453 results about "Magnetism" patented technology

The invention discloses a neodymium-iron-boron magnet, which comprises main phase crystal grains, a thin layer crystal boundary phase and a triangular region crystal boundary phase, and is characterized in that the neodymium-iron-boron magnet comprises 28 to 33 weight percent of R, 0.84 to 0.94 weight percent of B, 0.05 to 1 weight percent of Co, 0.05 to 0.55 weight percent of Cu, 0.3 to 0.6 weight percent of Ga, 0 to 0.55 weight percent of M2, 0.1 to 0.6 weight percent of M3, 66 to 70 weight percent of Fe and the balance of Fe, wherein R is a rare earth element and at least comprises PrNd; the triangular region grain boundary phase comprises an R6T13M1 phase, the element M in the R6T13M1 phase is selected from any two or more elements of Al, Cu, Ga, Ti, Sn and / or Zr, and the element T comprises Fe and / or Co; the sum of the areas of the R6T13M1 phases in the microscopic structure cross section of the neodymium-iron-boron magnet accounts for 5.2%-8.4% of the area of the microscopic structure cross section. The rare earth permanent magnet with high residual magnetism, high coercive force and good squareness consistency is obtained under the condition that no heavy rare earth is added or a small amount of heavy rare earth is added.

The invention belongs to the technical field of geophysics, and particularly discloses a magnetization intensity vector sparse inversion method under a strong residual magnetism condition. The method comprises the following steps: firstly, subdividing an underground space, and simulating an underground magnetic anomalous body; obtaining a sensitivity matrix according to partial derivatives of observed magnetic anomaly values of the magnetic anomaly body in each unit magnetization direction, and constructing a total objective function of magnetization intensity vector inversion based on the sensitivity matrix; taking magnetization intensity amplitude as a parameter to introduce sparse constraint for the total objective function; converting the total target function into a standard L2 regularization form, and calculating a sensitivity matrix by using a singular value analysis method so as to obtain target parameters of the total target function; and finally, obtaining three components of the magnetization intensity vector from the target parameters, and further solving the magnetization intensity amplitude and the total magnetization direction. According to the scheme, the magnetization intensity inversion precision under the influence of strong residual magnetization is effectively improved.

The invention relates to the technical field of magnetic materials, in particular to a grain boundary diffusion method of a neodymium-iron-boron rare earth permanent magnet material, which comprises the following steps: preparing a sintered neodymium-iron-boron diffusion matrix, a diffusion source being turbid liquid slurry consisting of a mixture of rare earth fluoride and rare earth oxide and a proper amount of organic solvent; the method comprises the following steps: processing a diffusion substrate into a required size, carrying out grain boundary diffusion treatment after oil removal and acid pickling treatment, coating the surface of the diffusion substrate with a diffusion source, drying the coated magnet, carrying out primary diffusion treatment, and carrying out secondary low-temperature tempering treatment. The diffusion method provided by the invention is simple in process, can effectively improve the coercive force of the neodymium-iron-boron magnet, especially the coercive force of a Ce-containing magnet, and is embodied in the following aspects: improving the anisotropic field of the surface of a crystal grain, improving the microstructure of a crystal boundary, effectively increasing the diffusion depth, obviously improving the coercive force of the magnet, and improving the coercive force of the neodymium-iron-boron magnet. And the original residual magnetism and the maximum magnetic energy product of the magnet are not obviously reduced.

The invention discloses a reweighted inversion method and system for a magnetic anomaly modulus under a residual magnetism condition and a storage medium, and belongs to the technical field of magnetic exploration, and the method comprises the following steps: converting the magnetic anomaly modulus to obtain the magnetic anomaly modulus; carrying out nonlinear forward modeling on the magnetic anomaly modulus; and linearizing a forward modeling formula of the magnetic anomaly modulus, constructing a reweighted minimum model objective function, solving the reweighted minimum model objective function, finally obtaining the magnetization intensity of an inversion space, and delineating a target geologic body. According to the scheme, the nonlinear forward modeling formula of the magnetic anomaly modulus is subjected to linear representation, and the sensitivity matrix serving as depth weighting is further updated by utilizing the magnetic anomaly modulus kernel function matrix updated along with iteration, so that the reweighting minimum model objective function is constructed, the precision of magnetic anomaly modulus inversion under the residual magnetism condition is improved, and the accuracy of the magnetic anomaly modulus inversion under the residual magnetism condition is improved. And a more reliable inversion result is provided for more accurate depiction of a deep magnetic structure, mineral resource exploration and the like.

