86 results about "Ferrite powder" patented technology

The invention belongs to the field of ferrite materials, and particularly relates to a high-coercivity strontium ferrite with iron partially replaced by aluminum and a preparation method of the high-coercivity strontium ferrite. Aiming at the problem of low coercive force of a ferrite pre-sintering material in the prior art, iron is partially replaced by aluminum, ferric nitrate, strontium nitrate, aluminum nitrate and glucose are used as reaction raw materials, the ratio of the total molar weight of Fe and Al to the molar weight of Sr is (9.5-12): 1, the ratio of the molar weight of Al to the total molar weight of Fe and Al is (0-0.41): 1, and the molar weight of glucose is 0.5-3.5 times of the total molar weight of Fe, Al and Sr; and calcining at 900-1200 DEG C for 1-3 hours by adopting a solution self-combustion-aluminum ion substitution method to prepare the strontium permanent magnetic ferrite powder material with high coercivity.

The invention belongs to the technical field of radio frequency microwave functional components, and particularly relates to a pouring type integrated transformer, an internal matching component and a preparation method thereof, the pouring type integrated transformer comprises a microstrip impedance line of a multilayer spiral structure, a soft magnetic ferrite pouring body located outside the microstrip impedance line, and leading-out terminals arranged at the two ends of the microstrip impedance line; the micro-strip impedance line is arranged on a substrate with a certain dielectric constant requirement and forms a spiral structure along a set path, the micro-strip impedance line and the substrate of the micro-strip impedance line are coated with the soft magnetic ferrite pouring body, the soft magnetic ferrite pouring body is of an integrally formed structure, and the soft magnetic ferrite pouring body is obtained by mixing soft magnetic ferrite powder and a binder, pouring the mixture in a mold and carrying out curing demolding. Through the innovative structural design and preparation process, the technical bottlenecks of large size, low efficiency, inconsistency, difficulty in packaging and the like existing in a traditional manual winding matching mode are overcome, and a feasible technical scheme is provided for miniaturization, high performance and large-scale application of a power amplifier matching network in a radio frequency microwave system.

This invention relates to the technical fields of RFID equipment manufacturing and novel magnetic inks, providing a magnetic ink for RFID electronic tags and its preparation method. The magnetic ink comprises bisphenol A epoxy acrylate prepolymer, modified polyester resin, polyamide-imide resin, nano-scale soft magnetic ferrite powder, silver-coated flake copper powder, low-polymerization-degree polyurethane compatibilizer, γ-glycidyl etheroxypropyltriethoxysilane coupling agent, photoinitiator, antioxidant, leveling agent, and reactive diluent monomer. The ferrite powder has a D50 of 0.1-0.3µm and its surface is treated with a phosphate ester-silane double coating. After UV curing, its magnetic permeability is 20-60, and its loss tangent is ≤0.05. This invention's ink possesses excellent magnetic properties, conductivity, and flexibility, effectively improving the tag's electromagnetic response, crack resistance, and printing accuracy. It is suitable for printing high-Q value narrow-linewidth antenna patterns.

The application belongs to the technical field of magnetic material preparation, and particularly relates to a production process of high-performance rare earth permanent ferrite magnetic powder. The process comprises the following steps: preparing iron red and auxiliary materials, wherein the auxiliary materials comprise calcium carbonate, strontium carbonate, lanthanum oxide and cobalt oxide; mixing raw materials in proportion, then performing dry ball milling to obtain mixed materials; performing steam treatment on the obtained mixed materials to make the water content of the mixed materials reach 2-5%, then performing ripening, and the ripening time is at least 30 min, and the ripening process is completed in the screw conveyor; balling; pre-sintering; performing coarse crushing on the pre-sintered materials and sieving to obtain rare earth permanent ferrite magnetic powder. Through steam pretreatment and ripening, the strength and thermal stability of the ball materials are significantly improved, the ball materials remain complete in the kiln, the flowability is good, and the consistency and qualified rate of the product are improved.

