104results about How to "Avoid hard clumping" patented technology

A wet chemical process for preparing iron lithium phosphate includes mixing the solution or suspensions of Li source compound, Fe source compound, P source compound, doping element compound or electric conducting agent, and precipitant, reaction at 5-120 deg.C for 0.5-24 hr while stirring, filtering, washing, baking to obtain nano precursor, quickly heating to 500-800 deg.C in non-air or non-oxidizing atmosphere, calcining for 5-48 hr, and cooling. Its advantages are easy control, high uniformity and electric conductivity.

The invention relates to a method for preparing nano hydroxyapatite powder, belonging to the field of the biomedical material. The method for preparing the nano hydroxyapatite powder comprises the following steps: adding the organic polymer of polyethylene glycol to the initial reactants of calcium nitrate and diammonium phosphate solution to adjust and control the morphologies of the products of reaction; adding aqueous ammonia to adjust the pH values of the products of reaction, and making the aqueous ammonia react with the products of reaction at different water bath temperature to synthesize nano hydroxyapatite precipitate, wherein the agglomeration of the synthesized nano hydroxyapatite precipitate can be inhibited by the polyethylene glycol functioning as the dispersant; freezing and drying synthesized nano hydroxyapatite precipitate slurry to obtain dry nano hydroxyapatite powder which contains by-products of reaction and polyethylene glycol, and calcinating the dry nano hydroxyapatite powder at high temperature to remove the by-products of reaction and the polyethylene glycol which are contained in the dry nano hydroxyapatite powder to obtain the nano hydroxyapatite powder which is in the shape of the ball or the rod and in the particle size of 10-100 nm and has high yield and good dispersion. The method for preparing the nano hydroxyapatite powder is simple, needs short preparing period, causes no poison and pollution and is suitable for industrial production.

The invention relates to yttria-stabilized zirconia powder and a preparation method thereof. The yttria-stabilized zirconia powder has the composition characteristics that yttria is taken as a stabilizer of a zirconia material; the powder comprises a doping system formed by one or more following third components: alumina, ceria, lanthana, copper oxide, magnesium oxide and calcium oxide, wherein the weight of the yttria is 2-8mol%, and the total doping weight of the alumina, the ceria, the lanthana, the copper oxide, the magnesium oxide and the calcium oxide is 0-5wt%. According to the yttria-stabilized zirconia powder and the preparation method, the deficiencies of an existing liquid phase preparation process of nanometer zirconia powder are overcome, and the prepared nanometer ZrO2 composite powder has the performance of uniformity in dispersion of components, uniform grain size, super-fineness, high sintering activity, good liquidity and the like. Furthermore, the preparation method is simple in process and low in cost and is easy to industrialize.

A process for preparing nano-class metal particles by dual-pouring method features that under the existance of protector and regulator, the metallic salt is reduced by reducing agent to obtain one ormore (30-100 nm) metallic particles. Its advantages are high dispersity, easy control of diameter, high output rate up to 95%, and preparing the particles of more metals by a single equipment.

The invention discloses a method for preparing a nano-size catalyst of copper chromite and copper ferrite, and belongs to the technical field of nano-size catalyst preparation. The method of the invention comprises a sol-gel process and a vacuum freezing drying (VFD) process. Firstly, a mixed solution is prepared from a soluble copper salt and a soluble chromium salt or iron salt, added with a surface active agent, and mixed uniformly, and then the system is added with a precipitating agent to carry out precipitation reaction under the condition that the pH value is between 6.8 and 9.5, then is kept stand, aged, washed and melted in a water bath for 2 to 8 hours at a temperature of between 70 and 95 DEG C, thus sol is obtained; then the sol is subjected to freezing drying in a vacuum freezing dryer to obtain dried gel which is a precursor of the catalyst; finally, the dried gel is roasted to obtain the nano-size catalyst of copper chromite (CuCr2O4) or copper ferrite (CuFe2O4). The catalyst prepared by the method has the advantages of high purity, small grain diameter, good dispersivity, high catalytic activity, and the like.

