284results about How to "Improve magnetic properties" patented technology

The present invention relates to an electromagnetic vibrator of variable reluctance type, according to a new principle which provides higher efficiency, smaller dimension, and higher reliability compared to known technology. This has been obtained by that the magnetic signal flux generated by the coil is closed through a bobbin body and one or more yokes, and wherein the bobbin body and the yokes are made of laminated metal sheets having good magnetic properties.

The invention relates to a manufacturing method of sintering permanent magnetism ferrite by dry-pressing molding. The method comprises following working procedures: crushing process, the preparation process of dry pressing the magnetic powder, dry pressing process and sinter process. The organic dispersant added in the crushing process is one or a plurality among polyethylene glycol, calcium stearate and calcium gluconate, and the content of the organic dispersant is 0.1wtpercent-1.5wtpercent; the bond added in the he preparation process of dry pressing the magnetic powder is one or a plurality among PVA, polyethylene glycol, camphor and stearate, and the content of the bond is 0.1wtpercent-1.5wtpercent. 1. The manufacturing method of sintering permanent magnetism ferrite by dry-pressing molding of the invention has the advantages of that the productivity effect is high, the molding mould is simple and the automation molding is easy to be realized; the surface of the molded finished product is lubricous and even, the fettling is not needed, and the workload of the post processing is decreased greatly; 2. The manufacturing method of sintering permanent magnetism ferrite by dry-pressing molding of the invention adopts the unique preparation technique of dry pressing the magnetic powder, and the orientation in the process of magnetic field press is relatively good, and the high Br and high HCJ dry-pressing sintering permanent magnetism ferrite is easy to be gained; 3. The manufacturing method of sintering permanent magnetism ferrite by dry-pressing molding of the invention adopts the pre-sintering material with a better performance of ion substitutional main prescription, and a dry-pressing anisotropic sintering permanent magnetism ferrite with a better magnetism performance can be achieved.

The invention provides a preparation method for a molecular imprinting material and the molecular imprinting material prepared through the preparation method. The preparation method comprises the steps that silicon oxide is coated on the surfaces of magnetic ferroferric oxide nanometer particles, the magnetic ferroferric oxide nanometer particles are modified with gamma-(methacryloyl chloride) amino propyl trimethoxy silane to obtain magnetic ferroferric oxide nanometer particles with propenyl on the surfaces, the magnetic ferroferric oxide nanometer particles with the propenyl on the surfaces serve as carriers, estrogen receptors are simulated, functional monomers are optimized, a surface imprinting technology is adopted, and then the molecular imprinting material which can simultaneously identify seven kinds of environmental endocrine disrupting chemicals is prepared. According to the preparation method, the easy separation of a magnetic nanometer material, the good water solubility of a silicon oxide nanometer material, the specific recognition ability of molecular imprinting polymers and the surface imprinting technology are mutually combined, the preparation technology is simple, the conditions are mild, the prepared molecular imprinting material is large in adsorption capacity, fast to respond, high in magnetism, good in chemical stability and high in repeating utilization rate, and the problems that at present, multiple trace, steroid and phenol environmental endocrine disrupting chemicals are difficult to simultaneously identify, separate and enrich are solved.

A synthetic method of fabricating highly crystalline and monodisperse nanoparticles of metals, multi-metallic alloys, monometallic oxides and multi-metallic oxides without a size selection process are disclosed. A typical synthetic method comprises the steps of, synthesis of a metal surfactant complex from the reaction of a metal precursor and a surfactant, high temperature thermal decomposition of the metal surfactant complex to produce monodisperse metal nanoparticles, and completing the formation of synthesized metal, metal alloy or metal oxide nanoparticles by adding a poor solvent followed by centrifuging. For obtaining highly crystalline monodisperse nanoparticles, additional steps are necessary as described in the invention. The resulting nanoparticles have excellent magnetic property for many applications.

A permanent magnet is provided which has formed a Dy, Tb film on a surface of an iron-boron-rare earth sintered magnet of a predetermined shape, with diffusion thereof into grain boundary phases, having a higher coercive force. The method of manufacturing a permanent magnet includes a film-forming step of evaporating metal evaporating material containing at least one of Dy and Tb and adhering evaporated metal atoms to a surface of the iron-boron-rare earth sintered magnet, and a diffusing step of performing heat treatment to diffuse metal atoms adhered to the surface into grain boundary phases of the sintered magnet. The metal evaporating material contains at least one of Nd and Pr.

