32 results about "Initial permeability" patented technology

The utility model relates to a zero sequence current transformer applied in the electrical field, which comprises an iron core made of ferromagnetic material with high initial permeability, a secondary winding is wound on the iron core, the outer side of the secondary winding is coated with a magnetic shielding layer, and the initial permeability of the ferromagnetic material in the magnetic shielding layer is higher than that of the iron core; the secondary winding is equally divided into a plurality of parts and then connected in series end to end, the output end of the secondary winding is connected with a plurality of divider resistors in series, each divider resistor is provided with a plurality of taps, and voltage output by each tap is subjected to data acquisition according to needs. And a voltage signal output by the tap with the highest amplitude but not exceeding a limit value is used as a standard basis. According to the utility model, main magnetic flux and leakage magnetic flux generated by primary current and secondary current of each phase are the same as much as possible, and unbalanced output is minimized.

The application provides a manganese-zinc ferrite material and a preparation method and application thereof. The manganese-zinc ferrite material can have an initial permeability μi of 1837 H / m or higher, a saturation magnetic induction intensity Bs of 572 mT or higher at 25 DEG C, and a saturation magnetic induction intensity Bs of 487 mT or higher at 100 DEG C through specific setting of a formula, so that the power conversion efficiency of an electronic component is improved.

The application discloses a kind of high-power radio frequency magnetron sputtering patterning preparation CoTaZr film and high-frequency performance regulation process, belongs to soft magnetic film preparation technical field.The application is with high-power radio frequency magnetron sputtering as core deposition process, stripe pattern is as characteristic regulation means, and the composition ratio of preparation patterned CoTaZr amorphous soft magnetic film is Co:89 at.%;Ta:5 at.%;Zr:6 at.% on Si (111) substrate;By 140W high sputtering power optimization film intrinsic structure and morphology, in combination with the mask plate induced shape anisotropy that stripe spacing is fixed at 50 μm, width 30 μm~70 μm, realize the synergic regulation of film high-frequency performance, surface morphology and resistivity.The application is carried out at room temperature, and compatible with standard CMOS process, the film cutoff frequency is continuously regulated at 2.19~3.06 GHz, saturation magnetization is stable at 12000~12500 Gs, initial permeability is 191~371 adjustable, surface roughness is 0.401~1.284 nm, resistivity keeps low loss characteristics, solve the problem that film morphology, resistivity and high-frequency performance are difficult to take into account in traditional process, can meet the application demand of GHz frequency band on-chip integrated inductor, 5G communication module and other high-frequency devices on magnetic core material.

The invention discloses a preparation method of a wide-range current transformer iron core, which comprises the following steps of: selecting a first ferromagnetic material strip with initial permeability mu i greater than 50,000 and a second ferromagnetic material strip with saturation flux density Bs greater than 1.8 T, the thickness of the first material being 15-30 microns, and the thickness of the second material being 0.10-0.30 mm; the strip is precisely cut, and the dimensional tolerance is controlled within + / -0.02 mm; the cut strip is subjected to surface insulation treatment, and an insulation coating of 1-3 microns is formed on the surface of the second material; the two materials are combined into an annular iron core in an alternate lamination mode, and an insulating layer smaller than 5 microns is arranged between layers; and carrying out multi-stage annealing treatment in a protective atmosphere, wherein the multi-stage annealing treatment comprises a 300-450 DEG C destressing stage, a recrystallization stage and a 400-500 DEG C magnetic field annealing stage. According to the iron core manufactured by the method, the ratio error is less than 0.5% and the angular difference is less than 20 minutes within the rated current range of 0.1-200%, so that wide-range and high-precision measurement is realized, and a reliable technical basis is provided for accurate measurement of a power system.