The present invention generally relates to a method for synthesizing dysprosium-doped copper-zinc ferrite nanomaterials with enhanced structural and functional properties. The method comprises dissolving stoichiometric quantities of copper nitrate trihydrate, zinc nitrate hexahydrate, iron nitrate nonahydrate, and dysprosium nitrate hexahydrate in distilled water to prepare an oxidizer solution. A fuel mixture is separately prepared using urea and glucose in equal proportions by weight. The oxidizer and fuel mixtures are combined in 1:1 ratio, calculated based on their respective oxidizing and reducing valencies, to form a homogeneous precursor solution. This solution is stirred thoroughly for about one hour and subsequently transferred to a Pyrex dish. The dish is placed in a muffle furnace preheated to approximately 450° C., where the solution undergoes a self-sustained combustion reaction, yielding a fine, porous Cu0.5Zn0.5DyxFe2-xO4 ferrite powder within 20 minutes. The resultant powder is ground to achieve uniform particle distribution suitable for advanced applications.

The invention discloses a preparation method and application of ferrite-based micron-sized flaky microwave absorbent powder, and relates to the technical field of microwave absorbing materials.The preparation method comprises the following steps that S1, ferrite precursor tape casting slurry A is pretreated, and slurry B is obtained; s2, the slurry B is poured into a casting machine for casting, and a casting green tape C is obtained at an outlet of the casting machine; s3, stripping and removing the PET substrate on the tape casting green tape C to obtain a ferrite green tape sheet D; s4, sintering the ferrite green tape sheet D in sintering equipment, and cooling to room temperature to obtain a ferrite sheet E; and step S5, crushing the ferrite sheet E, and performing classified screening treatment to obtain the flaky ferrite absorbent powder. According to the invention, the design is reasonable, the flaky ferrite powder is used as the magnetic absorbent, compared with the traditional flaky carbonyl iron, the ferrite material has obvious lightweight and anticorrosion advantages, the labyrinth effect formed by the flaky structure can further improve the anticorrosion performance of the product, and impedance mismatching caused by eddy current loss is avoided.

The present invention developed a composite having a novel structure containing, in a high content, a powder having a radiation-shielding function.　Provided is a composite having a radiation-shielding function and a method for producing the same. The composite comprises a preform made from a mixture containing a liquid silica-based binder and one or more radiation-shielding powders selected from gadolinium oxide, boron carbide, boron oxide, boron, barium sulfate, strontium oxide, tungsten, tungsten oxide, tungsten carbide, molybdenum, molybdenum oxide, iron powder, iron oxide powder, and ferrite powder, the radiation-shielding powder(s) being contained in the range from 3% to 85% in total. All of the voids in the preform are impregnated and filled with molten aluminum and solidification is allowed to occur to form a composite, or 25% or more of the voids in the preform are impregnated with a liquid organic / inorganic sealing agent and solidification is allowed to occur to form a composite. The liquid silica-based binder has properties that allow the preform to be formed at a temperature at which the radiation-shielding powder(s) does not decompose.

A multi-pump servo motor driving module for a ferrite powder press comprises a main driver, a first slave driver and a second slave driver, a power supply port of the main driver is connected with a main servo motor, power supply ports of the first slave driver and the second slave driver are respectively connected with a first slave servo motor and a second slave servo motor, and the first slave driver and the second slave driver are respectively connected with the main driver and the second slave driver. The ferrite powder pressing machine has the beneficial effects that firstly, the ferrite powder pressing machine realizes multi-pump linkage operation, part of procedures can be overlapped and carried out at the same time, the waiting time between the forming procedures is reduced, and the forming period is greatly shortened; secondly, the servo motor pump is used for closed-loop control, oil can be reasonably supplied to different hydraulic pumps according to the requirements of all working procedures, and different moments, angles and speeds needed by different working procedures are matched;

The invention discloses a snow melting process based on electromagnetic induction heating of a turnout, which comprises electromagnetic induction coils attached to the waist of a turnout steel rail and the side face of a turnout sliding plate, and electronic paste containing graphene, silver, copper, nickel and ruthenium series resistance paste and a dopant prepared by compounding spinel cordierite and ferrite is burnt and injected to the outer sides of the coils. Alternating current is applied to the coil to generate a magnetic field, the inner side magnetic flux enables the steel rail to generate eddy current heating, the outer side magnetic flux enables slurry carriers to migrate to generate Joule heat, and a synergistic heating infrared radiation system is formed. The method has the beneficial effects that ice and snow on the surface of a turnout steel rail, a rail gap and a sliding plate area are synchronously melted, the technology utilizes the infrared radiation characteristics of graphene, spinel cordierite and ferrite powder, original vacant magnetic flux is utilized, the magnetic flux utilization rate is increased, power consumption is reduced, and the snow melting efficiency and reliability are improved.