The invention relates to the technical field of neodymium-iron-boron magnets, in particular to a neodymium-iron-boron rare earth magnet and a preparation method thereof.The neodymium-iron-boron rare earth magnet is a sintered neodymium-iron-boron permanent magnet and comprises a main phase, a two-particle grain boundary phase and a triangular area grain boundary phase; the main phase comprises an R2T14B phase, R refers to at least one of Nd and Pr, T refers to Fe, and Co at least contains Fe; the two-particle grain boundary phase comprises a grain boundary copper-rich phase, and / or a needle-shaped ZrBx phase with the width of 10-50 nm, and / or a needle-shaped TiBx phase with the width of 10-50 nm; the triangular region grain boundary phase comprises an FCC type NdOx phase, an RCu phase, an RGa phase, an R-rich phase, a 6: 14 phase and / or a needle-shaped ZrBx phase with the width of 10-50 nm and / or a needle-shaped TiBx phase with the width of 10-50 nm, the neodymium-iron-boron rare earth magnet does not contain heavy rare earth and is good in uniformity, and the coercive force and residual magnetism can be regulated and controlled through the design of the grain boundary phase.

The invention provides a method for preparing a high-coercivity sintered neodymium-iron-boron magnet, and belongs to the technical field of rare earth permanent magnet material preparation, and the method comprises the following steps: 1, taking the sintered neodymium-iron-boron magnet as a base material, and removing an oxide layer through alkali washing deoiling, ultrasonic water washing and acid pickling cleaning; 2, taking the Pr-Dy-Cu-Ga quaternary alloy as a diffusion source, and cutting the Pr-Dy-Cu-Ga quaternary alloy into slices; 3, attaching the thin sheet to the surface of a base material for diffusion heat treatment; fourthly, low-temperature tempering is conducted; 5, testing a room temperature demagnetization curve of the sample; light rare earth Pr replaces a part of heavy rare earth Dy and is matched with Cu and Ga elements in a certain proportion to be smelted to obtain quaternary alloy, the quaternary alloy with low heavy rare earth serves as a diffusion source, the microscopic characteristics of the magnet are improved, grain boundary phase distribution is optimized, and under the condition that residual magnetism and the maximum magnetic energy product are slightly reduced, the coercive force of the sintered neodymium-iron-boron magnet is improved; and terbium and dysprosium are not used, so that the use amount of heavy rare earth elements and the production cost are reduced.

The present invention discloses a demagnetization method based on a weak magnetic environment. A three-axis geomagnetic compensation coil is built outside a passive shielding device. Current is injected into the coil to generate a reverse magnetic field to offset the geomagnetism, thereby providing a weak magnetic environment for the shielding device. Based on the weak magnetic environment, a demagnetization power supply control system and a demagnetization coil are used to demagnetize the passive shielding layer of the magnetic shielding device, thereby further improving the demagnetization performance. This method can not only reduce the cost of using high-performance shielding materials when the magnetic shielding device adopts multi-layer shielding, but also effectively reduce the residual magnetism inside the shielding space, thereby constructing an extremely weak magnetic environment.

The invention discloses a ferromagnetic cavity physical and magnetic coupling modeling method, and relates to the technical field of electromagnetic property analysis, the method adopts a COMSOL Multiphysics finite element simulation technology, and combines hysteresis loop measurement of a ferromagnetic material, a Jiles-Atherton parameter recognition algorithm, a tensile test, residual magnetism measurement and a force and magnetic coupling test, so that the ferromagnetic cavity physical and magnetic coupling modeling method is realized. According to the method, the magnetization behaviors of the ferromagnetic cavity under the action of different stresses and magnetic fields are accurately simulated, the high-precision force-magnetic coupling simulation model is established by automatically identifying five Jiles-Atherton parameters of the ferromagnetic material and combining mechanics and residual magnetism data, space magnetic field distribution under the specified working condition is rapidly calculated, and the method has the advantages of being high in modeling efficiency and high in calculation precision.

