173 results about "Remanence" patented technology

The invention discloses a neodymium-iron-boron magnet with double main phases and light rare earth diffusion based on asymmetric cerium distribution and a preparation method, and relates to the technical field of neodymium-iron-boron magnets. The method comprises the steps that a diffusion matrix is prepared through a double-main-phase technology, in the double-main-phase technology, the components of a main-phase alloy and an auxiliary-phase alloy are RaCebFe100-a-b-c-dMcBd, R is PrNd alloy or Nd metal, M is at least one of Cu, Al, Zr, Co and Ga, the content of Ce in the main-phase alloy is larger than that of Ce in the auxiliary-phase alloy, then the upper surface and the lower surface of the diffusion matrix are coated with a diffusion source solution, and the diffusion matrix is obtained through heat treatment. Carrying out heat treatment and aging treatment to obtain a neodymium-iron-boron magnet; the diffusion source solution is formed by mixing a diffusion source and a solvent, and the diffusion source is (PrmNdn) aAlbCucZrdCoeMgf. The neodymium-iron-boron magnet obtained through the method has high residual magnetism and high coercive force at the same time, the diffusion efficiency of the diffusion source is high, and the rare earth utilization rate is increased.

The invention discloses a fault signal dual-mode output method of a magnetic latching relay, particularly relates to the technical field of relay control, and is used for solving the problem of low mode switching efficiency caused by an existing physical jumper mechanism. The current mechanical state of the relay is detected by receiving a remote dual-mode switching instruction; applying a driving voltage sequence corresponding to the target mode according to the state; based on the iron core residual magnetism intensity and the dynamic margin of a target mode nominal value, judging and generating a driving enabling or degaussing trigger signal; when a driving enable signal is responded, the lag time difference between the voltage rising edge and the magnetic flux jump starting point is captured in real time, and the eddy current loss characterization quantity is generated by combining the product integration of the current differential and the temperature rise; adjusting the rising slope and the duty ratio of the driving voltage sequence according to the lag time difference and the over-limit condition of the eddy-current loss characterization quantity; and finally, the matching between an execution result and a target mode identifier is verified by controlling a coil current response waveform, and the continuous holding mode and the instantaneous pulse mode are remotely and reliably switched.

The invention discloses a method for measuring and analyzing residual magnetism characteristics of an iron core. According to the method, a to-be-detected iron core is demagnetized, preset residual magnetism is set, direct-current voltage excitation with opposite polarities, the same amplitude and the same duration is applied to a primary winding of the to-be-detected iron core, and transient current response signals are synchronously collected; two groups of current under positive / negative polarity excitation are extracted, and the residual magnetism direction is judged by comparing the change rate of the current; a curve of equivalent resistance changing along with time is calculated based on forward current and voltage, a resistance value corresponding to a characteristic inflection point moment is selected, the resistance value is substituted into a pre-established residual magnetism-equivalent resistance empirical formula to deduce the magnitude of residual magnetism, and a matched iron core residual magnetism detection and demagnetization integrated system integrates information management, residual magnetism detection, demagnetization and display modules. And closed-loop automation of detection, analysis and demagnetization is realized. According to the method, a magnetic field sensor is not needed, the residual magnetism direction and size can be synchronously obtained in a high-precision and robust mode only through port electric signals, and the method is suitable for on-site off-line or live detection.

The invention discloses a high-magnetic-performance neodymium-iron-boron magnet and a preparation method thereof, and belongs to the technical field of magnetic materials. The technical problem that an existing magnet is low in magnetic performance is solved. The invention provides a preparation method of a high-magnetic-performance neodymium-iron-boron magnet. The preparation method comprises the following steps: S1, preparing neodymium-iron-boron powder A and neodymium-iron-boron powder B by adopting a vacuum melting method; s2, carrying out powder mixing and orientation compression treatment; s21, powder mixing treatment, wherein the neodymium-iron-boron powder A and the neodymium-iron-boron powder B are mixed, and evenly-mixed neodymium-iron-boron powder is obtained; s22, orientation treatment, wherein the evenly-mixed neodymium iron boron powder is placed in a magnetic field with the magnetic field intensity larger than 2.0 T to be subjected to orientation forming, and a neodymium iron boron blank is obtained; and S3, carrying out sintering treatment and two-stage aging treatment on the prepared neodymium-iron-boron blank to finally obtain the neodymium-iron-boron magnet with high magnetic performance. The residual magnetism of the neodymium-iron-boron magnet prepared by the method disclosed by the invention is 14.21 kGs or above.