The invention relates to a preparation method of a YIG-M type barium ferrite mixed material for a microstrip line circulator. The preparation method comprises the following steps: firstly, preparing YIG precursor powder and barium ferrite powder; pressing the YIG precursor powder into a green body, and sintering to obtain phase-formed YIG ferrite; and crushing the YIG ferrite, mixing the crushed YIG ferrite with the barium ferrite precursor powder according to a mass ratio of 1: 2-2: 1, pressing the mixture into a green body, and carrying out sintering phase formation to obtain the YIG-M type barium ferrite mixed material. The external bias magnetic field of the prepared mixed material is far smaller than that of a traditional YIG material, a good circulation effect can be achieved only through a smaller permanent magnet, and a circulator can be further miniaturized and integrated.

The invention relates to the technical field of transformer manufacturing, in particular to a laminated transformer preparation method and a laminated transformer. The preparation method of the laminated transformer comprises the following steps: respectively preparing ferrite powder and microcrystalline glass ceramic powder into a first green tape and a second green tape by adopting a tape casting process; forming through holes in the first green tape and the second green tape, and filling the through holes with conductive paste; a primary coil layer and a secondary coil layer are printed on the first hole filling green ceramic tape; laminating a plurality of coil hole-filling green ceramic tapes and a plurality of second hole-filling green ceramic tapes according to a preset sequence to form an intermediate electrode layer; laminating a plurality of first green tapes to form a cover layer; stacking the two cap layers and the intermediate electrode layer together to form a block; and sintering the laminated monomers to obtain the laminated transformer. The problems of interface stress concentration and structure cracking caused by difference of thermal expansion coefficients of different materials are effectively solved, and the product yield and reliability are remarkably improved.

Provided are: a ferrite powder whereby, when the ferrite powder is applied in a composite material, dropping out of ferrite particles is suppressed without moldability and filling ability being compromised; a ferrite resin composite material; and an electromagnetic shielding material, an electronic material, or an electronic component. This ferrite powder includes at least spherical or polyhedral ferrite particles in which a step structure is provided on surfaces thereof, the step structure having a polyhedral outline in the surfaces of the ferrite particles.

The application discloses a preparation method of a magnetic high-entropy alloy composite material, and belongs to the technical field of magnetic material preparation. The saturation magnetization intensity of the magnetic high-entropy alloy composite material can reach 153-172 emu / g, the hardness value can reach 200-233 HV, the tensile strength can reach 600-712 MPa, and the coercive force is less than 200 Oe. The preparation steps comprise the following steps: (1) high-entropy alloy powder preparation; (2) ferrite powder preparation; (3) mixing the powders obtained in the steps (1) and (2) with proper additives; (4) loading into a mold and pressure forming; (5) sintering, and the magnetic high-entropy alloy composite material is obtained. The high-entropy alloy magnetic composite material obtained by reasonably controlling the high-entropy alloy composition, the ferrite composition, the proportion of the two components and the sintering process has excellent mechanical properties and outstanding high-frequency magnetic properties.

The invention relates to a method for preparing nano barium ferrite powder, in particular to a method for preparing nano barium ferrite through cooperation of laser annealing and neodymium doping. The method comprises the following steps: S1, preparing a ferrite amorphous strip from raw materials including Fe2O3, BaO, Nd2O3 and B2O3 by utilizing a smelting melt-spinning method; s2, irradiating the ferrite amorphous strip in the step S1 by using laser, and carrying out laser annealing; and S3, carrying out pickling crushing and filtering washing treatment on the annealed strip, and drying to obtain the neodymium-doped nano barium ferrite. According to the preparation method disclosed by the invention, through the synergistic effect of laser annealing and strong absorption of neodymium ions, overgrowth of crystal grains is effectively inhibited, and the particle size distribution of the nano ferrite is narrowed, so that the problems of wide particle size distribution of powder, low production efficiency and the like in the existing preparation technology are solved.