A rare earth sintered magnet as an anisotropic sintered body comprising Nd₂Fe₁₄B crystal phase as primary phase and having the composition R¹_aT_bM_cSi_dB_e wherein R¹ is a rare earth element inclusive of Sc and Y, T is Fe and/or Co, H is Al, Cu, Zn, In, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta, or W, “a” to “e” are 12≦a≦17, 0≦c≦10, 0.3≦d≦7, 5≦e≦10, and the balance of b, wherein Dy and/or Tb is diffused into the sintered body from its surface.

A glassy metal alloy consists essentially of the formula FeaCobNicMdBeSifCg, where "M" is at least one member selected from the group consisting of molybdenum, chromium and manganese, "a-g" are in atom percent, "a" ranges from about 19 to about 29, "b" ranges from about 16 to about 42, "c" ranges from about 20 to about 40, "d" ranges from about 0 to about 3, "e" ranges from about 10 to about 20, "f" ranges from about 0 to about 9 and "g" ranges from about 0 to about 3. The alloy can be cast by rapid solidification into ribbon, annealed to enhance magnetic properties, and formed into a marker that is especially suited for use in magneto-mechanically actuated article surveillance systems. Advantageously, the marker is characterized by substantially linear magnetization response to an applied magnetic field in the frequency regime wherein harmonic marker systems operate magnetically. Voltage amplitudes detected for the marker are high, and interference between surveillance systems based on mechanical resonance and harmonic re-radiance is virtually eliminated.

The invention discloses a flexible rare earth bonded magnet with roll anisotropy and a manufacturing method thereof. The magnet comprises the following components in part by mass: 94 to 97 parts of anisotropic rare earth composite permanent magnet powder, 2.8 to 5.5 parts of binder and 0.2 to 0.5 part of processing aid, wherein the anisotropic rare earth composite permanent magnet powder comprises anisotropic ferrite permanent magnet powder, anisotropic samarium-iron-nitrogen permanent magnet powder, anisotropic neodymium-iron-nitrogen permanent magnet powder and neodymium-iron-boron permanent magnet powder with roll anisotropy. The anisotropic rare earth composite permanent magnet powder is subjected to surface treatment by using a surface treatment agent. A permanent magnet product with the thickness of 0.35 to 8mm and the maximum width of 1,000mm can be manufactured by processing the components by a calendering method; the disadvantages of various conventional permanent magnet materials are overcome; and a magnetic material which has a thin wall, large length-diameter ratio, high flexibility and higher magnetic performance can be manufactured under the condition that an oriented magnetic field is not required to be applied.

The invention discloses a method for preparing metal soft magnetic powder core by adopting inorganic insulation adhesive particles. The method includes steps of 1), matching and mixing the metal soft magnetic powder according to particle size of the powder; 2), adding passivant into the magnetic powder matched in the step 1) and for passivating treatment; 3), mixing the inorganic insulation particles with passivated magnetic powder intensively and directly; 4), adding insulating compound 0-0.1 in weight percentage; 5), moulding mixture obtained in the step 4) at 1200-2500MPa, placing blank samples in a protective atmosphere and subjecting the blank samples to thermal insulation at the temperature of 400-800 DEG C for 0.5-3 hours prior to air cooling and spraying to obtain target products. An inorganic adhesive coating process adopted in the method is pollution-free to environment, passivated films are even and clean, the products after annealing are high in tensile strength with no need for solidification, so that production efficiency is improved. Besides, comprehensive performance of the products is good and above the industry standard.