The application discloses a large-size rare earth permanent magnet material and a preparation method thereof. The preparation method of the large-size rare earth permanent magnet material comprises the following specific steps: pretreating a base magnet blank; performing sputtering treatment on the pretreated magnet; and performing heat treatment on the magnet after the sputtering treatment to obtain the required rare earth permanent magnet material. The application provides a batch preparation method suitable for large-size (width greater than 20 mm) sintered neodymium-iron-boron permeation. The application is used to improve the magnet performance, on one hand, the product performance can be effectively improved (compared with the base magnet blank, the coercive force is increased by 6930Oe-9990Oe, and the remanence is reduced by 220Gs-340Gs), on the other hand, the batch product with qualified appearance and meeting the performance requirements can be output, and the burr defects of the large-size product can be avoided.

The invention discloses a sintered neodymium-iron-boron permanent magnet material with a low coercive force temperature coefficient for a new energy automobile, and relates to the technical field of sintered neodymium-iron-boron permanent magnet materials. Collaborative optimization of high residual magnetism and high coercive force is realized through preparation of the sintered neodymium-iron-boron permanent magnet material; the performance bottleneck of a traditional sintered neodymium-iron-boron magnet material is broken through, and the energy density and the demagnetization resistance of the magnet are doubly improved, so that the magnet is excellent in high-temperature and high-intensity magnetic field environments.

The application relates to the technical field of magnetic materials, in particular to a preparation method of high-performance heavy-rare-earth-free neodymium iron boron magnets; the preparation method comprises the following steps: rapidly quenching a main phase alloy into a flake, obtaining coarse powder after hydrogen breaking; immersing the coarse powder in an ethanol mixed solution containing lanthanum nitrate and cerium nitrate, drying the pretreated coarse powder after ultrasonic-magnetic stirring cooperative treatment; adding an antioxidant and a lubricant into the pretreated coarse powder, preparing fine powder with an average particle size of 2-3.5 microns through airflow milling; performing magnetic field orientation compression molding on the fine powder under nitrogen protection, improving the density through cold isostatic pressing; finally, performing vacuum sintering and step-by-step tempering treatment to obtain the high-performance heavy-rare-earth-free neodymium iron boron magnets; wherein the main phase alloy is composed of the following components with mass percentage: 28-31wt.% Pr25Nd75, 0.88-1.2wt.% B, 0-0.1wt.% Al, 0.05-0.3wt.% Ti, 0.05-0.4wt.% Cu, 0.5-1.4wt.% Co, 0.1-0.4wt.% Ga, and the balance is Fe; the prepared neodymium iron boron magnet has the dual characteristics of high coercivity and high remanence, and effectively guarantees the performance and quality.

This application provides a neodymium iron boron magnet and its preparation method. The method includes: cutting a heavy rare earth-free magnet into a substrate with a predetermined size, wherein the composition of the heavy rare earth-free magnet is Pr and Nd for LRE, and one or more elements selected from Cu, Ga, Ti, Zr, Al, Co, and Nb, and the size of the substrate in the diffusion direction is less than or equal to 3 mm; pre-diffusion treatment of the substrate using a pre-diffusion source to obtain a pre-diffusion substrate, wherein the composition of the pre-diffusion source is as follows; preparing a diffusion slurry using a diffusion source alloy, wherein the composition of the diffusion source alloy is one or two elements selected from Dy and Tb for HRE, and one or more elements selected from Al, Cu, and Ga; and diffusion treatment of the pre-diffusion substrate using the diffusion slurry to obtain the neodymium iron boron magnet. By pre-diffusion and controlling the composition and content of the diffusion source alloy, the heavy rare earth elements diffuse only on the magnet surface during diffusion treatment, thus achieving both high remanence and high coercivity.