The invention provides a tungsten-containing metal oxide nanoparticle dispersoid and a preparation method thereof. The preparation method comprises providing slurry comprising a solvent and tungsten-containing metal oxide nanoparticles dispersed in the solvent, adding a surface modifier to the slurry, carrying out a reaction process until the reaction is finished, separating the tungsten-containing metal oxide nanoparticles subjected to surface treatment in the slurry, and re-dispersing the tungsten-containing metal oxide nanoparticles in the preset solvent so that the tungsten-containing metal oxide nanoparticle dispersoid is obtained. The method for forming the dispersoid through a wet surface treatment method is free of nanoparticle drying and can directly modify the particle surface in the liquid phase so that hard aggregation of the particles is avoided, is simple and easy in operation and can be easily industrialized. The dispersoid obtained by the preparation method has high solid content, a high degree of dispersion, narrow secondary particle size distribution and average secondary particle diameter of 30 to 100 nm.

The invention relates to a material used for a denture, and in particular relates to a ceramic material powder used for denture preparation. The ceramic material powder comprises 90%-95% of stable tetragonal zirconia, and 2.5-3.49% of yttrium oxide used as a stabilizer, wherein a precursor is obtained by coprecipitation reaction of the ceramic material powder; the precursor is sequentially subjected to hydrothermal reaction and spray drying to obtain powder with bending strength greater than 600MPa. A method for preparing the powder comprises the following steps: a, forming 90%-95% of tetragonal zirconia, and 2.5-3.49% of yttrium oxide used as the stabilizer; b, carrying out hydrothermal reaction on the precursor produced in the step a, wherein the reaction temperature is 120-250 DEG C and the reaction time in a high-pressure reactor is 24-48 hours; c, adding a 2-5% polyvinyl alcohol solution into a product obtained in b as adhesive; d, carrying out centrifugal spray granulation on a product obtained in c at hot air temperature of 200-350 DEG C. Through the steps, high-quality ceramic powder with high bending strength greater than 600MPa, high fracture toughness, good chemical stability and good biocompatibility can be obtained.

The invention discloses a preparation method of styrene-acrylic emulsion waterborne antirust paint based on composite modification of polydopamine/nano titanium oxide. The preparation method comprises the following steps: first preparing nano titanium oxide by adopting a sol-gel method, adding a polydopamine solution into a nano titanium oxide stock solution, preparing polydopamine-coated nano titanium oxide under a weak base condition, so that the agglomeration of the nano titanium oxide in the drying process is avoided; and preparing a styrene-acrylic emulsion by adopting a traditional core-shell process, adding phosphate ester monomers and polydopamine-coated nano titanium oxide into a shell-layer monomer, wherein the prepared modified styrene-acrylic emulsion is good in performance. The prepared paint is good in film properties, high in adhesive force, excellent in antirust properties and good in mechanical properties.

The invention relates to a method for preparing hematite-type nano iron oxide red. The method comprises the following steps of: taking ferrous salts as raw materials, adding a dispersant and soluble alkaline matter and controlling pH value to obtain seed crystal; then, adding an oxidant and controlling the pH value by the soluble alkaline matter to carry out reaction at a certain temperature for 0.5 to 1 hour; obtaining solid after sedimentation and filtration of reaction products and carrying out low-temperature vacuum drying on the solid for 0.5 to 2 hours to obtain precursor; and mixing the precursor and a pore-expanding agent to carry out high-temperature ignition for 1 to 2 hours to obtain powder hematite-type nano iron oxide red after cooling and grinding. The preparation method has the characteristics of simple operation, easily obtained raw materials, less pollution, short production cycle, small grain diameter of products, excellent dispersive property, and the like.

The invention provides a cerium/aluminum-based composite oxide with high specific surface area and its preparation method. The composite oxide has chemical formula of AlzCexRyO2, wherein R is rare earth element, x (10-50%), y (1-8%) and z (1-x-y) are molar ratios of Al, Ce and R. The composite oxide is used in three-way catalyst for exhaust gas purification of automobile, has large specific surface area, high thermal stability, and strong oxygen storage ability.