The invention discloses a preparation method for improving the initial permeability of permalloy, which is based on Fe-Ni-Mo permalloy and adopts a ternary synergistic process of electron beam smelting, ultra-large cold rolling deformation and magnetic field heat treatment. The permalloy strip with the ultrahigh initial permeability is prepared through the method, three microscopic barriers including an impurity pinning barrier, a grain boundary and defect barrier and an intrinsic magnetic barrier which limit the magnetic performance of permalloy are overcome, the permalloy strip with the ultrahigh initial permeability is obtained, and the method has the advantages of being simple in process, low in cost, easy to produce in batches and the like, and can well meet the requirements of high-end electromagnetic elements.

In the present invention, by using metal magnetic particles having a circularity of 0.7 or more in an inductor, initial permeability can be improved and DC superposition characteristics can be improved.　This inductor comprises: a coil conductor including a winding part around which a conductive wire is wound and a pair of lead-out parts led out from the winding part; an element body that contains metal magnetic particles and a resin and includes the coil conductor; and an external electrode formed on the surface of the element body and connected to the lead-out part of the coil conductor. The metal magnetic particles have a circularity of 0.7 or more. The metal magnetic particles having no more than a 20° adjacent angle, which is formed by a line between adjacent metal magnetic particles and a line in the thickness direction of the element body, are present at an accumulation frequency of 20% or more in a portion of the element body surrounded by the winding part of the coil conductor.

The application discloses a DC superimposition-resistant and wide-temperature low-loss MnZn ferrite and a preparation method and application thereof. The MnZn ferrite main material is prepared according to the required raw material weight of 52.3-53.3 mol% of Fe2O3, 35.2-36.2 mol% of MnO, 0.12-0.18 mol% of TiO2 and the balance of ZnO; the additive is prepared by mixing 0.12-0.16 wt% of CaCO3, 0.02-0.04 wt% of SiO2, 0.03-0.04 wt% of V2O5, 0.12-0.18 wt% of Co2O3 and 0.1-0.3 wt% of SrTiO3 nano powder; the main material is put into a ball mill for primary ball milling mixing, and then is dried and pre-sintered; the pre-sintered powder and the additive are simultaneously put into the ball mill for secondary ball milling, and then are dried and granulated, and are formed into annular green bodies, and the ferrite is obtained by sintering the annular green bodies. The MnZn ferrite material with high DC superimposition resistance and low loss can be prepared, the initial permeability is 2933, the DC superimposition magnetic field value corresponding to a 70% reduction of the permeability is 200 A / m, the loss is lower than 330 kW / m μ70 at 100 kHz and 200 mT in the range of 25-100 DEG C. 3 ​

This invention discloses a low-temperature sintering NiCuZn ferrite material with high initial permeability and low power loss, and its preparation method. It belongs to the technical field of ferrite material preparation for LTCF inductors, and includes a main component and additives. The main component has the molecular formula Ni. 0.23‑x Cu 0.22+ x Zn 0.55 Fe2O4, x=0.01~0.04; based on the mass of the main component, the additives include: 0.4~0.9 wt% V2O5, 0.1~0.3 wt% Sb2O3. This invention employs a combined V2O5-Sb2O3 additive, whose synergistic effect provides more liquid-phase sintering sites for the liquid-phase sintering process, promotes sintering densification, and improves various magnetic properties of NiCuZn ferrite, achieving comprehensive optimization of permeability, saturation magnetic induction, and power loss at MHz-level frequencies.

The invention discloses a ferromagnetic material sleeve for anti-icing of an alternating-current power transmission line and a deicing method, the sleeve is of an annular split structure with an opening in the axial direction and is formed by splicing two symmetrical semi-ring pieces, the semi-ring pieces are made of iron-nickel alloy materials, and an integrated cylindrical magnetic circuit is formed after the semi-ring pieces are spliced; connecting structures are arranged on the two sides of the axial openings of the semi-ring pieces and used for achieving mutual connection between the two semi-ring pieces in the assembling process. The inner wall of each semi-ring piece is provided with a heat-conducting insulating lining which is used for achieving heat conduction and electric insulation of the sleeve to the power transmission conductor. The ferromagnetic material sleeve has extremely high initial permeability and extremely low coercive force under power frequency, strong coupling and low-loss transmission of a wire magnetic field can be achieved, and the sleeve is not saturated early and can output thermal power under large current. The sleeve can be quickly assembled on an alternating-current power transmission wire to form a closed magnetic circuit under the condition of no power failure, so that magnetic flux is converted into hysteresis heat, and the sleeve is used for preventing icing of a power transmission line.