The application belongs to the technical field of ferrite material preparation, and particularly provides a modified self-biased hexagonal gyromagnetic ferrite material and a preparation method thereof. The modified self-biased hexagonal gyromagnetic ferrite material comprises a main component and an additive. The main component comprises 74.5 mol% to 82.8 mol% of Fe2O3, 1.3 mol% to 6.1 mol% of Cr2O3, and the rest of BaCO3. Taking the weight of the main component after pre-sintering as a calculation basis, the additive comprises 0.5 wt% to 2.0 wt% of CaCO3, 0.5 wt% to 2.0 wt% of SiO2, and 0.1 wt% to 2.0 wt% of Bi2O3. The modified self-biased hexagonal gyromagnetic ferrite material (BaM) prepared through a sintering process optimization has the characteristics of high saturation magnetization (4πM s : 3.9~4.2kGs), high remanence ratio (M r / M s : 0.6~0.8), coercivity (H c : 450~550Oe), and low ferromagnetic resonance line width (ΔH: 230~280Oe), and meets the engineering requirements of microwave devices.

The application provides a residual magnetism estimation method and device for a three-phase transformer and electronic equipment. The estimation method comprises: for any single-phase transformer in the three-phase transformer, obtaining the voltage amplitude U m , the angular frequency ω of the power supply and the primary-side coil turn number N1; calculating the residual magnetism amplitude Φ m according to the voltage amplitude U m and the angular frequency ω of the power supply in combination with formula (1); obtaining the voltage closing angle α, the opening-starting time t open and the opening-ending time t open + Δt of the single-phase transformer at no-load opening; and calculating the residual magnetism Φ r of the single-phase transformer after opening according to the residual magnetism amplitude Φ m , the voltage closing angle α, the opening-starting time t open and the opening-ending time t open + Δt in combination with formula (2). The application calculates the residual magnetism Φ r of the single-phase transformer after opening in combination with formula (2), thereby replacing the complex integral term containing U C , reducing the calculation difficulty, and optimizing the accuracy of the residual magnetism estimation method for the transformer.

The application discloses a neodymium-iron-boron magnet material and a preparation method thereof, and an electronic device containing the same. The neodymium-iron-boron magnet material comprises the following components: R: 28.0-32.0 wt%, R comprises Nd, R further comprises Tb and / or Dy, the content of Nd is greater than or equal to 27.0 wt%; Cu: 0.16-0.40 wt%; Ga: 0.07-0.24 wt%; Al: less than or equal to 0.10 wt%; B: 0.96-1.10 wt%; Co: 0.15-2.0 wt%; M: 0.10-0.25 wt%, M is selected from at least one of Ti, Zr and Nb; and a phase with a chemical composition of R w Fe 100‑w‑x‑y‑z Co x Cu y Ga z is contained in the two-particle grain boundary of the neodymium-iron-boron magnet material. The neodymium-iron-boron magnet material in the application can realize a significant improvement in coercive force under the condition of adding a small amount of heavy rare earth element Tb, while maintaining a high remanence and squareness.

The invention provides a transformer residual magnetism detection method for improving direct current demagnetization, and belongs to the technical field of power equipment detection. The method comprises the following steps: demagnetizing a transformer iron core to eliminate an interference magnetic field, applying direct current excitation through a special winding to generate controllable preset residual magnetism, establishing a detection circuit in which a primary side winding is connected with an external resistor in series and a secondary side winding is open-circuited, and sequentially applying direct current small signal excitation with the same size and opposite directions, the method comprises the following steps: collecting forward and reverse transient current and voltage waveforms, comparing current change rate after filtering to judge the residual magnetism direction, solving the equivalent resistance of an iron core based on the waveform consistent with the residual magnetism direction, obtaining a detection result by combining the monotone fitting relationship between the resistance and residual magnetism, and finally assisting verification and calculating a relative error through an energy method. And if the error does not exceed 5%, it is determined that detection is effective, accurate and lossless detection of the magnitude and direction of the residual magnetism can be achieved, and detection reliability and engineering applicability are effectively improved.