The present invention provides a method of producing a high permeability grain oriented electrical steel having excellent mechanical and magnetic properties. A hot band having a thickness of about 1.5 to about 4.0 mm has a chemistry comprising about 2.5 to about 4.5% silicon, about 0.1 to about 1.2% chromium, about 0.02 to about 0.08% carbon, about 0.01 to about 0.05% aluminum, up to about 0.1% sulfur, up to about 0.14% selenium, about 0.03 to about 0.15% manganese, up to about 0.2% tin, up to about 1% copper, and balance being essentially iron and residual elements, all percentages by weight. The band has a volume resistivity of at least about 45 μΩ-cm, an austenite volume fraction (γ_{1150° C.}) of at least 20% and the strip has an isomorphic layer thickness of at least about 2% of the total thickness on at least one surface of the hot processed band. The band is rapidly cooled after the anneal prior to cold rolling at a rate of at least 30° C./second from 875-950° C. to a temperature below 400° C. The band is cold reduced in one or more stages with a final reduction of at least 80%, annealed, decarburized and coated with an annealing separator on at least one side. A final annealing provides stable secondary grain growth and a permeability measured at 796 A/m of at least 1840.

The invention relates to an NdFeB (neodymium-iron-boron) magnet, in particular to a method for preparing the NdFeB magnet by waste materials, and belongs to the technical field of magnetic materials. The preparing method of the NdFeB magnet comprises the following steps that firstly, NdFeB magnet waste materials are cleaned and are dried through being blown, the NdFeB magnet waste materials are crushed into particles being 10 to 15mm by a crushing machine, rare earth metal is added into the particles, then, hydrogen crushing treatment is carried out to obtain crushed powder, and next, antioxidants are added for airflow grinding to obtain fine powder with the average particle diameter being 3.0 to 4.0 mu. m; next, lubricating agents are added, orientation is carried out under the protection atmosphere of nitrogen gas, in addition, pressing forming is carried out, and finally, NdFeB magnet finished products are obtained through discharging plasma sintering, secondary tempering heat treatment and surface treatment. The method has the advantages that waste materials are used as major raw materials, the simple and feasible preparing method is adopted, the recovery and utilization rate of the waste materials is effectively improved, in addition, Tb, Dy, Nd and Ce are added and compounded in the preparing process, and the obtained NdFeB magnet has better coercive force, residual magnetism and magnetic energy product.

The invention relates to a method for preparing ferroferric oxide nano-piece through a microwave method, which belongs to the field of preparation of nano-material through a wet chemical method. The method comprises the following steps of: preparing a ferric salt solution by using ethylene glycol by using a soluble trivalent ferric salt as a raw material , adding the sodium acetate and a surfactant in the ferric salt solution, evenly stirring, and irradiating by using microwave to generate ferroferric oxide, filtering and washing the product, drying the product at a constant temperature in air to obtain the ferroferric oxide nano-piece material. The ferroferric oxide nano-piece material synthesized by the method has a thickness of 100nm below as well as the length and width of 1-10microns. The invention has the advantages of high purity of the prepared ferroferric oxide nano-piece, simple synthetic line, short period of microwave reaction of only tens of minute and easy control of the whole process, meets the demands of practical production, and has god application prospect in the fields of catalysis, biological medicine, energy and environment and the like.

The invention discloses neodymium iron boron magnetic materials and a preparation method of the neodymium iron boron magnetic materials. The neodymium iron boron magnetic materials comprise, by weight, 27-34.5 % of neodymium (Nd), 4.5-5.75 % of praseodymium (Pr), 0.45-0.575 of gadolinium (Gd), 2-4% of boron (B), 0.08-0.16 % of niobium (Nb), 0.01-0.02 % of hafnium (Hf), 0.01-0.02 % of wolfram (W) and 0.045-0.0575 % of scandium (Sc), and the rest is ferrum (Fe). The neodymium iron boron magnetic materials have uniform textures and strong structures, and can not only improve tenacity performance of the materials but also improve magnetic performance to some extent. The preparation method of the neodymium iron boron magnetic materials fully utilizes praseodymium-neodymium waste materials to directly produce raw materials for alloy, is flexible in composition proportion, qualified in quality control, capable of reducing cost and simple in technology, and fully utilizes waste powder materials with high oxygen content.