The invention discloses a method for testing clay permeability along with temperature change, and relates to the technical field of soil body testing. According to the method, the change of the clay permeability along with the temperature is analyzed through a nuclear magnetic resonance technology, firstly, the initial permeability of a soil sample is measured and subjected to vacuum saturation, and then nuclear magnetic resonance relaxation signals are collected at different constant temperatures of 30-60 DEG C; a quantitative relation between temperature and nuclear magnetic signal intensity is established through a dry fine sand calibration experiment, and a relaxation spectrum signal is converted into water mass. And finally, calculating the permeability of the clay at different temperatures based on the fitting slope of the T2 spectrum logarithmic mean value and the temperature. According to the method, lossless quantitative evaluation of the clay permeability under the influence of the temperature is realized. According to the present invention, the fluidity of the water molecules in the cohesive soil can be determined based on the low-field nuclear magnetic resonance technology, the determination method only needs the determination of the initial permeability without the long-time penetration test after the temperature change every time, and the advantages of rapidness and high efficiency are provided.

The invention discloses a magnetic conductivity initial value prediction method for improving motor finite element analysis and calculation efficiency, and belongs to the technical field of motor design and electromagnetic field numerical calculation. The problem of improving the solving speed of a motor finite element model is solved. The method comprises the steps of establishing a stator side equivalent magnetic circuit model; establishing a rotor side magnetic field distribution prediction model for predicting air gap magnetic field distribution under different rotor topological structures; constructing a rotor side equivalent magnetic circuit model based on air-gap magnetic field distribution under different rotor topological structures predicted by a rotor side magnetic field distribution prediction model, and then solving by combining the stator side equivalent magnetic circuit model and the obtained rotor side equivalent magnetic circuit model. And obtaining magnetic conductivity approximate distribution data of a motor iron core area as an initial value, substituting the initial value into the finite element model of the motor, and carrying out iterative solution to obtain a motor electromagnetic performance analysis result. The method effectively solves the problems that in traditional finite element analysis, due to blind setting of the initial magnetic conductivity, the number of non-linear iterations is large, and calculation time is long.

According to the low-cost high-magnetic-conductivity high-magnetic-shielding magnetically soft alloy and the preparation method thereof, Fe-Si-Al is adopted as a basic system, microalloying elements such as B and Nb are creatively introduced, specific critical cold rolling and magnetic field heat treatment processes are adopted, and the obtained magnetically soft alloy has high magnetic conductivity and high magnetic shielding effectiveness. Wherein the resistivity of the alloy is effectively improved and the magnetocrystalline anisotropy is optimized through the synergistic effect of Si and Al; the grain boundary segregation effect of the B element purifies the grain boundary, and the moving resistance of the magnetic domain wall is remarkably reduced; and the dispersed precipitated phase formed by the Nb element effectively refines the initial crystal grains and lays a foundation for subsequent formation of uniform and thick recrystallized crystal grains. Particularly, a strong Gaussian texture is induced through accurately controlled critical cold rolling deformation, and magnetic domains are directionally arranged in an easy magnetization direction in combination with magnetic field heat treatment applied near a Curie point, so that the coercive force is fundamentally reduced, and the initial magnetic conductivity is improved.