The invention relates to the technical field of magnetic separation, in particular to a magnetic gradient separation fire metal material evidence screening machine and a multistage magnetic field regulation and control method thereof.The magnetic gradient separation fire metal material evidence screening machine comprises a machine body, a feeding pipe and rotating cylinders are rotationally connected to an inner cavity of the machine body, magnetic separation assemblies are installed between the feeding pipe and the rotating cylinders and between the two rotating cylinders, and driven gears are installed on the outer walls of the feeding pipe and the rotating cylinders; according to the multi-stage magnetic separation device, the multi-stage magnetic separation design is adopted, magnetic force sequentially increased from top to bottom of the magnetic separation assembly is combined with centrifugal force generated by rotation of the feeding pipe and the rotating cylinders, and materials are evenly dispersed and make full contact with the magnetic separation assembly; meanwhile, the valve plate assemblies are sequentially opened in the descending process of the abutting blocks, so that the materials sequentially fall down layer by layer, sorting disorder caused by falling of a large number of materials at a time is avoided, the materials can be kept for enough time on each magnetic separation assembly, it is ensured that metal material evidences with different magnetisms are fully adsorbed, and the screening accuracy is greatly improved.

The utility model relates to the technical field of magnetron sputtering, and particularly discloses a high-sputtering-rate magnetron sputtering target gun which comprises a target seat, an anode cover body arranged on the outer side of the target seat, a target material body mounted in a mounting groove, a copper back plate arranged on the upper side of the bottom end of the target seat, and a target material gland arranged on the outer side of the bottom end of the target seat, a magnetic ring is further arranged between the first cooling copper table and the second cooling copper table, a magnetic yoke is installed at the upper end of the second cooling copper table, a connecting aluminum table is installed at the upper end of the magnetic yoke, and an insulator is arranged on the outer side of the connecting aluminum table. According to the utility model, the spatial position of the permanent magnet magnetic steel and the structure of the target gun are optimized, so that the magnetic intensity penetrating through the surface of a target material is guaranteed, the magnetic field intensity of a magnetic control plasma area is high, the magnetic control effect is more obvious, the sputtering rate of magnetron sputtering is greatly improved, the production efficiency of magnetron sputtering is also improved, and the production cost is reduced. And for a magnetic material which cannot be sputtered by common magnetron sputtering, sputtering deposition can also be carried out, so that the application range of magnetron sputtering is wider.

The invention discloses a nanocrystal magnetic material and a preparation method thereof, the nanocrystal magnetic material is a magnetic Nb3VSe6 crystal and comprises three elements, namely Nb, V and Se, the metered molar ratio of the three elements is 3: 1: 6, the crystal has a centrosymmetric broken hexagonal layered structure, the space group of the crystal is P6322, V atoms are inserted between two 2H-NbS2 hexagonal layers, the lattice constants a = b = 5.738, and c = 12.018. The magnetism in the material is mainly contributed by positive trivalent Cr ions, the magnetic moment is 3B, the local electron spin S is equal to 3 / 2, and conduction electrons are from unfilled bands of Nb atoms. Due to the unique crystal structure and electronic property, the material shows potential application value in multiple fields, especially in the aspects of high-frequency devices, spintronics elements, magnetic dampers and the like. The Nb3VSe6 single crystal is relatively stable in air, which is a great advantage for practical application.

The present invention relates to the technical field of powder metallurgy, and in particular to a sintered NdFeB and a preparation method thereof, wherein the heat treatment temperature and time are adjusted to promote the RE6Fe 13 The M phase is generated or disappears, thereby increasing or decreasing the remanence and coercivity of the magnet; specifically, by composition design or adding RE6Fe to the grain boundary 13 The M phase alloy composition is then adjusted to 420‑700°C heat treatment temperature to promote RE6Fe 13 The M phase is formed or disappears. This method can regulate the changes in remanence and coercivity within a certain range to improve the redundancy of the formulation process, and at the same time can better adapt to the different performance requirements of customers, with excellent economic benefits.