To develop a composite of a new constitution containing a powder having a radiation shielding function in a high content.SOLUTION: Molten aluminum is impregnated and filled into all voids of a preform made of a mixture containing one or more kinds of radiation shielding powders selected from gadolinium oxide, boron carbide, boron oxide, boron, barium sulfate, strontium oxide, tungsten, tungsten oxide, tungsten carbide, molybdenum, molybdenum oxide, iron powder, iron oxide powder, and ferrite powder and a liquid silica-based binder, the mixture containing the radiation shielding powders in a range of 3 to 85% in total; In the composite body having the radiation shielding function and the method for manufacturing the same, a liquid organic-inorganic sealing agent is impregnated and solidified to form the composite body, and a liquid silica-based binder has characteristics capable of forming a preform at a temperature at which the radiation shielding powder is not decomposed.SELECTED DRAWING: None

The present invention provides a ferrite powder which contains 0.9% by mass to 2.5% by mass of lithium (Li), 1.0% by mass to 8.0% by mass of manganese (Mn), and 58.0% by mass to 69.5% by mass of iron (Fe), and has a crystal phase belonging to the space group P4132 and a crystal phase belonging to the space group Fd-3m. In the X-ray diffraction profile, the half width of the (311) plane of the crystal phase belonging to the space group Fd-3m is 0.09° to 0.22°, and the volume average particle diameter D50 is not less than 1 μm but less than 20 μm.

The application provides an amorphous magnetic powder core and a preparation method thereof, and the preparation method comprises the following steps: (1) brittle heat treatment is performed on a Fe-based amorphous alloy, the amorphous alloy is broken and then pre-annealing treatment is performed to obtain amorphous powder, and two portions of the amorphous powder are taken and sieved through different sieves to obtain first powder and second powder; (2) the first powder and the second powder are mixed, and then MgO is used to perform magnetron sputtering treatment on the first powder and the second powder to obtain precursor powder; (3) surface modification treatment is performed on nano ferrite powder, the precursor powder and the surface-modified nano ferrite powder are mixed and ground, a binder is added for granulation, and then annealing treatment is performed after compression treatment to obtain the amorphous magnetic powder core. The amorphous powder / MgO / ferrite double-layer core-shell structure amorphous composite material is prepared by using the magnetron sputtering method and the mechanical ball milling method, and the prepared magnetic powder core has high permeability, low power loss and good direct current superposition performance.

The invention discloses a preparation method of a composite wave-absorbing film and the composite wave-absorbing film. The method comprises the following steps: mixing a strontium source, an iron source and fused salt, and grinding to obtain a first mixture; the first mixture is subjected to high-temperature sintering and then crushed, and first powder is obtained; and washing and drying the first powder, and grinding to obtain the strontium ferrite powder. Mixing the first aramid nanofiber aqueous dispersion with the strontium ferrite aqueous dispersion to obtain a first mixed dispersion; and carrying out vacuum filtration on the first mixed dispersion liquid to obtain the first composite film. Mixing the second aramid nanofiber aqueous dispersion liquid with the Ti3C2Tx aqueous dispersion liquid to obtain a second mixed dispersion liquid; and carrying out vacuum filtration treatment on the second mixed dispersion liquid to obtain a second composite film. The first composite film and the second composite film are stacked and then subjected to hot pressing treatment, and the composite wave-absorbing film is obtained. Strontium ferrite and Ti < 3 > C < 2 > T < x > in the composite wave-absorbing film have a synergistic effect, so that the wave-absorbing frequency band is widened, and the wave-absorbing performance of the composite wave-absorbing film is improved.

The invention provides a method for preparing a high-frequency ultralow-loss soft magnetic composite material, and the method comprises the following steps: (1) iron alloy soft magnetic powder and ferrite powder are provided, the D50 particle size range of the iron alloy soft magnetic powder is 1-100 [mu] m, the average particle size of the ferrite powder is 1-100 nm, and the average particle size of the ferrite powder is 1-100 nm; the ferrite powder is prepared by a coprecipitation method; the mass ratio of the ferrite powder to the iron alloy soft magnetic powder is (0.05: 100)-(10: 100); (2) mixing and grinding the iron alloy soft magnetic powder and the ferrite powder in the step (1) for a period of time to obtain composite powder; (3) adding an adhesive into the composite powder in the step (2), uniformly mixing and granulating to obtain granulated composite powder; and (4) adding a lubricant into the granulated composite powder in the step (3), and mixing to prepare the high-frequency ultralow-loss soft magnetic composite material. According to the high-frequency ultra-low-loss soft magnetic composite material prepared by the invention, the hysteresis loss and the eddy-current loss of the composite material can be remarkably reduced.