The invention relates to a wide-temperature, low-temperature-coefficient and high-permeability soft magnetic ferrite material, and belongs to the technical field of electronic ceramic materials. The material is composed of main components and auxiliary components, wherein the main components comprise Fe2O3, ZnO and MnO; and the auxiliary components comprise Bi2O3, MoO3, CaCO3 and CoO. The preparation method comprises the following steps: pre-sintering the main components, carrying out ball milling on the main components and the auxiliary components, granulating, carrying out compression molding, and sintering under a specific atmosphere curve. Through the magnetocrystalline anisotropy compensation effect of CoO and in combination with the co-sintering of Bi2O3 / MoO3 and the grain boundary regulation and control effect of CaCO3, the excellent comprehensive performance that the initial magnetic conductivity of the material can reach 6500 within the extremely wide temperature range of-50 DEG C to 170 DEG C, the temperature coefficient alpha F of the material is-0.5-0.5 at the temperature of-50 DEG C to 50 DEG C, and the alpha F of the material is 0-1 at the temperature of 50 DEG C to 80 DEG C is achieved synergistically.

The application discloses a high-frequency low-loss composite magnetic core material and a preparation method and application thereof, and particularly relates to the technical field of soft magnetic composite materials; the composite magnetic core material is prepared from a base component and a doping component through pre-burning, pressing and sintering; the base component comprises Fe2O3, MnO and ZnO; the doping component comprises BiFeO3, SrTiO3, WO3, Co2O3, CaCO3, Nb2O5 and V2O5; the application optimizes the synergistic effect of the base component and the doping component, suppresses the loss, improves the initial magnetic permeability, realizes the balance between the high frequency and the low loss and the high magnetic permeability, and meets the high-performance requirement of high-frequency power electronic devices on the magnetic core material.

The invention discloses a high-performance ferrite core as well as a preparation method and application thereof. The preparation method comprises the following steps: weighing Fe2O3, Mn3O4, ZnO and a small amount of additives according to specific parts by mass, carrying out primary ball milling and pre-sintering, adding an ammonium polyacrylate dispersing agent in secondary ball milling, and controlling the pH value to obtain superfine slurry with D50 of 0.5-1.0 mu m; adding a polyvinyl alcohol adhesive, and carrying out spray granulation and high-pressure molding to obtain a green body; and finally, carrying out staged sintering in a controllable atmosphere, fully discharging glue at 400-600 DEG C, and carrying out heat preservation sintering at 1250-1350 DEG C under the oxygen partial pressure of 1.0-5.0%. The prepared magnetic core is uniform and fine in grain, the average size is 3-10 microns, the initial magnetic conductivity reaches 3200-3800 under 100 kHz, the saturation magnetic flux density is larger than or equal to 510 mT, and the power loss is smaller than or equal to 350 kW / m < 3 > under the conditions of 100 kHz, 200 mT and 100 DEG C. The magnetic core is suitable for a power transformer and an inductor of a 100kHz-1MHz high-frequency switching power supply, and has high magnetic conductivity, high saturation magnetic flux density and extremely low loss.

Multi-layered shielded cabin that an outer shell (2) with a first soft magnetic alloy having an initial permeability µ i1 and a maximum permeability µ max1 exhibits an inner shell (3) with a second soft magnetic alloy having an initial permeability µ i2 and a maximum permeability µ max2 exhibits, exhibits where µ i denotes the initial permeability at a control output of H=0.1 A / m, and wherein the outer shell (2) encloses the inner shell (3) and µ max1 > µ max2 and µ i2 > µ i1 .

Provided in the present application are a low-iron-loss dual-coated soft magnetic composite material and a preparation method therefor. Raw materials for preparation comprise an insulated coated magnetic powder, a binder and a mold release agent. The insulated coated magnetic powder comprises a SiO2-coated magnetic powder and a boron oxide insulating coating layer with which the surface of the SiO2-coated magnetic powder is coated; the SiO2-coated magnetic powder comprises a metal magnetic powder and a SiO2 insulating coating layer with which the surface of the metal magnetic powder is coated; and the metal magnetic powder comprises a first metal magnetic powder Fe-Si-Ge-R1 and a second metal magnetic powder Fe-Si-Al-C-R2. The low-iron-loss dual-coated soft magnetic composite material prepared by the present application has low losses at medium- and high-frequencies, and also has high initial permeability, thus making it suitable for electrical equipment such as transformers and reactors.