The invention relates to a preparation technology of nano composite material, in particular to a method for simply and rapidly preparing nano WC-Co composite powder. The method comprises the following steps: firstly, preparing solution, secondly, preparing WC-Co composite powder precursor, and thirdly, preparing the nano WC-Co composite powder. The method has the advantages that molecular uniform mixing can be achieved, the prepared WC-Co composite powder has good dispersibility, production equipment and a process route are simplified, reducing gas or inert protective gas with potential hazards, such as H2, CH4, CO and the like, is not required to be used, and the cost is reduced.

A simple and efficient preparation method of nano calcium phosphate comprises steps as follows: A, a calcium salt solution and a phosphate solution are prepared; B, diphosphonate is dissolved in the calcium salt solution, the phosphate solution is dropwise added to the calcium salt solution at the temperature of 37 DEG C, a reaction system is formed, and the pH value of the reaction system is adjusted to 7.0-11.0; the mole ratio of calcium to diphosphonate to phosphorus in the reaction system is (0.50-1.67): (0.01-0.02):1; after titration is completed, the reaction system is continuously stirred for 1-120 min, and the pH value of the reaction system is adjusted to 7.0-11.0; centrifugal washing and filtration are performed, precipitates are re-suspended in absolute ethyl alcohol, and a turbid liquid is obtained; C, a diphosphonate chemical is added to the turbid liquid, nano calcium phosphate slurry is obtained, and the mole ratio of diphosphonate to phosphorus in the nano calcium phosphate slurry is (0.01-0.02):1; the nano calcium phosphate slurry is subjected to ball milling treatment at the rotating speed of 300-600 r/min for 4-12 h and finally dried, and nano calcium phosphate powder is obtained.

The present invention features that two kinds of oxide, including ytterbium oxide and yttrium oxide, are used as the stabilizers simultaneously to coat nanometer zirconia powder and the obtained powder is sintered in the air and without pressure to obtain tetragonal zirconia polycrystal (TZP) and fully stabilized zirconia ceramic (FSZ) with low stabilizer content. The material includes Yb2O3, Y2O3 and monoclinic zirconia powder in purity over 99.9 wt%. The produced TZP ceramic contains Yb2O3 in 1.0-2.0 mol% and Y2O3 in 1.0-2.0 mol%, and the produced FSZ ceramic contains Yb2O3 in 3.0-4.0 mol% and Y2O3 in 1.0-2.0 mol%.

A preparation method of indium tin oxide nano-powder with controllable crystalline form is characterized in that the technological method comprises the following steps: (1) dissolving indium oxide and tin oxide in distilled water, using strong base aqueous solution as precipitant to prepare ITO precursor through two-step precipitation method; (2) washing the sedimentary precursor power with water, drying, grinding, screening to obtain indium tin oxide precursor power; and (3) calcining indium tin oxide precursor power under a certain atmosphere to prepare yellowgreen ITO nano-powder. The invention has the advantages that 1. no hard agglomeration exists among the ITO grains, the grain size is more uniform; 2. the calcining atmosphere can be selected to control the appearance of the ITO grains; 3. the preparation process of the precursor does not use any dispersant or surface complexing agent to inhibit the power agglomeration; and 4. the temperature and precipitation rate can be adjusted to change the grain size and length-diameter ratio of grains during the two-step precipitation process.

The invention relates to a method and a device for preparing nanometer oxide powders without agglomeration. The method combines an electron spraying and a combustion method, separates nanometer particles by charging the surfaces of aerosol particles which are generated during nanometer combustion with the same charge, and overcomes hard agglomeration existing in the combustion method. The preparation device comprises a combustor, a liquid pump, a bracket and a collecting board; an outlet of the liquid pump is connected with an electronic sprayer through a tube; a nozzle of the electronic sprayer aims at an inlet of the combustor, and an outlet of the combustor aims at the collecting board. The method and device of the invention can prepare and obtain the nanometer oxide powders without hard agglomeration.