The invention discloses a method for simultaneously optimizing the squareness and the remanence temperature coefficient of a 2: 17 type samarium-cobalt sintered magnet, and belongs to the technical field of rare earth permanent magnet material preparation. A component Sm < 1-x > RE < x > (CobalFeaCubZrc) z is designed, RE is one or more of Dy, Er, Gd, Tm and other heavy rare earth elements, and a, b, c and x meet the following relations: 0 < = x < = 0.6, 0.1 < = a < = 0.2, 0.06 < = b < = 0.12, 0.02 < = c < = 0.03, and 6.9 < = z < = 7.9. On the basis of a conventional smelting and ingot casting-isothermal annealing-powder preparation-oriented profiling-sintering-solid solution-aging process, an isothermal annealing process is added after smelting and ingot casting: the temperature is raised to 1190-1210 DEG C in a tubular furnace, isothermal annealing is performed for 5-20 hours, heavy rare earth elements are eliminated, and the influence of the stability of a 2: 17H phase on the component uniformity and magnetic performance of a magnet is improved; and substitution sites of heavy rare earth can be increased, and the residual magnetism temperature coefficient is optimized.

The present invention provides a flywheel energy storage flux adjustable induction motor and its magnetic adjustment method, wherein the motor comprises two permanent magnets with different coercive forces and a DC magnetic adjustment winding. A square wave pulse is input into the DC magnetic adjustment winding to generate a magnetic adjustment magnetic field, so that the residual magnetism of the low-coercive force permanent magnet changes in magnitude or direction, thereby realizing rapid adjustment of the motor air gap flux. When the motor is working, the DC magnetic adjustment winding is disconnected, and the residual magnetic flux generated by the high-coercive force permanent magnet and the low-coercive force permanent magnet enters the air gap in parallel to provide excitation flux for the motor; when the motor is on standby, a negative square wave pulse is input into the DC magnetic adjustment winding to generate a magnetic adjustment magnetic field that can reversely saturate magnetize the low-coercive force permanent magnet, so that the low-coercive force permanent magnet is reversely magnetized, and the residual magnetic flux of the high-coercive force and low-coercive force permanent magnets is equal in magnitude and opposite in direction, so that the air gap flux is reduced to 0, thereby eliminating standby iron loss. In addition, the DC magnetic adjustment winding can also be used as a backup excitation source to prevent the risk of permanent magnet demagnetization.

The invention relates to a method for dynamically eliminating residual magnetism of an iron core of a converter transformer, and belongs to the field of transformer demagnetization. According to the method, a capacitance energy storage and release device is connected to the two ends of a transformer winding, capacitance energy storage causes RLC oscillation of the transformer, a magnetic field is generated through current caused by the RLC oscillation, and magnetic domains of iron core ferromagnetic materials are rearranged through the changed magnetic field, so that the demagnetization effect on residual magnetism of the transformer is achieved. The method comprises the following steps: drawing a hysteresis loop in the demagnetization process of a transformer by collecting voltage and current data in the demagnetization process, translating an end point of the hysteresis loop to an original point, and judging the residual magnetism direction and size of initial demagnetization according to the area of each quadrant of the hysteresis loop; and then transformer demagnetization is carried out again, the residual magnetism direction and size of the first demagnetization are evaluated according to the hysteresis loop of the second demagnetization, and whether the residual magnetism is smaller than a threshold value is judged. According to the method, the direction and size of residual magnetism in the demagnetization process can be evaluated in real time, the demagnetization energy is dynamically adjusted, and sufficient demagnetization of the converter transformer is ensured.

A treatment method for enhancing coercive force of neodymium iron boron magnet includes the following steps: subjecting the neodymium iron boron magnet to electrochemical deposition in a diffusion water-based solution to obtain a neodymium iron boron magnet containing a heavy rare earth; and subjecting the neodymium iron boron magnet containing the heavy rare earth to heat treatment to complete enhancement of the coercive force of the neodymium iron boron magnet. The raw material used in the present invention is cheap heavy rare earth compounds which increases the selection of diffusion sources and lowers costs. Metal alloy particles are mainly obtained in a nanoscale size and can effectively enter crystal grains, and low-melting-point metal alloy components can enhance a demagnetizing coupling effect between main phase grains. According to the present invention, the coercive force of the magnet is increased by nearly 30%, and residual magnetism is almost not changed.