This invention discloses a near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device, comprising an overhead power transmission line, a lightweight magnetic core, and a cavity; the lightweight magnetic core is placed inside the cavity, and the overhead power transmission line is located above the cavity; the lightweight magnetic core is made of a hollow rectangular thin-walled structure of soft magnetic material with high initial permeability, and is set inside the shell on the side near the overhead power transmission line. The soft magnetic material with high initial permeability efficiently concentrates the power frequency alternating magnetic field around the overhead power transmission line. The shell (9) is a hollow inner cavity structure, which achieves magnetic shielding protection for the internal space. This invention is a high initial permeability composite thin-shell device, which enables the thin shell itself to simultaneously perform magnetic field energy harvesting and internal magnetic shielding.

This invention discloses a method for preparing a composite magnetic core material. The method involves pretreating Fe-Si-B-Nb-Cu nanocrystalline / amorphous dual-phase powder, coating it with aluminum phosphate, mixing it with MnZnFe2O4 ferrite powder in a specific ratio, adding an organic binder, pressing it into shape, and then curing it with aluminum phosphate at 425–435°C. This temperature window allows for sufficient curing of the aluminum phosphate coating layer, forming a strong inorganic bond, while effectively inhibiting nanocrystalline grain growth, increasing volume resistivity, reducing eddy current losses, and avoiding changes in the ferrite phase structure. The resulting material has Fe-Si-B-Nb-Cu nanocrystals with a grain size of 10–15 nm, an aluminum phosphate coating layer thickness of 5–10 nm, an initial permeability of 800–1200 at 100 kHz, and a power loss of less than 300 kW / m. 3 The volume resistivity is 10 2 ~10 3 With a strength of Ω·m and a bending strength of not less than 80MPa, it has excellent overall performance and is suitable for high-frequency power electronic devices.

The application discloses a kind of based on magnetic property prediction electrical equipment material selection method, device, equipment and storage medium, belong to magnetic material selection technical field, the method is: according to the function structure requirement of electrical equipment determines electrical equipment type, work capacity and working frequency, and then selects multiple applicable magnetic materials in preset database;Respectively obtain the chemical composition and physical structure parameters of each applicable magnetic material, and obtain the working temperature, working condition data and magnetic property requirement of electrical equipment;For each applicable magnetic material, based on working temperature, working condition data, and corresponding chemical composition and physical structure parameters, magnetic property prediction is carried out, and predicted magnetic induction, predicted iron loss and predicted static relative initial permeability are obtained;Based on the magnetic property data predicted from each applicable magnetic material and the magnetic property requirement, determine the optimal magnetic material in multiple applicable magnetic materials.The application can solve the problem of low accuracy of magnetic material selection in the prior art.

The application discloses a preparation process of an elliptical ring-shaped nanocrystalline alloy iron core with high initial permeability, and comprises the following specific steps: S1, designing the iron core and a mold thereof; S2, winding amorphous alloy ribbons into a circular ring-shaped iron core according to the size and volume of the iron core; S3, placing the circular ring-shaped iron core into the mold; S4, placing the mold with the circular ring-shaped iron core into a vacuum annealing furnace to perform vacuum crystallization annealing; S5, after the annealing is completed, taking out the annealed circular ring-shaped iron core from the mold, placing the annealed circular ring-shaped iron core into an elliptical ring-shaped stainless steel protective box, and pouring silicon rubber to package the elliptical ring-shaped stainless steel protective box; and S6, measuring V-A characteristics by using an iron core performance measuring instrument, and calculating the initial permeability from the V-A data, compared with the prior art, the application offsets the deformation in the crystallization process by pre-deformation before annealing and mold shrinkage during the annealing process, greatly reduces internal stress, and obtains high initial permeability; uniform deformation of the elliptical ring-shaped iron core can be realized, and the elliptical ring shape is maintained after the annealing.

