19 results about "Demagnetizing field" patented technology

The invention discloses a permanent magnet steel magnetic performance degradation law prediction method based on magnetic viscosity. The invention belongs to the technical field of permanent magnet steel, and particularly relates to a permanent magnet steel magnetic performance degradation law prediction method based on magnetic viscosity. The invention aims to solve the problem that the magnetic performance degradation rule of the magnetic steel cannot be accurately predicted in the prior art. The method comprises the following steps: carrying out a magnetic viscosity performance test on permanent magnet steel based on a vibration sample magnetometer to obtain a time-varying curve of magnetization intensity, a logarithmic relation curve of magnetization intensity and time and a relation curve of a magnetic viscosity coefficient and an external magnetic field; analyzing the influence of the demagnetizing field on the relationship between the total magnetic field and the external magnetic field in the magneto-viscous process, and obtaining the relationship data of the total magnetic field and the external magnetic field; constructing a magnetic performance degradation prediction model, and introducing temperature coefficient correction to obtain a relationship among magnetization intensity variation, storage time, an applied magnetic field, a demagnetization factor and initial magnetization intensity; and predicting the magnetic performance degradation law of the permanent magnet steel through the magnetic performance degradation amount prediction model.

This invention proposes a metal soft magnetic powder core with excellent low-frequency magnetic properties and its preparation method, belonging to the field of magnetic materials. Using at least nano-boron powder and iron-silicon soft magnetic alloy powder as raw materials, high-temperature diffusion and high-temperature nitriding treatments are employed. Part of the nano-boron powder forms a high-resistivity iron-silicon-boron permeation layer on the surface of the iron-silicon soft magnetic alloy powder, while some nano-boron powder forms a boron nitride insulating layer with both high resistivity and high thermal stability between the iron-silicon soft magnetic alloy powders, effectively controlling eddy currents. Hot pressing further increases the density of the metal soft magnetic powder core, reduces the demagnetizing field, thereby improving permeability and reducing hysteresis loss. Thus, excellent low-frequency magnetic properties of high density, high permeability, and low loss are simultaneously obtained in the metal soft magnetic powder core.

The invention relates to the field of magnetic field detection, and discloses a method for integrally detecting a three-dimensional vector magnetic field based on excitation and reading, a spin-orbit torque device sensor is adopted, a ferromagnetic material of the sensor has zero residual magnetism and perpendicular magnetic anisotropy, and the method comprises the following steps: applying excitation current to the sensor, and reading output voltage at the same time; obtaining R-H curves of an independent x-direction magnetic field, an independent y-direction magnetic field and an independent z-direction magnetic field; the sensor is placed in a magnetic field to be measured, information of each component of a magnetic field vector is solved through operation by changing the polarity and direction of pulse current, and the size and direction of an unknown magnetic field are obtained according to three components obtained in three directions. Under the combined action of the spin-orbit torque in the sensor, the anisotropic field of the magnetic layer of the zero-remanence magnet, the demagnetizing field and the applied external magnetic field, the write-in and read operations are completed at the same time under the driving of the pulse current, and the function of rapidly and accurately measuring the three-dimensional magnetic field by a single device can be realized.

The invention discloses a high-performance soft magnetic composite material and a preparation method thereof, and belongs to the technical field of preparation of soft magnetic composites.The preparation method of the high-performance soft magnetic composite material comprises the following steps that filamentous soft magnetic alloy is arranged in parallel and in order in the working magnetic circuit direction (the annular direction), and is filled with insulating media in the non-working magnetic circuit direction (the axial direction and the radial direction); and preparing to obtain the high-performance soft magnetic composite material. The soft magnetic composite material prepared by the preparation method provided by the invention has the following three advantages: (1) magnetic resistance is reduced; and an insulating air gap in the working magnetic circuit direction is eliminated, so that the magnetic resistance is reduced to 1 / 10 of that of a traditional structure, and the magnetic conductivity is greatly improved. And (2) eliminating a demagnetizing field. The axial demagnetization factor N of the filiform structure is equal to 0, and compared with spherical particles (N is equal to 1 / 3), the local demagnetization field is remarkably reduced, so that the magnetic conductivity is improved, and the magnetic hysteresis loss is reduced. And (3) the performance of the material components is utilized to the maximum extent. The induced eddy current is perpendicular to the magnetic circuit, and the size of the induced eddy current is directly related to the resistivity in the direction perpendicular to the magnetic circuit but not related to the resistivity in the magnetic circuit direction.