The invention discloses a high-performance ultrathin rare earth permanent magnet sheet and a preparation method thereof, and belongs to the technical field of rare earth permanent magnet material preparation. The preparation method comprises the following steps: melting an iron raw material and a part of a samarium raw material under a vacuum condition, then adding the balance of samarium, continuously melting, and pouring the obtained molten alloy onto a cooling roller to obtain a samarium-iron alloy sheet; the samarium-iron alloy sheet is sequentially subjected to homogenization treatment, hydrotreating and nitriding treatment, and nitrided magnetic powder is obtained; adding phosphoric acid and a corrosion inhibitor into the magnetic powder, carrying out wet ball milling, and drying to obtain surface-treated magnetic powder; adding a binder into the surface-treated magnetic powder, and banburying to obtain magnetic particles; the magnetic particles are pressed by a press vulcanizer, the thickness of the prepared rare earth permanent magnetic sheet is only 0.2 mm-0. 4mm, and the magnetic sheet is high in corrosion resistance, sufficient in surface magnetism, high in magnetic performance, low in preparation cost and capable of meeting application requirements of specific scenes.

The invention belongs to the field of magnetic particle imaging, particularly relates to a zero-inertia magnetism gathering ring magnetic-field-free line magnetic particle imaging system and method, and aims to solve the problems of low magnetic field gradient, high magnetic field control complexity and limited imaging space. The current of a gradient magnetic field coil group is generated by a magnetic field control and imaging module, is output by a signal acquisition and output module, and is amplified and provided by a gradient power amplifier module. The current of the axial excitation magnetic field coil is generated by the magnetic field control and imaging module, is output by the signal acquisition and output module and is amplified and provided by the excitation power amplifier module, and a signal received by the multi-axis detection coil is filtered and amplified by the signal processing unit and then is input to the imaging module by the magnetic field control and imaging module for algorithm reconstruction. According to the invention, the magnetic field gradient and the control precision are obviously improved, and the imaging space of the axial fault plane is realized.

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 relates to the field of electromagnetism, in particular to a micro-magnetic method for predicting magnetic characteristics of a magnetic sample, which comprises the following steps of: (1) constructing a plurality of magnet models with different magnetic domain sizes, shapes and magnetic domain numbers, and determining magnetic parameters of the magnet models; (2) placing the to-be-measured magnet under a preset external field condition to obtain the magnetization intensity of the to-be-measured magnet, and comparing the magnetization intensity with the measurement result of each model under the same external field condition; (3) determining the similarity between the to-be-tested magnet and each model, finding out the model with the highest similarity, and calling each magnetic parameter of the model; and (4) determining the external field condition of the magnet to be detected in the new target environment.

The invention relates to the technical field of magnetic force detection, and provides a microelectronic magnetic force detection device which comprises magnetic cores, a feeding track, a feeding assembly, magnetic core butt joint mechanisms, a conveying frame, a conveying mechanism and a magnetic detection mechanism, the multiple magnetic cores are arranged on the feeding track in a sliding mode, the feeding assembly is used for conveying the magnetic cores to move, and the two magnetic core butt joint mechanisms are oppositely arranged; the magnetic core butt joint mechanism is fixedly arranged on the sides, away from the feeding assembly, of the feeding rails, the magnetic core butt joint mechanism is used for driving magnetic cores to turn over and be in butt joint, the conveying mechanism is used for conveying the magnetic cores on the feeding rails to the magnetic core butt joint mechanism, and the magnetism detection mechanism is arranged between the two feeding rails; by means of the technical scheme, the problem that in the prior art, when the magnetic cores in a transformer are detected, it is difficult to conduct magnetic detection on a large number of special-shaped and multi-model magnetic cores is solved.

The invention discloses a hybrid excitation electric roller direct drive motor, and relates to the technical field of motors, the hybrid excitation electric roller direct drive motor comprises a shell, a shaft is rotatably connected to the center of the shell, and a stator iron core is rotatably connected to the outer wall of the shaft. On one hand, the magnetic resistance torque is fully utilized and the use amount of the permanent magnet is reduced by utilizing the characteristics of the magnetism-assisting synchronous magnetic resistance structure, and on the other hand, ferrite without rare earth and neodymium iron boron containing rare earth are mixed for use by adopting a magnetic mixing technology, so that the use amount of the rare earth permanent magnet can be further reduced, and the use amount of the rare earth permanent magnet can be reduced by about half under the same performance index; and secondly, through reasonable arrangement of the permanent magnets and adjustment of the distribution of the magnetic field, the magnetic circuit design is more optimized, the magnetic field is accurately controlled, and the demagnetization resistance of the ferrite in a reverse magnetic field can be improved.