The application relates to the technical field of permanent ferrite preparation, in particular to a method for preparing strontium ferrite by a multi-field coupling auxiliary molten salt method. First, a chemical coprecipitation method is improved to obtain a mixture containing an excess precipitant, inorganic salt and strontium ferrite precursor; then the mixture is subjected to heat treatment under multi-field coupling; finally, strontium ferrite powder is obtained after washing and drying. The application simplifies the chemical coprecipitation process, avoids Sr loss and realizes in-situ salt formation; a multi-element molten salt system is constructed during heat treatment, and an alkali-containing molten salt system with activation is proposed; in the molten salt liquid phase environment, multi-physical fields such as magnetic fields and ultrasonic vibration force fields are cooperated to control the orientation and growth of grains, new driving force and fast channels are provided for ion diffusion, and the rapid synthesis of strontium ferrite and the control of microstructure and size are realized in a low temperature and short time.

The present application provides an electromagnetic wave absorbing sheet having a small variation in the amount of electromagnetic wave absorption caused by temperature change. A first electromagnetic wave absorbing sheet includes a substrate composed of an organic substance and a powder supported in the substrate, the powder being composed of a MnZn ferrite powder, an aluminum powder, and a silicon carbide powder, when a volume ratio of the MnZn ferrite powder is set to V M , a volume ratio of the aluminum powder is set to V A , and a volume ratio of the silicon carbide powder is set to V S , a silicon carbide occupancy ratio R S represented by V M / (V A + V S + V S1 ) is 1.5% or more and 41% or less.

The invention relates to the technical field of electronic materials, in particular to a large-size high-dielectric-constant gyromagnetic ferrite substrate and a preparation method thereof.The preparation method comprises the following steps that S1, high-dielectric-constant Bi-YIG gyromagnetic ferrite powder and an additive are subjected to ball milling and mixing to prepare tape casting slurry; s2, defoaming the tape casting slurry, and carrying out tape casting to obtain a Bi-YIG gyromagnetic ferrite raw ceramic material strip; s3, cutting and laminating the raw ceramic material belt, performing hot isostatic pressing by using a warm isostatic press to obtain a raw ceramic blank sheet, and performing cold isostatic pressing on the raw ceramic blank sheet by using a cold isostatic press to obtain a compact raw ceramic blank sheet; and S4, stacking a plurality of the compact green ceramic pieces, placing Bi-YIG gyromagnetic ferrite polishing substrates with the same size as the green ceramic pieces between every two layers of compact green ceramic pieces as clamping pieces for separation, placing Bi-YIG gyromagnetic ferrite polishing cover pieces at the top ends, and finally placing the stacked green ceramic pieces on a setter plate.

The application discloses a high-entropy oxide loaded lanthanum ferrite gas-sensitive material and a preparation method and application thereof, and comprises the following steps: preparing lanthanum ferrite powder; dispersing the lanthanum ferrite powder in water, adding citric acid, and then performing ultrasonic treatment under ice water bath conditions to obtain a surface-modified base suspension liquid; under ice water bath and stirring conditions, dropping a high-entropy complex mother liquor into the base suspension liquid, then adding urea, and performing hydrothermal reaction to obtain a precipitate; washing and drying the precipitate, and then performing stepwise temperature increasing calcination in air. The sensor prepared from the gas-sensitive material has a low baseline resistance of 11 MΩ at an optimal working temperature of 180 DEG C, a response degree of 45.24 to 50 ppm of acetone, and an optimal working temperature which is reduced by 75 DEG C than that of a pure LaFeO3 sensor; the response and recovery times are shortened to 23.38 seconds and 8 seconds respectively, and the sensor exhibits excellent kinetic characteristics.

The utility model discloses a mixing device for soft magnetic ferrite powder, which is applied to the technical field of electronic material processing, and ensures that the powder can be fully rolled, collided and mixed in a cavity through periodic back-and-forth reciprocating swing of a processing bin in the process of stirring and mixing the powder in the mixing processing bin. Lubricating agent accumulation caused by gravity or centrifugal force difference in a specific area is avoided, and mixing blind areas at the two ends or the edge of the cylinder in traditional one-way rotation are eliminated; in the rotating direction switching process, the mixing effect among powder particles is enhanced, meanwhile, a lubricating agent is more uniformly dispersed into powder gaps in the bidirectional flowing process, the mixing efficiency and the material performance consistency are improved, and the local agglomeration or layering phenomenon is reduced.

