the proportion and the total amount of the double complexing agents, stirring is performed at the temperature of 60-90 DEG C to obtain a metal ion complex solution, then freezing and freeze drying are performed to obtain a dry framework of a metal ion complex, heat treatment is performed to obtain pure-phase cerium oxide-based electrolyte powder, and due to the fact that glycine is added and can serve as a combustion agent, combustion can occur after the heating temperature exceeds the ignition point, and the phase forming temperature isreduced; and according to the synthesis method, the pH value of the solution does not need to be adjusted in the synthesis process, the phase forming temperature of the powder is greatly reduced, andthe improvement of the sintering activity of the powder is facilitated.