The invention relates to the technical field of rare earth permanent magnet materials, in particular to a corrosion-resistant grain boundary diffusion neodymium-iron-boron magnet and a preparation method thereof.The preparation method comprises the steps that a sintered neodymium-iron-boron blank is obtained, a diffusion source is obtained, a grain boundary diffusant is modulated, the diffusion source is Zn alpha Li beta Mn 100-alpha-beta alloy according to the mass ratio (wt.%), alpha is larger than or equal to 60 wt.% and larger than or equal to 10 wt.%, the neodymium-iron-boron blank is treated, and the grain boundary diffusant is prepared; and coating the surface of the magnet with a diffusant to obtain a composite magnetic sheet, and carrying out grain boundary diffusion heat treatment on the composite magnetic sheet to obtain the corrosion-resistant grain boundary diffusion neodymium-iron-boron magnet. The diffusion source used in the method is low in price and high in matching degree with traditional equipment, raw materials are not required to be additionally purchased except the diffusion source, the cost performance is high, the corrosion-resistant weight loss ratio can be effectively reduced, the residual magnetism and coercive force of the magnetic performance of the magnet are slightly improved compared with those of a blank magnet, the problem of balancing the corrosion resistance and the magnetic performance is solved, and the service life of the magnet is prolonged. And the obtained corrosion-resistant grain boundary diffusion neodymium-iron-boron magnet is excellent in performance.

The utility model relates to the technical field of nucleic acid extraction, and particularly discloses a magnetic rod stirring sleeve assembly and a nucleic acid extractor. The magnetic rod stirring sleeve assembly comprises a magnetic rod and a magnetic rod base, a plurality of magnetic suction seats with magnetism are arranged on the magnetic bar base; the magnetic bar is connected to the magnetic suction seat in a magnetic suction manner; the magnetic attraction base is used for generating magnetic traction force to the magnetic bar so that the magnetic bar can be perpendicular to the magnetic bar base. According to the scheme, through magnetic attraction cooperation of the magnetic attraction base and the magnetic bar, the magnetic bar can be finely adjusted in the horizontal position so as to adapt to stirring sleeves of different sizes; meanwhile, in the process that the magnetic bar is arranged in the stirring sleeve and in the stirring process of the stirring sleeve, the magnetic attraction base can continuously provide magnetic traction force for the magnetic bar to ensure the perpendicularity of the magnetic bar, the deviation of the magnetic bar and the center position of the stirring sleeve is reduced, and therefore the effect of improving the nucleic acid extraction quality is achieved.

The invention discloses a neodymium-iron-boron magnet, the neodymium-iron-boron magnet comprises R2T14B main phase grains and a grain boundary phase, a heavy rare earth shell layer is arranged on the surface layer of the R2T14B main phase grains in the area, 0.1-100 microns away from the surface of the magnet, of the neodymium-iron-boron magnet, the neodymium-iron-boron magnet comprises the following components: 28-32 wt% of R, 0.85-0.94 wt% of B, 0.4-2 wt% of Co, 0.1-0.8 wt% of Cu, 0.1-0.3 wt% of Ga, 0.05-0.5 wt% of Al and 0.4-1.0 wt% of M1, M1 is selected from one or two of Ti, Zr, Nb, W and V, and 63-69 wt% of Fe; wherein R is a rare earth element and at least comprises PrNd and RH, and RH is a heavy rare earth element and is selected from one or two of Dy and Tb; wherein the area of all grain boundary phases in the cross section of the neodymium-iron-boron magnet, which is 0.1-100 microns away from the surface of the magnet, accounts for 5.2-7.5% of the total area of the cross section.

The invention discloses a screening device for magnetic material processing, and belongs to the technical field of material screening, the screening device comprises a conveying device, the conveying device is used for conveying magnetic materials to be screened, the conveying device is provided with a grinding device and three fine separation devices, the grinding device is used for grinding the magnetic materials, and the fine separation devices are arranged on the conveying device; the fine separation device is used for finely screening the magnetic material; the three fine separation devices can screen the magnetic materials into six different magnetic materials according to the magnetism and the thermal sensitivity of the magnetic materials, and the screening effect is good; magnetic materials are adsorbed through the electromagnets arranged in the rotary drum, the materials with different magnetisms are screened out from different discharging grooves in cooperation with rotation of the rotary drum, and the screening precision is high; the grinding device grinds a magnetic material to a specified size so that the magnetic material can be conveniently adsorbed by an electromagnet, then the ground magnetic material is automatically conveyed through the conveying device, and the magnetic material is conveyed to pass through the three fine separation devices, so that full-automatic fine separation of the magnetic material is realized, the automation degree is high, and the continuity is good.

