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

The invention discloses a synthesis method for a La<x>Sr<1-x>Ti<1-y>Mn<y>O<3> (x=0.1-0.6, and y=0.1-0.6) material for a solid oxide fuel cell. N,N-dimethylformamide (DMF) is adopted as a solvent, tetrabutyl titanate is adopted as a titanium source and manganese acetate is taken as a manganese source, so that the process is simple, the prepared powder is uniform in particle size distribution and the particle sizes are smaller than 50nm. The powder prepared through the method is suitable for laboratory synthesis and industrial production of a positive electrode material for the solid oxide fuelcell and a connector 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 wide application prospect in the aspects of manufacturing emerging spin valve devices, magnetoelectric storages, magnetoelectric sensors and microwave resonance devices.

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 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 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 provides a preparation method of graphene-coated nano dysprosium oxide. The method comprises the following steps that dysprosium oxide nanoparticles are prepared through a pyrolysis method; 2, dysprosium oxide nanometer columns are prepared through a hydrothermal method; 3, a graphene oxide solution is prepared; 4, the dysprosium oxide nanoparticles and the dysprosium oxide nanometer columns are added into the graphene oxide solution, stirring and filtering are conducted in sequence, filter residues are obtained, and the filter residues are subjected to heat treatment to obtain graphene-coated nano dysprosium oxide. In addition, the invention provides application of graphene-coated nano dysprosium oxide prepared through the method in the process of preparing two-element-doped magnesium diboride superconducting bulk materials. According to the preparation method, the technological method is simple, graphene with high surface area is adopted as a coating, the dysprosium oxide nanoparticles and the dysprosium oxide nanometer columns can be uniformly dispersed on the graphene without generating agglomeration, and the critical current density Jc performance of the two-element-doped magnesium diboride superconducting bulk materials in a low field and a high field can be improved conveniently.