Disclosed in the embodiments of the present invention is a low-magnetic-field magnetoresistive angle sensor. The sensor comprises: a substrate located in an X-Y plane, and a magnetoresistive sensing unit located on the substrate. The magnetoresistive sensing unit comprising a multi-layer thin film structure. The multi-layer thin film structure comprises at least a stack of a free layer, a barrier layer, and a reference layer. The magnetoresistive sensing unit has an oval shape. The oval-shaped free layer has a long axis Ly, a short axis Lx, and a thickness Lz. Additionally the free layer has a saturation magnetic field, a shape anisotropy demagnetizing field, and a magnetocrystalline anisotropy field in the X direction. When an external magnetic field rotates by 0-360° in the X-Y plane, the magnetocrystalline anisotropy field is compensated by the shape demagnetizing field to cause the effective anisotropy field of the free layer to be close to 0, such that the external magnetic field has a low working magnetic field value close to that of the saturation magnetic field of the free layer material. The embodiments of the present invention can improve the accuracy of angle measurement of a magnetoresistive angle sensor. Additionally because the required external magnetic field is low, the sensor can be implemented at low cost.

The utility model discloses a rotor assembly, a rotor assembly, a motor and electrical equipment, in the rotor assembly, an edge groove is formed between the outer side of a magnetic steel groove and the outer side of a magnetic steel section, and one end of the edge groove is located at the corner of the magnetic steel groove; the length of each side groove is a and the width of each side groove is b, and a / b is larger than or equal to 4, so that the side grooves at the corner positions of the outer sides of the magnetic steel grooves, namely the positions where stress concentration is likely to be generated, form a long shape, and the magnetic resistance of a reverse magnetic field at the corner areas of the magnetic steel is increased to restrain the demagnetization intensity. And the magnetic steel assembly comprises a plurality of magnetic steel sections correspondingly arranged in the magnetic steel grooves, and the plurality of magnetic steel sections are stacked in the axial direction of the rotor core, so that the stability of the magnetic steel sections at a high rotating speed is ensured. Through the improved design of the rotor assembly, rotor magnetic steel demagnetization is reduced, magnetic steel eddy current loss is reduced, and motor operation efficiency is improved.

A neutron polarization reversal device includes: a guide magnet for generating a guide magnetic field within a preset area; a reversal assembly including a reversal bracket, a first coil, and a second coil, wherein the first coil and the second coil are wound around the reversal bracket so as to be positioned within the preset area; a driving device for outputting a current to the first coil after receiving a target shooting control signal from an accelerator, so as to generate a compensation magnetic field opposite to the guide magnetic field, and to form a demagnetizing field region in the intersecting area of ​​the guide magnetic field and the compensation magnetic field; and further for outputting a current to the second coil, so as to generate a precession magnetic field orthogonal to the guide magnetic field and the compensation magnetic field in the demagnetizing field region. Neutron polarization reversal is achieved based on the Larmor precession of neutrons, making the neutron polarization reversal device simple in structure, easy to implement, and fast in reversal speed. Furthermore, the device can receive a target shooting control signal from an accelerator and perform neutron reversal in accordance with the target shooting control signal. The present invention also provides a neutron polarization reversal device.

A Ku-band self-biased circulator belongs to the field of microwave ferrite device technology. The circulator includes a composite substrate and a microstrip circuit formed on the composite substrate; wherein the composite substrate includes a secondary dielectric sheet and an array of ferrite rods nested within the secondary dielectric sheet, the array of ferrite rods being composed of nested array of ferrite rods and a primary dielectric substrate. This invention, by employing a composite substrate structure with array of ferrite rods nested within a primary dielectric substrate, effectively reduces the influence of demagnetizing fields through the placement of the rod-shaped ferrites. The synergistic generation of multiple rod-shaped ferrites produces a stable bias magnetic field, providing good control over the device's operating frequency range. While maintaining non-reciprocal characteristics, it significantly reduces magnetic loss in the Ku-band, thereby reducing insertion loss.

A permanent magnet synchronous servo motor rotor structure belongs to the technical field of motors. Comprising a rotor shaft, a rotor core and a plurality of permanent magnets. The rotor shaft is arranged at the center of the rotor iron core; and the permanent magnet is rotationally arranged on the outer ring of the rotor shaft through the embedding hole. According to the rotor iron core, a plurality of iron cores are not separated and are of an integral structure, so that magnetic resistance can be reduced, and the assembling efficiency can be improved while leakage magnetic flux is blocked; the permanent magnets are arranged in the embedding holes, so that the permanent magnets are not exposed to an external demagnetizing field, the magnetic flux leakage amount is not reduced, the magnetic flux is not changed, and the power density of the motor is not influenced; the rotor structure provided by the utility model can reduce the magnetic leakage amount while reducing the assembly cost, thereby improving the power density.