A magnetic sensor according to the present invention is capable of measuring a small magnetic field with high accuracy by eliminating 1 / f noise. The magnetic sensor comprises a variable magnetic field detection unit that includes a Hall element having a magnetism-sensing direction giving rise to an anomalous Hall effect and a magnetic field control unit for controlling the Hall element so that a magnetic field having a component in a non-sensing direction orthogonal to the magnetism-sensing direction is generated in the Hall element. The magnetic sensor may further comprise a magnetic field calculation unit that calculates a measurement magnetic field on the basis of a first output and a second output, the first output including a measurement result obtained when the variable magnetic field detection unit measures a measurement magnetic field along the magnetism-sensing direction in a first state in which the direction of the magnetic field generated in the Hall element is not controlled by the magnetic field control unit, the second output including a measurement result obtained when the variable magnetic field detection unit measures the measurement magnetic field in a second state in which the direction of the magnetic field generated in the Hall element is controlled by the magnetic field control unit.

The invention discloses a high-remanence cerium-rich mixed rare earth permanent magnet material and a preparation method thereof, and belongs to the field of rare earth permanent magnet materials. The preparation method of the high-remanence cerium-rich mischmetal permanent magnet material comprises the following steps: (1) preparing magnetic powder, and preparing a sintered cerium-rich mischmetal permanent magnet base material magnet through a sintering process; (2) carrying out grain boundary diffusion treatment on the base material magnet by using a diffusant obtained by mixing rare earth hydrogenated powder and metal elementary substance / alloy nano powder in proportion; and (3) carrying out multi-step heat treatment on the diffused magnet to finally obtain the high-remanence cerium-rich mixed rare earth permanent magnet material. By redesigning a base material magnet and a grain boundary diffusion source and innovating a heat treatment process after diffusion, the residual magnetism of the cerium-rich mixed rare earth permanent magnet material is greatly improved, so that the comprehensive magnetic performance is improved, and the industrial application of high-abundance rare earth cerium and mixed rare earth in the rare earth permanent magnet material is promoted.

The invention discloses a residual magnetism detection method and a residual magnetism detection device for a shielding plate, and the method comprises the steps: detecting the actual magnetic field intensity vector value of each preset point location for N preset point locations on the surface of a to-be-detected shielding plate, n is an integer greater than or equal to 2; calculating a difference value between the actual magnetic field intensity vector value and the ideal magnetic field intensity vector value at each preset point location, and taking the difference value as a target magnetic field intensity vector value at the preset point location; the ideal magnetic field intensity vector value is a magnetic field intensity vector value when no residual magnetism and magnetic leakage exist at the preset point position; and judging whether the shielding plate is available or not based on the target magnetic field intensity vector values at the N preset point positions on the surface of the shielding plate. The residual magnetism detection method can detect the residual magnetism or magnetic leakage performance of the shielding plate in a general environment or a low-cost magnetic shielding environment.

The invention relates to the technical field of rare earth permanent magnet materials, in particular to a grain boundary diffusion magnet based on a hard magnetic 6: 14 phase and a preparation method of the grain boundary diffusion magnet. Preparing a diffusion source, and loading the diffusion source on the surface of the matrix magnet; carrying out heat preservation diffusion under the environment pressure of which the vacuum degree is less than or equal to 10 <-2 > Pa; and carrying out aging treatment to obtain the grain boundary diffusion magnet based on the hard magnetic 6: 14 phase. The grain boundary phase of the prepared grain boundary diffusion magnet based on the hard magnetism 6: 14 phase is mainly the continuous 6: 14 phase, the hard magnetism is presented, the coercive force is improved, meanwhile, the residual magnetism is prevented from being reduced, the problems that the coercive force of an existing neodymium-iron-boron magnet is improved in a limited mode, and the residual magnetism cannot be prevented from being reduced are solved, and the service life of the neodymium-iron-boron magnet is prolonged. The invention provides a low-cost high-comprehensive-magnetic-performance grain boundary diffusion magnet preparation method.