The invention belongs to the technical field of educational toys, and relates to an anti-scattering magnetic adsorption jigsaw system. The system comprises a jigsaw picture, a flexible magnetic jigsaw plate and a magnetic jigsaw storage disc, ndFeB miniature permanent magnets are embedded in the back face of a base body of the The flexible magnetic jigsaw puzzle is prepared by mixing ferrite powder and flexible high polymer materials such as PVC or rubber, and can be curled and stored; a ferrite layer is embedded in the magnetic jigsaw storage disc, and an anti-slip high edge is arranged on the edge. And the jigsaw pieces are respectively in magnetic adsorption fit with the flexible magnetic jigsaw plates and the magnetic jigsaw storage disc through the permanent magnets on the back surfaces. According to the jigsaw puzzle, the risk that the jigsaw puzzles are scattered due to inclination or shaking can be effectively reduced in the jigsaw puzzle process, multiple jigsaw puzzle postures are supported, the jigsaw puzzles can be conveniently classified and stored, the whole jigsaw puzzle can be attracted to ferromagnetic metal surfaces such as a refrigerator door or a magnetic white board or a metal wall face after jigsaw puzzle is completed, and mounting-free display is achieved.

The invention discloses a ferrite phase shifter preparation method based on a ceramic 3D printing technology, and relates to the technical field of microwave devices, and the ferrite phase shifter preparation method comprises the following steps: mixing obtained pre-synthesized ferrite powder and photosensitive resin according to a certain proportion to form ceramic slurry; printing by using a 3D printer to obtain a phase shifter blank; uncured slurry left on the surface of the green body is removed, and the residual part is completely cross-linked and cured through an ultraviolet post-curing box; putting the post-cured green body into a vacuum degreasing furnace, and removing organic components in the green body; under the protection of a specific atmosphere, the ferrite blank is fully densified. According to the method, high freedom and optimal design of a geometric structure, light weight and topological optimization of the structure can be achieved, traditional manufacturing bottlenecks are broken through, the manufacturing efficiency can be improved, the production cost of complex components is reduced, and the method is particularly suitable for manufacturing ferrite elements with special shapes or microminiaturization and has wide application prospects. And a feasible manufacturing scheme is provided for a next-generation miniaturized and high-performance microwave module.

The present invention is a spherical Ni-based spinel ferrite powder having a circularity coefficient of 0.75 to 1.00, an average particle diameter D50 of 0.1 [mu] m to 200 [mu] m, and a dielectric constant of 1 to 13 at 50 MHz when 60 vol% of the ferrite powder is kneaded with a resin.

This invention relates to a method for preparing high-performance manganese-zinc ferrite powder, comprising: (1) mixing the main raw material, defoamer, deionized water and auxiliary raw material evenly, and then ball milling once to obtain a slurry; wherein the main raw material includes pre-calcined manganese-zinc ferrite powder; (2) adding a binder and a dispersant to the slurry, and ball milling a second time to obtain a uniform slurry; (3) conveying the uniform slurry to a spray drying tower for spray granulation to obtain the high-performance manganese-zinc ferrite powder. The high-performance manganese-zinc ferrite powder obtained by this invention has the advantages of uniform particle size, high sphericity, high fluidity and high compaction density, and the process has high consistency and stability and good reproducibility between different batches.

The invention provides ferrite powder for injection-molded magnets and a preparation method and application thereof, and relates to the technical field of magnets. Specifically, the ferrite powder comprises first magnetic powder, second magnetic powder and third magnetic powder, wherein the average particle size of the first magnetic powder is 4.0 [mu] m-8. 0 [mu] m, the average particle size of the second magnetic powder is 0.2 [mu] m-0. 8 [mu] m, and the average particle size of the third magnetic powder is 1.0 [mu] m-3. 0 [mu] m; and the third magnetic powder comprises yttrium oxide. According to the invention, yttrium oxide-doped unimodal normal distribution ferrite magnetic powder particles are introduced into a bimodal particle size distribution system in which coarse and fine magnetic powder particles are matched, so that a magnet system provides enough compression density, the magnetic powder has excellent melt fluidity, and higher orientation degree is realized in a low-intensity orientation magnetic field.