The application discloses a soft magnetic composite material, which comprises a first soft magnetic metal powder, a first insulating coating material and airflow broken granulation powder. The airflow broken granulation powder comprises a second soft magnetic metal powder and a second insulating coating material, and the second insulating coating material is completely solidified. The first insulating coating material and / or the second insulating coating material in the soft magnetic composite material is uniformly dispersed, the soft magnetic composite material is used for preparing a metal powder core and a molded inductor, and the prepared molded inductor has higher insulation resistance and initial magnetic permeability. Accordingly, the application further discloses a preparation method of the soft magnetic composite material, the first insulating coating material and / or the second insulating coating material in the prepared soft magnetic composite material is uniformly dispersed, and the operation is simple and the cost is low. Accordingly, the application further discloses a metal powder core and a preparation method thereof, and a molded inductor and a preparation method thereof.

The invention discloses a firmly-welded patch common-mode inductor with a terminal on the side face and a preparation process thereof, and belongs to the technical field of patch common-mode inductor preparation, and the preparation process comprises the following steps: S1, selecting a bare magnetic core with the initial magnetic conductivity of nickel-zinc ferrite being 10-2000 uiac and the initial magnetic conductivity of manganese-zinc ferrite being greater than 2000 uiac, and cleaning and drying the bare magnetic core; s2, high-temperature-resistant high-strength epoxy resin glue is used for pasting the Clip on the magnetic core, the curing temperature is 150 DEG C, the curing time is 90 min, and the position precision of the Clip is guaranteed through a positioning tool; and S3, the magnetic core pasted with the Clip is subjected to Ni / Sn electroplating treatment, and the electroplating thickness is that Ni is 2-4 [mu] m, and Sn is 7.0 [mu] m min. In the welding optimization link, reflow soldering furnace tin soldering operation is adopted, the solder paste component proportion and the welding temperature curve are accurately controlled, the stability of a product is greatly improved, and the service life of the product is greatly prolonged.

The invention relates to the technical field of equivalent conductivity testing, and discloses a non-continuous conductive layer equivalent conductivity testing system and method based on simulation inversion and a medium, and the system comprises a testing module which is used for testing a first testing sample corresponding to a magnetic conductive layer of a tested magnetic shielding device to obtain each conductivity, the acquisition module is used for acquiring the initial magnetic conductivity of the second test sample under different magnetic field frequencies and acquiring the actual magnetic field intensity of the tested magnetic shielding device in the magnetic shielding space under different magnetic field frequencies and different excitation magnetic field intensities; the processing module is used for determining intrinsic conductivity, a first relation curve and a second relation curve on the basis of each conductivity acquired from the test module, the initial magnetic conductivity under different magnetic field frequencies and the actual magnetic field intensity in the magnetic shielding space under different magnetic field frequencies and different excitation magnetic field intensities, and performing inversion optimization by using a preset simulation model to obtain a simulation result; and obtaining the target equivalent conductivity of the non-continuous conductive layer of the tested magnetic shielding device.

This invention provides a coil-encapsulated core and coil component that can simultaneously achieve improved insulation and improved initial permeability. One coil-encapsulated core comprises magnetic powder and resin and encapsulates a coil made of conductor, and also contains a modifier.