The application discloses a hybrid permanent magnet structure design method for reducing vibration of a permanent magnet motor, and solves the problem of excessive vibration of the permanent magnet motor. The method is to adopt two or more kinds of permanent magnet materials with different residual magnetism densities, adopt appropriate parameters to combine into a required hybrid permanent magnet, and magnetize the hybrid permanent magnet with the maximum residual magnetism density during magnetization. After the permanent magnet motor adopts the hybrid permanent magnet structure, the harmonic content of the permanent magnet magnetic field can be significantly reduced, the sinusoidal degree of the motor air gap magnetic field is improved, and then the low space order radial electromagnetic force density generated by the action of the permanent magnet magnetic field is weakened, the electromagnetic vibration of the motor is reduced, and the problem of excessive vibration of the motor is obviously improved.

The invention discloses a rotor composite magnetic pole of an axial magnetic flux permanent magnet synchronous motor, which comprises a plurality of sector-shaped magnetic pole units uniformly distributed on one surface of a rotor core along the circumferential direction, and each magnetic pole unit comprises three sector-shaped permanent magnets with equal thickness and different magnetic properties, the second permanent magnet and the third permanent magnet are symmetrically arranged by connecting one right-angle side with the two isosceles sides of the first permanent magnet, the residual magnetic induction intensity of the three permanent magnets is low-high-low arrangement, and the connecting faces of the second permanent magnet and the first permanent magnet and the connecting faces of the third permanent magnet and the first permanent magnet are inclined faces inclined to the magnetizing direction. And gaps are formed between adjacent magnetic pole units. The rotor composite magnetic pole is combined with high and low residual magnetism materials through the inclined plane connection structure, so that the magnetic flux between the magnetic poles realizes smooth and continuous transition, the total harmonic distortion rate and the torque ripple of the air gap flux density can be effectively reduced, the noise is remarkably improved, and the overall efficiency and stability of the motor are further improved; and in combination with clear parameterization design, rapid optimization can be conveniently carried out in combination with an intelligent algorithm.

The application discloses a transformer adaptive closing method and device, equipment and storage medium, and relates to the technical field of transformer control. The method comprises the following steps: obtaining a winding transient voltage signal in a tripping process of a target transformer, performing numerical integration on the winding transient voltage signal, and obtaining an initial residual magnetism value of the target transformer; obtaining a core leakage flux signal of the target transformer, performing complementary calibration on the initial residual magnetism value based on the core leakage flux signal, and obtaining a dynamic residual magnetism value of the target transformer; determining a target closing time based on the dynamic residual magnetism value of the target transformer, the type of the target transformer and the type of a circuit breaker corresponding to the target transformer; and controlling the circuit breaker to close the target transformer at the target closing time. Through the above method, accurate dynamic measurement of residual magnetism is realized, the ideal closing time with the minimum core residual magnetism and post-closing magnetic flux deviation is adaptively determined according to different transformer types and circuit breaker characteristics, and the magnetic field current surge is effectively inhibited.

The present application provides a magnetic layer having a coercive force Hc of 2.00 kOe or more and a residual magnetization Mrt per unit area of 2.00 memu / cm2 or more, which is achieved without using a non-magnetic underlayer for promoting in-plane orientation of the magnetic layer and without performing heat deposition 2 The above in-plane magnetization film, in-plane magnetization film multilayer structure, hard bias layer, magnetoresistance effect element, and sputtering target. The in-plane magnetization film has: a preliminary magnetic layer (12A) containing Co, Pt, and a non-magnetic grain boundary material and having a thickness of 1 to 32 nm; and a magnetic layer main portion (12B) formed on the preliminary magnetic layer (12A) and containing Co, Pt, and a non-magnetic oxide, the above non-magnetic grain boundary material of the preliminary magnetic layer (12A) containing at least one of a Zn oxide and a Ta oxide.

The application belongs to the technical field of power equipment, and discloses a converter transformer residual magnetism detection sensor and a preparation method thereof; wherein the converter transformer residual magnetism detection sensor comprises a shell, a pressure sensor and an adsorption block; the pressure sensor and the adsorption block are both encapsulated in the shell; the shell is made of non-ferromagnetic material, and the adsorption block is made of ferromagnetic material; the pressure sensor is a flexible pressure sensor, which comprises a dielectric layer and electrode layers arranged on both sides of the dielectric layer respectively; the converter transformer residual magnetism detection sensor is used for being installed on a transformer oil tank; the pressure sensor is located between the core of the converter transformer and the adsorption block; the adsorption block is used for compressing the pressure sensor under the action of residual magnetism in the core; and the pressure sensor is used for outputting a pressure value signal under the compression of the adsorption block. The technical scheme disclosed by the application can be used for detecting the residual magnetism of the converter transformer, and has high residual magnetism detection precision and accuracy.