The invention discloses an indirect magnetic energy consistency evaluation method applied to a relay permanent magnet screening process. The method comprises the following steps: step 1, measuring residual magnetism Br and coercive force Hc of a permanent magnet; 2, sufficiently magnetizing the permanent magnet, demagnetizing the permanent magnet by using quantitative demagnetizing fields with fixed values of 1 / 3Hc, 1 / 2Hc and 2 / 3Hc according to the coercive force Hc, and recording the magnetic induction intensities B1, B2 and B3 of the permanent magnet; step 3, according to Br, B1, B2, B3 and Hc, fitting the demagnetization curve by using finite element physical constraint to obtain the demagnetization curve, and performing permanent magnet screening through the demagnetization curve; 4, calculating the product of BH point by point to obtain the maximum magnetic energy product; and step 5, evaluating the consistency of the permanent magnet through the standard deviation of the maximum magnetic energy product, the residual magnetism and the coercive force. The method can more accurately evaluate the magnetic energy consistency of the permanent magnet, and is convenient for improving the overall reliability of the relay permanent magnet.

The invention discloses a multi-cavity high-precision sub-control water-cooling demagnetization clamp and a demagnetization method, the multi-cavity high-precision sub-control water-cooling demagnetization clamp comprises a clamp body, the clamp body is internally provided with a plurality of demagnetization cavities, the demagnetization cavities generate different demagnetization intensity so as to form different demagnetization gears, the accurate adjustment of the demagnetization amount is realized, and a plurality of magnets with different magnetic grades are synchronously obtained; a plurality of demagnetization holes are formed in the magnet, a demagnetization assembly is arranged in each demagnetization hole, each demagnetization assembly comprises a lining and a winding wound on the lining, a placement cavity used for being matched with a magnet to be demagnetized is formed in the lining, magnet gathering yokes are further arranged at the two ends of the magnet respectively, and the magnet and the demagnetization field can be aligned through the magnet gathering yokes. And the consistency of the magnet in the demagnetizing process and the demagnetizing field direction is ensured, so that the waveform of the demagnetized magnet is undistorted, the demagnetizing effect of the magnet is improved, and stability and reliability are achieved.

The invention discloses an in-service equipment monitoring sensor, system and method based on high-temperature demagnetization resistance. The sensor comprises a shell, a permanent magnet, a shielding layer, a coil and a wear-resistant layer, the permanent magnet comprises a magnetic body made of a high-temperature-resistant permanent magnet material and high-permeability alloy wrapping the periphery of the magnetic body, the diameter of the magnetic body is gradually reduced from top to bottom, and a plurality of layers of high-permeability alloy wrap the upper end face and the peripheral face of the magnetic body; the magnetic body and the high-permeability alloy are combined to reconstruct the permanent magnet, the high-permeability alloy is laminated and coated on the magnetic body, and the permanent magnet and a detected object construct a low-magnetic-resistance closed magnetic circuit to inhibit the demagnetization intensity, so that the working point of the sensor is stabilized in a hysteresis loop reversible region, and the magnetic performance attenuation in a high-temperature environment is effectively inhibited.

The application discloses a kind of in-service equipment monitoring sensor based on high-temperature anti-demagnetization, monitoring system and method, sensor includes: shell, permanent magnet, shielding layer, coil, wear-resistant layer;Permanent magnet, including the magnetic body made of high-temperature-resistant permanent magnetic material, high-permeability alloy is coated on the outer periphery of the magnetic body, the diameter of the magnetic body decreases from top to bottom, and the high-permeability alloy is coated on the upper end surface and the circumferential surface of the magnetic body in several layers;The permanent magnet is reconstructed by the combination of the magnetic body and the high-permeability alloy, the high-permeability alloy is stacked and coated on the magnetic body, the permanent magnet and the detected object construct low-reluctance closed magnetic circuit to suppress the demagnetizing field strength, so that the working point of the sensor is stabilized in the reversible region of the hysteresis loop, and the magnetic property attenuation in high-temperature environment is effectively suppressed.

This invention relates to the field of novel magnetic materials, providing a high-magnetic magnetite (Fe3O4) material and its preparation method. The method includes: S1 Electrolyte immersion: cleaning the magnetite workpiece material and immersing it in an electrolyte for a set time; S2 Hydrogenation modification treatment: using the electrolyte-immersed magnetite workpiece material as a cathode, performing electrochemical atomic hydrogenation treatment. The atomic hydrogen generated by the cathode electrolysis reaction is adsorbed on the surface of the magnetite workpiece material and diffuses into the material's interior under the action of a concentration gradient, modifying the magnetite workpiece material; S3 Cleaning and drying. The magnetite material prepared by this invention has significantly improved saturation magnetization and coercivity, and enhanced remanent magnetization. The material maintains high magnetic induction intensity even under demagnetizing conditions, significantly improving the magnetic properties of magnetite. This invention's method is low-cost, simple, environmentally friendly, and conducive to industrial production.