The invention relates to a nanometer functional powder and the technical field of the preparation method thereof, in particular to a UV resistance and antibiosis nanometer functional powder and a preparation method thereof. The nanometer functional powder consists of the components according to parts by mass as follows: 50 to 70 percent of zinc oxide, 30 to 48 percent of titanium oxide and 0.45 to 2 percent of silver. The preparation method is as follows: zinc hydroxide sol, rutile phase high-pure titanium oxide of 10 to 30 nanometers and silver oxalate are added into a high pressure reaction kettle; the reaction concentration is regulated to be between 8 and 15 percent; the pH is regulated to be between 6.5 and 7.5; then the mixture is reacted for 4 hours under high temperature between 126 and 136 DEG C, filtered, washed and dried under lower temperature between 60 and 70 DEG C, thus obtaining the silver-loaded compound powder of nanometer zinc oxide and nanometer titanium oxide with the UV resistance and antibiosis functions; and the prepared powder has excellent functional cooperation effects and can avoid the fluctuation phenomenon of each function.

The chiral spiral carbon fiber assumes take a hard nanometer pellet as the center highly symmetrically grows, carbon fiber particle size approximately for hard pellet diameter. Its preparation method is take the hard oxide compound as the catalyst forerunner, this oxide compound take the ferric chloride or the ferrous sulfate as the raw material, the citric acid is the complexing agent, the absolute ethyl alcohol forms the even non- hydrosol preparation method for the solvent, after the process complexing dryly forms in the air does the gelatin, in the air bakes in advance removes the organic matter to obtain. 450 deg c under returns to original state in the H2 atmosphere namely obtains a Fe nanometer beaded catalyst. The preparation craft simple, the process is easy to control, is suitable the large scale production. The carbon fiber particle size approximately for the hard nanometer pellet diameter, take iron catalyst becomes as the center of symmetry highly symmetrically grows. We law prepares the carbon fiber is highly symmetrical, on each catalyst granule grows two carbon fibers, is a left hand, is a right hand, also the textile fiber diameter, the curl diameter, the curl turn, the growth direction is all same.

The invention discloses a method for synthesizing nanometer gama-Al2O3 by adopting a solvent replacement/azeotropic distillation drying method. The method is characterized in that the concentration of a AlCl3 solution is 0.7mol.L<-1>, the molar concentration ratio of Al<3+> to a dispersing agent is 250:1, adding a solvent is added and then agitating is carried out, the furnace temperature is 580DEG C, low-cost AlCl3 and n-butyl alcohol replace expensive alcohol aluminum as raw materials, the hydrolysis rate of Al<3+> and the particle size are controlled through adding a surfactant, the hard agglomerate of a precursor aluminium hydroxide gel can be effectively eliminated by adopting the solvent replacement/azeotropic distillation drying method, the prepared nanometer gama-Al2O3 is high in specific area and even in particle distribution, and the particle sizes range from 30nm to 70nm. The prepared nanometer gama-Al2O3 is added in polymeric aluminium chloride and fully mixed to prepare the nanometer modified polymeric aluminium chloride. The waste water coagulating sedimentation effect of the polymeric aluminium chloride can be effectively promoted.

The invention relates to a material for denture, and in particular relates to a zirconium-containing ceramic powder for denture preparation and a preparation method of the ceramic powder. The ceramic powder for denture preparation comprises 90-95 percent by weight of stable tetragonal-zircania and 2.5-3.49 percent by weight of yttrium oxide serving as a stabilizer, wherein a precursor is prepared from the ceramic powder by a co-precipitation reaction; the precursor is sequentially subjected to vacuum lyophilisation, high-temperature calcination and ball mill to form powder with bending strength of more than 600MPa. According to the preparation method, high bending strength can be obtained, and the high-quality ceramic powder with bending strength of more than 600MPa, high fracture toughness, high chemical stability and good bioavailability can be obtained.