The invention discloses an air-magnetic overhanging type micro-low gravity test air-floating workbench capable of inhibiting residual magnetism and eddy current interference. The air-magnetic overhanging type micro-low gravity test air-floating workbench comprises a rigid bearing framework and a functional composite material layer. The rigid bearing framework is made of non-magnetic high-specific-stiffness aluminum alloy, and mechanical supporting and magnetic field isolation are achieved. And the functional composite material layer is compounded by uniformly dispersing and consolidating corrosion-resistant nickel-based soft magnetic particles in a non-magnetic matrix, and is used as a gas-magnetic coupling working interface. The adopted nickel-based soft magnetic particles have high saturation flux density, low coercive force, high resistivity and good chemical stability, it is ensured that the functional composite material layer formed by the nickel-based soft magnetic particles has lasting and reliable working surface performance, and residual magnetism interference force and eddy current damping force are fundamentally eliminated on the premise that needed vertical adsorption force is maintained. According to the design, the unexpected horizontal disturbing force generated by the air floatation working table is reduced to one thousandth of the rated vertical bearing force of the gas magnetic bearing, and the precision of dynamic simulation in a micro-low gravity ground experiment is remarkably improved.

The invention relates to a metal magnetic memory stress detection method and device based on strong magnetization enhancement, and belongs to the technical field of metal component stress detection. According to the invention, the permanent magnet is adopted to carry out strong magnetizing pretreatment on the metal component, so that the residual magnetism signal reference is enhanced. On the basis, the integrated automatic detection device integrates magnetizing, multi-channel magnetic signal acquisition and data processing functions, efficient and automatic stress detection is realized, residual magnetism data of discrete points can be converted into a visual stress distribution cloud picture, and high-sensitivity and high-reliability positioning and evaluation of a stress concentration area are realized. The method can improve the precision and sensitivity of stress detection of the metal component, and is suitable for rapid inspection and health monitoring of a large-scale engineering structure.

This invention discloses a neodymium iron boron (NdFeB) magnet, its preparation method, and its applications. The NdFeB magnet of this invention includes a first easily demagnetized region, a first transition region, a non-easily demagnetized region, a second transition region, and a second easily demagnetized region, sequentially distributed along a direction perpendicular to the orientation. All three regions—the first easily demagnetized region, the second easily demagnetized region, the non-easily demagnetized region, the first transition region, and the second transition region—are rectangular. By controlling the Tb content introduced by diffusion in the transition region, the easily demagnetized region, and the non-easily demagnetized region, as well as the Dy content in all regions, this invention can reduce inter-regional Tb diffusion caused by the Tb concentration gradient difference in the transition region. This reduces the attenuation of the surface magnetism and magnetic flux of the NdFeB magnet while maintaining its remanence, thereby improving the demagnetization resistance of the NdFeB magnet. Furthermore, by setting the easily demagnetized region, the non-easily demagnetized region, and the transition region to be rectangular, this invention can improve the demagnetization resistance of the four corners and the long side of the NdFeB magnet.

This invention discloses a cross-axis synchronous in-situ magnetic compensation method for a dual-beam SERF atomic magnetometer, belonging to the field of magnetic compensation technology. Based on the steady-state solution of the Bloch equation, a mathematical correlation is established between the light intensity signal and the triaxial magnetic field. First, the optimization target is determined according to the remanent magnetization direction of the sensitive axis. A three-part nested method is used to iteratively compensate the pump axis remanent magnetization, compensating the pump axis magnetic field to within the error range. Then, in the two-dimensional search space formed by the detection axis and the sensitive axis, the optimal compensation values ​​for the detection axis and the sensitive axis are simultaneously optimized through independent iteration and information interaction using a dual particle swarm optimization algorithm. Finally, the triaxial compensation current value is output to drive the compensation coil to generate a compensation magnetic field, completing rapid and high-precision automatic compensation of the triaxial remanent magnetization. This invention features a simple compensation process, fast convergence speed, and high compensation accuracy, adapting to the application requirements of miniaturized and integrated dual-beam SERF atomic magnetometers, and has significant application value in weak magnetic field detection fields such as biomagnetic imaging.