The application discloses a sintered neodymium-iron-boron grain boundary diffusion process and system based on AI vision and multi-material gradient dispensing, and belongs to the technical field of rare earth permanent magnet material preparation. The application adopts a multi-axis motion mechanism carrying a multi-channel piezoelectric dispensing unit to real-time regulate and control the single-point glue output and slurry composition, and constructs a composition gradient diffusion source coating on the surface of the magnet which matches the demagnetizing field distribution; the application is matched with online detection closed-loop repair, segmented gradient drying, vacuum grain boundary diffusion heat treatment and post-processing procedures, and realizes self-optimization iteration of the process scheme through digital twin dynamics simulation and deep reinforcement learning algorithm. The application can realize targeted and accurate use of heavy rare earth resources, reduce the total amount of heavy rare earth while improving the coercive force and performance consistency of the magnet, adapt to flexible production of special-shaped and multi-specification magnets, and meet the green manufacturing requirements of the solvent recovery and rare earth recycling system.

The present invention provides a sintered neodymium-iron-boron magnet having high magnetic performance and high resistivity, and a preparation method therefor and a use thereof. The sintered neodymium-iron-boron magnet of the present invention comprises main phase grains and grain boundaries. Components of each main phase grain comprise R2T14B. The grain boundaries are located between the main phase grains and comprise two-grain boundaries and triple-junction boundaries. Each two-grain boundary is located between any two main phase grains, and each triple-junction boundary is located among any three or more main phase grains. The triple-junction boundaries comprise regions of a first Cu-rich phase and regions of a second Cu-rich phase. The sintered neodymium-iron-boron magnet provided by the present invention comprises two non-ferromagnetic Cu-rich phases, which can impede the propagation of a demagnetizing field among grains, thereby enhancing coercivity. In addition, the Cu-rich phases have a low Fe content, so that the propagation of electrons among the main phase grains can be impeded within the grain boundaries, and an isolation effect is achieved, thereby improving the resistivity of the magnet, and reducing the eddy current loss in motors.

A magnetic shielding device degaussing system based on an omnibearing degaussing field mainly comprises a degaussing current signal generating device and a degaussing coil, the degaussing current signal generating device is used for generating a set degaussing current signal and driving the degaussing coil to generate a degaussing field, and the degaussing field is used for generating a degaussing current signal; and the magnetic field continuously rotates, and the total magnetic field intensity is gradually attenuated along with time, so that an omnibearing oscillation attenuation demagnetization magnetic field is formed, and deep demagnetization of the magnetic shielding device is realized. According to the system, by defining the amplitude, the frequency, the duration, the envelope function, the rotating speed and the like of the demagnetization current, an all-directional demagnetization field is generated in the shielding layer, deep demagnetization of the shielding device is achieved, the residual magnetic field of the shielding device can be effectively reduced, and the stability after demagnetization is improved.

The present invention discloses a method for recycling waste NdFeB magnets, comprising the following steps: (1) demagnetizing, grinding, cleaning, and drying waste NdFeB magnets of different grades and different coercive forces; (2) subjecting the dried waste NdFeB magnets to hydrogen explosion crushing and airflow milling to obtain magnet powder particles; (3) electroplating the surfaces of the magnet powder particles with a low-melting-point metal; (4) calculating the demagnetization field distribution of a target new magnet using micromagnetic simulation software, and programming a powder filling control program in a mold based on the demagnetization field distribution; (5) filling the electroplated magnet powder particles into a mold using the filling control program, with high-coercive force magnet powder being filled into the region corresponding to the large demagnetization field, and obtaining a blank after magnet orientation and pressure treatment; (6) hot-pressing and sintering the blank to obtain a new NdFeB magnet. The present invention can achieve efficient recycling of waste NdFeB magnets of different grades and produce new high-performance NdFeB magnets.

This invention discloses a weak magnetic field measuring instrument and its measuring method, belonging to the field of weak magnetic field measurement technology. The weak magnetic field measuring instrument includes a mounting platform, on which a thin-film pressure-sensitive sensor and two soft magnets are arranged. The piezoelectric element of the thin-film pressure-sensitive sensor is disposed between the two soft magnets. The signal line of the thin-film pressure-sensitive sensor is electrically connected to an external electrical signal device. A test magnet is disposed between the two soft magnets. The two soft magnets are used to obtain an amplified magnetic field through the demagnetizing effect. Then, the amplified magnetic field is used to apply pressure to the pressure sensor through the soft magnets and the magnet between the soft magnets to output a specific signal. Finally, the magnetic field strength and direction of the external weak magnetic field are obtained using the output signal.