A composite nanoparticle as the magnetic core carried photocatalyst is composed of the magnetic Fe3O4 nanoparticle as core, SiO2 coated on the surface of said core, and TiO2 carried by said SiO2/FeO4 particle, and is prepared by chemical codepositing method. A method for using said photocatalyst to clean sewage features that the organic pollutants in sewage is deeply oxidized by it to generate CO2 and H2O. Its photocatalyzing apparatus is composed of high-pressure Hg lamp, quartz sleeve tube, bias electrode, condensing water inlet and outlet, gas distributing plate, said photocatalyst, ring reaction chamber, organic class container, sampling opening and aerating unit.

The invention discloses a preparation method for carbon nano tube surface loaded magnetic alloy nano particle composite material, which belongs to the field of electromagnetic wave absorbing material preparation. The preparation method comprises the following steps: after purifying and activating a carbon nano tube, evenly dispersing the carbon nano tube to chloride salt solution of iron, cobalt and nickel, slowing adding an alkali solution dropwise into the solution in the fierce agitation process, and regulating the pH value of the solution and making iron ions, cobalt ions and nickel ions be coprecipitated onto the surface of the carbon nano pipe in the form of hydroxide according to the alloy proportion set when the solution is prepared; taking out a deposit by centrifugation or filtering; and after drying the deposit, carrying out the heat treatment of the deposit in the reducing atmosphere to obtain the carbon nano tube composite material loaded with magnetic alloy particles. The preparation method adopts a simple process. As no impurity element is introduced into the preparation process, the obtained magnetic alloy particles have high degree of crystallinity and excellent magnetic properties. In addition, the method has easy regulation of the alloy components. The composite material prepared by the method is significantly applied in the fields of electromagnetic interference resistance, stealth, microwave darkrooms, and the like.

The invention discloses a preparation method of nanometer Zn crystal boundary modified sintered NdFeB magnet with high corrosion resistance, comprising the following steps: 1) main-phase alloy and crystal boundary phase alloy are respectively prepared, wherein, the main-phase alloy adopts casting technology or rapid hardening melt-spun technology to prepare a cast ingot or a rapid hardening thin strip, and the crystal boundary phase alloy adopts rapid quenching technology to prepare a rapid quenching strip; 2) the prepared main-phase alloy and crystal boundary phase alloy are respectively prepared into powder; 3) nanometer Zn powder is mixed with the crystal boundary phase alloy powder to evenly disperse the mixture on the crystal boundary phase alloy powder surface; 4) after nanometer Zn modified crystal phase alloy powder is evenly mixed with the main-phase alloy powder, orientation compression in a magnetic field is prepared into a green body; 5) the green body is sintered in a high vacuum sintering furnace and tempered to prepare the final magnet. The sintered NdFeB magnet prepared by the method of the invention has high performance, favourable corrosion resistance, simple technology and simple operation, and is favourable for batch production on large scale.

The present invention has as its object to stably produce a high strength electrical steel sheet and a processed part of the same which is high in strength and has wear resistant and is superior in magnetic flux density and core loss without greatly changing the cold rollability and production processes from those of conventional electrical steel sheet and provides a high strength electrical steel sheet characterized by containing, by mass %, C: 0.06% or less, Si: 0.2 to 6.5%, Mn: 0.05 to 3.0%, P: 0.30% or less, S or Se: 0.040% or less, Al: 2.50% or less, Cu: 0.6 to 8.0%, N: 0.0400% or less, and a balance of Fe and unavoidable impurities and containing in the steel a metal phase composed of Cu of a size of 0.1 μm or less. The method of production of the same comprises holding in a temperature range of 300° C. to 720° C. for 5 seconds or more for heat treatment.

The invention relates to a preparation method of a ZnFe2O4/ Ag3PO4 composite photocatalyst, belonging to the technical field of environmental material preparation. An ion exchange technique is adopted for the invention, and the preparation method comprises the steps of firstly, feeding FeCl3.6H2O solid and ZnCl2 solid into ethylene glycol, evenly stirring, then feeding sodium acetate (NaAC) and polyethylene glycol (PEG) into the mixture, continuously mixing, and carrying out a reaction to obtain ZnFe2O4 nanospheres; after that, feeding the ZnFe2O4 nanospheres into deionized water, rapidly stirring, dropwise adding a disodium hydrogen phosphate solution, carrying out a reaction, then dropwise adding a silver nitrate solution, stirring until reactants have a full reaction, washing the product, and then carrying out vacuum drying on the washed product to obtain the ZnFe2O4/Ag3PO4 composite photocatalyst. A composite visible light photocatalyst system is established; a heterogeneous structure system is established, so that the activity and the stability of silver phosphate can be improved; furthermore, the photocatalyst can be efficiently recovered by using the ZnFe2O4; the composite photocatalyst has a better degrading effect for the antibiotics in waste water.

