12 results about "Demagnetizing field" patented technology

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 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 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.

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.

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.

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.