The application discloses a kind of low-loss wide-temperature manganese-zinc ferrite materials and preparation process thereof, belong to magnetic material technical field.Prepared by the following raw materials: Fe2O3 45-55 parts, Mn3O4 20-30 parts, ZnO 15-25 parts, Mg-V-Si in-situ reaction type composite dopant 2-4 parts, CaCO3 0.5-1.5 parts, Nb2O 5 0.1-0.3 parts, surfactant 0.2-0.8 parts, forming aid 1-2 parts.By preparing Mg-V-Si composite dopant, combined with three-step gradient temperature + double-platform gradient cooling sintering process, the material obtained in-40 DEG C to 180 DEG C wide temperature range power loss ≤308 kW / m³, initial permeability ≥3720, saturation magnetic induction intensity ≥542 mT, Curie temperature ≥258 DEG C, can meet the stringent demand of new energy vehicles, aerospace and other fields to wide-temperature low-loss magnetic material.

A coil-embedded magnetic core capable of achieving improvements both in insulation and initial magnetic permeability, and coil devices thereof. The coil-embedded magnetic core embedding a coil made of a conductor, including magnetic powder and a resin, in which the coil-embedded magnetic core further includes a modifier.

The invention relates to the technical field of soft magnetic materials, and discloses a high-initial-permeability iron-based nanocrystalline magnetic core and a preparation method thereof. Alloy components of the magnetic core comprise, by atomic percent, 70%-75% of a, 0.8%-1.2% of b, 2.7%-3.2% of c, 15%-17% of d and 8%-10% of e, and the sum of d and e is 25%. The preparation method comprises the following steps: smelting the raw materials into a master alloy according to the component proportion, preparing an amorphous strip by adopting a single-roller quenching method, winding to form the magnetic core, adopting sectional heat treatment, and applying an alternating magnetic field within a time period from the beginning of first-section heat preservation to 10 minutes before second-section heat preservation. And meanwhile, good comprehensive soft magnetic performance is kept, and the composite material is suitable for being widely applied to the fields of power transformers or transformers and the like.

The invention relates to a high-frequency wide-temperature low-loss MnZn ferrite material and a preparation method thereof. Comprising the following steps: S1, adding MnZn ferrite particles and SrTiO3 powder into ethanol, stirring, and drying to obtain modified MnZn ferrite particles; and S2, pressing the modified MnZn ferrite particles into a magnetic ring, sintering the magnetic ring at 1150-1250 DEG C in a nitrogen-oxygen mixed atmosphere for 25-35 minutes, and cooling the magnetic ring to obtain the high-frequency wide-temperature low-loss MnZn ferrite material. According to the invention, a novel dopant SrTiO3 is developed, and the dopant affects the microstructure and the electromagnetic performance of the MnZn ferrite, so that the initial permeability is improved while the eddy-current loss and the residual loss are limited. The use performance of the MnZn ferrite material is effectively improved, and the problems of high energy consumption in the MnZn ferrite material production process and high high-frequency loss of the conventional MnZn ferrite material are solved.

The invention discloses a preparation process of a soft magnetic iron core bar for a pump, and belongs to the technical field of preparation of soft magnetic composite materials. According to the process, the oxygen partial pressure is controlled to be 100-800 ppm under the inert atmosphere, so that an inner layer of 2-10 nm is selectively formed on the surface of Fe-Ni-Mo-Nb alloy powder; then coating with GPTMS sol with the pH value of 4-5 to form an outer layer with the thickness of 10-60nm, so as to obtain core-shell powder; mixing the core-shell powder with a dual-curing binder, heating to 110-130 DEG C to reduce the viscosity, and cooling to 60-80 DEG C to enable the viscosity to reach 50-150 Pa.s; performing injection molding in an axial alternating magnetic field of 50-200Hz and 0.2-0.6 T, completing synchronous defoaming and axial orientation, performing UV instantaneous curing in the presence of the magnetic field, and then performing thermocuring to obtain the bar. The ratio of the axial initial permeability to the radial initial permeability of the obtained bar is larger than or equal to 1.15, the coercive force Hc is smaller than or equal to 30 A / m, the volume resistivity is larger than or equal to 1 * omega.cm, and the method is suitable for the fields of electromagnetic drive pumps and the like.