The invention discloses a preparation method of RGD-modified ultra-small magnetic iron oxide nanoparticles. The preparation method comprises the following steps: preparing ultra-small magnetic iron oxide nanoparticles by taking ferric acetylacetonate as a reaction raw material and a precursor, taking oleylamine as a surfactant and a reducing agent and taking dibenzyl ether as a solvent; replacing oleylamine molecules wrapped on the surfaces of the nanoparticles by utilizing dopamine-modified HOOC-PEG-COOH to realize PEG-modification of the surfaces of the nanoparticles; and finally, chemically coupling RGD cyclic peptide by virtue of free carboxyl at the tail end of the PEG to obtain the RGD-modified ultra-small magnetic iron oxide nanoparticles. The method of synthesizing the ultra-small magnetic iron oxide nanoparticles has the characteristics of a simple process, a high raw material conversion ratio, strong repeatability and the like. The synthesized magnetic iron oxide nanoparticles have the characteristics of a regular morphology, an ultra-small dimension, good stability, good monodispersity, high biocompatibility, and tumor specific targeting, and the like, and can be used as a T1-weighted imaging high-performance magnetic resonance imaging contrast agent with a tumor active targeting function.

The method includes steps: (1) using ingot-casting technique to manufacture Nd-Fe-B ingot-casting alloy, or using technique of rapid hardening sheet to produce rapid hardening sheet of Nd-Fe-B alloy; (2) first carrying out coarse crushing for alloy, then producing powder through airflow grinding; (3) adding powder of boron nitride or magnesia, and mixing them evenly; (4) pressure molding oriented mixed powders under magnetic field, and then carrying out cold isopressing process for blanks; (5) sintering and tempering blanks in high vacuum sintering furnace. Nd-Fe-B magnet produced according to the invention possesses better magnetic performance and corrosion resistance than magnetic performance and corrosion resistance of magnet without adding powder of boron nitride or magnesia.

The present invention relates to an MRI contrast agent that includes zinc-containing water-soluble metal oxide nanoparticles and has an improved contrast effect. The zinc-containing water-soluble metal oxide nanoparticles are characterized by addition of zinc to a matrix comprising the metal oxide nanoparticles or by substitution of metal in the matrix, resulting in the improved contrast effect of MRI. In addition, the zinc-containing metal oxide nanoparticles of the present invention include the MRI contrast agent t having hybrid structures of “zinc-containing metal oxide nanoparticle—biologically/chemically active material” in which the nanoparticle is conjugated with a bioactive material such as proteins, antibodies, and chemical materials.

The invention discloses a rare earth hydride surface coating treating agent, a method for forming a rare earth hydride surface coating and application of the rare earth hydride surface coating treating agent, which are used for improving the coercive force of a sintering NdFeB magnet and belong to the technical field of magnetic materials. The coating treating agent is a colloid solution formed by dispersing rare earth hydride into a methanol or ethanol solvent. The method for forming the rare earth hydride surface coating comprises the following steps of: injecting the treating agent into glassware and soaking a magnet into a solution; carrying out ultrasonic processing on the treating agent containing the magnet so that rare earth hydride in the treating agent is uniformly coated on the surface of the magnet to form a surface coating with even thickness; taking the magnet provided with the rare earth hydride surface coating out of the solution and volatilizing the solvent in the magnet surface coating in an air drying way to form a coating; and placing the air dried magnet into a vacuum heat treatment furnace and carrying out heat treatment for 0.5-2 hours in a temperature range of 500-950 DEG C. The invention can obviously improve the magnetic performance of the magnet, especially the coercive force of the magnet.