This application provides a method, system, and closed-loop current sensor residual magnetism calibration method, comprising: providing a closed-loop current sensor; establishing an initial offset value model to fit the B-H curve of the magnetic core of the closed-loop current sensor based on the B-H curve of the magnetic core; turning on the closed-loop current sensor and performing current measurement after initialization, recording the current measurement value, and obtaining the offset value of the corresponding current as the initial offset value during the operation of the closed-loop current sensor based on the initial offset value model; and dynamically calibrating the offset value of the closed-loop current sensor, wherein the dynamic calibration includes: recording the measured current value of the closed-loop current sensor as a new offset value when the measured current crosses zero from positive to negative or from negative to positive; or recording the measured current value of the closed-loop current sensor as a new offset value when the measured current is less than a first set value.

This invention relates to the field of geophysical exploration, specifically disclosing a method for identifying geological body boundaries based on adaptive matching of multi-source gravity and magnetic data. The method includes: acquiring gravity and magnetic anomaly data; estimating the equivalent source depth; constructing a depth-response mismatch correction field based on the depth attenuation difference between gravity and magnetic potential fields; compensating for and registering the magnetic anomaly with remanent magnetization and demagnetization offset; constructing an adaptive coupling direction tensor based on the consistency of the local gradient structures of the two fields; performing anisotropic boundary enhancement on the two fields using the principal direction of the adaptive coupling direction tensor as a constraint and the coupling strength as a weight; and iteratively fusing the two fields through mutual verification using the adaptive coupling direction tensor as a constraint and the depth-response mismatch correction field as a weight, outputting the fine spatial location of the geological body boundary and an adaptive confidence evaluation result. This invention achieves adaptive registration and direction constraint enhancement in the depth domain of gravity and magnetic data, effectively improving the accuracy and reliability of geological body boundary identification under complex geological conditions.

The application relates to the technical field of magnets, in particular to a cerium-doped high-coercivity neodymium-iron-boron magnet and a preparation process thereof. In view of the problem that the existing cerium-doped magnet has insufficient coercivity and reduced remanence due to uneven distribution of cerium, the process comprises the following steps: fluorination treatment on the surface of a main phase powder, cold pressure forming in a magnetic field, electrophoretic deposition to build a cerium fluoride skeleton, step-by-step vacuum impregnation of cerium salt and a fluorine source, and degreasing, sintering and grain boundary heat treatment. The method controls the uniform enrichment of cerium at the grain boundary, forms a continuous and dense grain boundary phase, effectively improves the intrinsic coercivity, remanence and high-temperature stability, simultaneously improves the corrosion resistance and reduces the dependence on heavy rare earths.

The application provides a compressed air energy storage power station main transformer inrush current suppression method and device based on pre-magnetizing phase selection closing technology, and the method comprises the following steps: solving a three-phase five-column transformer magnetic circuit model based on a simplified magnetic hysteresis loop model and considering residual magnetism uncertainty, obtaining pre-magnetizing current size and each phase optimal voltage closing phase, adopting a capacitor as a pre-magnetizing device of the compressed air energy storage power station main transformer pre-magnetizing and phase selection closing device, and designing related device parameters. The application also discloses a corresponding setting system, a computer readable storage medium and a terminal. Through the application, the problem of adjacent element zero sequence overcurrent protection misoperation during transformer air drop can be effectively solved without obtaining any electrical parameters of the transformer and adjacent elements, and meanwhile, the application has the characteristics of simplicity and reliability, easy operation and strong applicability.

The invention provides a method for preparing a samarium-cobalt permanent magnet material based on pre-aging treatment, and relates to the technical field of samarium-cobalt permanent magnet materials. The invention discloses a method for preparing a samarium cobalt permanent magnet material based on pre-aging treatment. The method comprises the steps of precursor preparation, solution treatment, pre-aging treatment, rapid cooling, main aging treatment and the like. Through pre-aging treatment, segregation of solute atoms is promoted at low temperature, high-concentration point defects are formed, uniform and high-density nucleation sites are provided for main aging Sm (Co, Cu) 5 cell wall phase precipitation, precipitation kinetics is accelerated, a nano cellular structure is refined, fine regulation and control of a microstructure are achieved, and the mechanical properties of the Sm (Co, Cu) 5 are improved. The intrinsic coercive force of the magnet is remarkably improved, the residual magnetism and the maximum magnetic energy product of the magnet are synergistically improved, and the prepared samarium-cobalt permanent magnet material is higher in cell wall density, more uniform in distribution and more excellent in comprehensive magnetic performance.

The invention relates to a method for improving fluidity of magnetic powder and preparing a high-consistency magnet, belongs to the technical field of rare earth permanent magnet material preparation, and solves the problem of low performance and density consistency of a sintered neodymium-iron-boron magnet caused by poor fluidity of the magnetic powder, non-uniform pressing density and sintering deformation in the prior art. The method comprises the following steps: optimizing a jet milling process and controlling the granularity of magnetic powder to be 2.4-3.0 microns; the preparation method comprises the following steps of: mixing powder in a mixer filled with inert shielding gas and loaded with hard magnetic grinding particles by adopting a composite additive which is divided twice and has the total amount of 0.18-0.22% and the ratio of (1.5-2): 1 so as to improve the flowability and morphology consistency of the magnetic powder; orientation pressing with the magnetic field not smaller than 2T is adopted, variable-speed segmented pressing and pressure maintaining are executed, and the density of the green body reaches 4.0-4.4 g / cm < 3 >; and finally, through auxiliary low-temperature sintering and two-stage tempering treatment, the heating / cooling rate is controlled not to exceed 4 DEG C / min. The high-uniformity sintered neodymium-iron-boron magnet with the residual magnetism Br consistency superior to 0.4% and the density consistency superior to 0.2% is prepared, and the method is suitable for batch production of high-end equipment.

The invention discloses a neodymium iron boron permanent magnet material and a preparation method and application thereof, and belongs to the field of magnets. The preparation method of the neodymium-iron-boron permanent magnet material comprises the following steps: S1, performing primary film coating on a neodymium-iron-boron diffusion substrate by adopting a first diffusion source to obtain a first precursor; s2, performing secondary film coating on the first precursor by adopting a second diffusion source to obtain a second precursor; and S3, performing diffusion treatment and aging treatment on the second precursor to prepare the neodymium iron boron permanent magnet material, wherein in the steps S1 and S2, the first diffusion source and the second diffusion source respectively and independently comprise heavy rare earth elements; the heavy rare earth element comprises Dy and / or Tb and exists in the form of a heavy rare earth simple substance, a heavy rare earth alloy or a heavy rare earth compound. The obtained permanent magnet material can simultaneously realize excellent performances such as high coercive force, high residual magnetism, high squareness and high diffusion depth; and the preparation method can remarkably shorten the production cycle and reduce the cost, and is especially suitable for large-thickness products.

The application relates to a residual residual magnetism detection method and a detection device, and belongs to an automatic detection method and equipment. The residual residual magnetism detection method comprises the following steps: placing a detection sample on a conveying mechanism, conveying the detection sample to a detection mechanism through the conveying mechanism; under a zero magnetic environment, the detection mechanism detects the residual residual magnetization of the detection sample; after the detection is completed, the detection sample moves to a belt of a sorting mechanism; and according to the detection result of the detection mechanism, the detection sample is classified through the sorting mechanism. The detection method can detect the residual residual magnetization of parts in a production process and / or after processing is completed, can timely monitor and sort, and is high in detection efficiency and accuracy.

This invention relates to the field of molding press technology, and more particularly to a pulsed magnetic field molding press and molding method. The equipment includes a pulsed electromagnet, molding components, and a pulse control circuit, etc. A high-intensity pulsed magnetic field is generated by capacitor discharge to achieve rapid orientation of magnetic powder. Compared with traditional DC magnetic field molding, this invention can significantly shorten the charging and demagnetizing time and improve pressing efficiency. The mold uses a combination of magnetic and non-magnetic materials to optimize the magnetic field distribution. Demagnetization is achieved through reverse pulses, avoiding the influence of residual magnetism. This invention is suitable for one-time molding of magnets with a single unit weight ≤300g, simplifying the process and improving production efficiency and product quality.