The invention provides an inclusion control method of an Si-Mn-killed non-oriented silicon steel, and belongs to the technical field of steel smelting. The non-oriented silicon steel comprises the following chemical components: not greater than 0.005% of C, 0.4-1.0% of Si, 0.20-0.80% of Mn, not greater than 0.04% of P, not greater than 0.005% of S, not greater than 0.005% of Als, and the balance Fe and inevitable impurities. The method comprises the processes of smelting through a converter, refining under RH and vacuum, and continuously casting; the slag amount of the steel from the converteris strictly controlled; lime, synthetic slag and calcium carbide are added to adjust the slag; the refining under HR and vacuum is that a deep decarbonization mode is carried out; after decarbonization, metallic aluminum is added to realize preliminary dexidation, and SiC is added to the ladle slag surface at the same time in order to deoxidize and modify the slag; the operation is circulated for1-3min; then low-carbon low-titanium ferrosilicon is added to realize Low carbon, low titanium ferrosilicon; the operation is circulated for 3-6min, then manganese metal, ferrophosphorus and the likeare added to alloy, and the net circulating time is beyond 8min after alloying. With the adoption of the method, the composition of nonmetal inclusions in the steel can be improved, so that the performances of the non-oriented silicon steel can be improved, and the foundation is supplied to develop high-performance non-oriented silicon steels.

The invention relates to the technical field of a rare earth permanent magnetic material and relates to a magnetic phase composite rare earth permanent magnetic alloy and a preparation method thereof. The permanent magnetic alloy comprises the following chemical components in mass percentage: REaFe99-a-bB1Mb, wherein a is more than or equal to 28, but less than or equal to 32, b is more than 0, but less than or equal to 10, RE comprises at least two selected rare earth elements from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and M is one or more from Co, AL, Cu, Ga, Nb, Mo, Ti, Zr and V. Magnetic phase composite preparation is performed on the permanent magnetic alloy by crushing, mixing, sintering and thermally treating at least two rapid hardening strips with different components, wherein the rapid hardening strips are at least two 2-14-1-type magnetic main phases (RE) 2Fe14B containing different rare earths respectively. Through mutual proportioning of different proportions of rapid hardening strips, a magnet containing designed components is prepared; the magnet comprises two or more 2-14-1-type magnetic phases consisting of different rare earths, including a 2-14-1-type magnetic phase consisting of a single rare earth; and good comprehensive magnetic property is obtained on the premise of reducing the heavy rare earth content.

The invention discloses a supported palladium catalyst Fe3O4/SiO2/Pd for Suzuki reaction, and a preparation method of the supported palladium catalyst Fe3O4/SiO2/Pd. The compound is a supported palladium catalyst material containing Fe3O4/SiO2/Pd, obtained by composite reaction of a precursor-based Fe3O4/SiO2 composite particles and Pd; the supported palladium catalyst Fe3O4/SiO2/Pd has the molecular characteristics that the compound structure contains a magnetic nanometer material Fe3O4 and porous absorption materials SiO2 and Pd; the supported palladium catalyst has relatively good magnetism, is easy to recover and reuse, and is a relatively ideal material as the supported palladium catalyst. The supported palladium catalyst is simple in synthesis route, mild in reaction condition, relatively high in yield and convenient to apply; post-treatment is simple; meanwhile, a secondary resource generated in biological mineral separation preparation and simulation and coal biological desulphurization by adopting thiobacillus ferrooxidans as a raw material; and a reference is provided for a comprehensive utilization technology of developing a metallurgical tail liquid or a desulphurization waste solution.

The invention relates to the technology of rare-earth permanent magnet materials, and particularly discloses a rare-earth permanent magnet with high magnetic performance and high electric resistance and a preparation method thereof. The permanent magnet comprises the following components in part by mass: 100 parts of neodymium iron boron and samarium cobalt type magnetic powder with granularity of 20 to 300 microns, 0.1 to 5 parts of titanate coupling agent, 1 to 10 parts of bisphenol A epoxy resin and 0.2 to 2 parts of bisphenol F epoxy resin; the components are evenly mixed, and then are molded to form a cured substance at the temperature field of between 20 and 200 DEG C under the orientation field of which the magnetic field intensity is 0.5 to 3T; and the preparation method for the rare-earth permanent magnet comprises the following steps: coupling the surface of the magnetic powder and the coupling agent, then mixing the magnetic powder, the coupling agent and the resin, drying and grinding the mixture, and molding the mixture at the temperature field under the orientation field. The magnetic performance of the permanent magnet of the invention can keep higher level and has no obvious decline compared with the magnetic performance of the high-end adhesive NdFeB magnet, and the electric resistance of the magnet is improved by over 10 times; and the permanent magnet has no obvious temperature rise under the high-frequency alternating field for 1 hour.

The invention discloses an organic insulating binder for a metal soft-magnetic composite material and a magnet preparation method thereof. The organic insulating binder is composed of liquid A and liquid B, wherein the liquid A is a 0.2%-0.6% silane coupling agent; the liquid B is an insulated coating liquid which is formed by mixing 10wt%-30wt% of alicyclic epoxy resin, 5wt%-15wt% of methyl hexahydrophthalic anhydride, 20wt%-60wt% of silicon resin and 10wt%-40wt% of dimethyl benzene, wherein total dosage of the liquid B is 0.5%-1.5%. The preparation method comprises the following steps: uniformly coating a layer of liquid A silane coupling agent on the surface of metal powder; then, coating the liquid B coating liquid; and preparing the metal soft-magnetic composite material by the steps such as drying, profiling, degreasing and thermal-treating. Compared with an organic binder with other components, the organic substance insulating binder disclosed by the invention has a high heat-resistant temperature and good binding effect, can reduce dosage, so that content of non-magnetic substances is reduced, thereby facilitating improving magnetic conductivity of a magnet and lowering loss. The metal soft-magnetic composite material prepared by adopting the preparation method disclosed by the invention has better magnetic performance and frequency stability.

A method for preparing a soft magnetic composite material through hot pressing includes the following steps: dispersing particle soft magnetic powder into a dispersing medium, adding a coupling agent to conduct surface processing, conducting separation to obtain magnetic powder wrapping the coupling agent, conducting washing and drying through absolute ethyl alcohol to obtain the coupling agent modified magnetic powder, mixing the epoxy resin and an epoxy hardener to obtain an epoxy resin system mixture, mixing the coupling agent modified magnetic powder and the epoxy resin system mixture according to the proportion to obtain mixed slurry containing the magnetic powder and the epoxy resin system mixture, pouring the mixed slurry into a container, conducting vacuumizing, arranging the container into a constant temperature oven to conduct procuring to obtain composite slurry obtained through procuring, transferring the procured composite slurry into a mould, and conducting solidification and die pressing through a hog pressing machine to obtain the soft magnetic composite material. The method is simple in process, low in cost, favorable for operation and capable of achieving good magnetic performance and dynamic strength of the composite material by adjusting the content of the magnetic powder. The shape is controllable, and the mechanical performance is good.

The invention, belonging to the field of functional materials prepared by using plant nano-fiber composite metal nano-particles, particularly relates to a composite material based on natural plant nano-fibers and metal nano-particles and a preparation method thereof. The preparation method comprises the following steps: putting the natural plant nano-fibers in water to prepare a suspending liquid, then adding a metal precursor for reacting, carrying out centrifugation on a product obtained by the reaction, and carrying out freeze drying to obtain the composite material uniformly loading metal nano-partilces on the surface of the natural plant nano-fibers. According to the invention, the natural plant nano-fibers are used as a reducing agent, a stabilizing agent and a template; the metal precursor is reduced in the aqueous solution; and the metal nano-particles are further reduced through one-step method by using polyhydroxy, phenolic group, carboxyl and other structures of the surface of the natural plant nano-fibers. The method does not use toxic reducing agent, solvent and organic stabilizer, and the synthetic route is simple and green.

An iron nitride magnetic powder comprised primarily of Fe₁₆N₂ phase is characterized in that its coercive force Hc is 200 KA/m or greater and bulk switching field distribution BSDF is 2 or less. The magnetic powder can be produced by allowing a nitriding reaction of Fe particles with a nitrogen-containing gas for producing nitrided particles of primarily Fe₁₆N₂ phase to proceed under an increased pressure of 0.1 MPa or greater. The enhanced properties of the iron nitride magnetic powder make it suitable as a magnetic material for high-density magnetic recording media.