Abstract: A method for preparing a high coercivity grain boundary diffusion neodymium iron boron (NdFeB) magnet by high-pressure torsion, including: Step 1: mixing a NdFeB powder and a heavy rare earth powder, and grinding to achieve uniform mixing to obtain a composite powder; Step 2: pre-pressing the composite powder into a block magnet; Step 3: placing the block magnet in a high-pressure torsion device to cause nucleation, elongation, and refinement to obtain a sheet magnet; and Step 4: performing a diffusion heat treatment on the sheet magnet under a vacuum condition to produce in-situ grain boundary diffusion, and obtaining a high coercivity NdFEB magnet.

Abstract: A device and method for detecting Curie temperature of a permanent magnet material is provided, and relates to the technical field of magnetic material detection. The device includes a detection coil, two ends of the detection coil are respectively fixed by a sample fixing tube; a temperature test box arranged inside the detection coil, the temperature test box is provided with a piercing hole for a permanent magnet material sample to be tested to pass in and out, the temperature test box is communicated with a temperature control device; a temperature sensor arranged in the temperature test box; and a magnetic flux integrator connected with the detection coil.

Abstract: A magnetic material and method prepares high-performance composite ferrite for a self-biased circulator. The preparation method includes: (1) preparing BaM ferrite initial powder and NiCuZnSn ferrite initial powder, respectively; (2) mixing the BaM ferrite initial powder, the NiCuZnSn ferrite initial powder and deionized water uniformly in proportion, performing ball milling in a high-energy ball mill, and then obtaining mixed powder after primary pre-sintering, secondary pre-sintering and secondary ball milling; and (3) obtaining the high-performance composite ferrite for the self-biased circulator by a low-temperature magnetic field orientation forming technology and magnetic field heat treatment.

Abstract: The present disclosure discloses a rapid measuring device and a measuring method for permanent magnet failure temperature. The device includes a measurement system (1), an infrared thermal imager (2), a vacuum Hall probe (3) and a laser heating device (4). A permanent magnet (5) is used as a sample. These components work together to achieve rapid and accurate measurement of the failure temperature of the permanent magnet sample (5). The present disclosure uses light heating, infrared thermal imaging and surface magnetic field measurement. The heating speed is fast, the temperature measurement is accurate, and the failure temperature measurement of large permanent magnet materials can be achieved.

Abstract: A device for measuring magnetism of a permanent magnet material at a high temperature includes a laser device, a power controller, a light beam controller, a temperature controller, a magnetism measurement unit, temperature sensors, and electromagnet pole heads. The electromagnet pole heads are divided into an upper piece and a lower piece for clamping upper and lower surfaces of a sample. Heat absorbing sheets are respectively fixed on front and rear surfaces of the sample. Temperatures of the heat absorbing sheets are measured by the temperature sensors. The sample is heated by laser, and the temperature controller is used to adjust a ratio of light beams of the power controller and the light beam controller irradiating the heat absorbing sheets on the front and rear surfaces of the sample, thus adjusting the temperatures of the heat absorbing sheets. The magnetism of the sample is measured using the magnetism measurement unit.

Abstract: The present invention discloses a high-resistivity sintered samarium-cobalt magnet and a preparation method thereof. According to the present invention, considering the specialty of sintered samarium-cobalt magnetic powder, fluoride or oxide is firstly prepared into nano-powder using high-energy ball milling, and the samarium-cobalt magnetic powder is prepared separately by rolling ball milling or high-speed jet milling, and then a certain electric field is applied in a fluoride suspension to drive the fluoride nano-powder to evenly cover a surface of the samarium-cobalt magnetic powder. The present invention breaks through the technical bottleneck that fluoride/oxide can improve the resistivity of a samarium-cobalt magnet but result in deterioration of the magnetic properties.

Abstract: A device for measuring magnetism of a permanent magnet material at a high temperature includes a laser device, a power controller, a light beam controller, a temperature controller, a magnetism measurement unit, temperature sensors, and electromagnet pole heads. The electromagnet pole heads are divided into an upper piece and a lower piece for clamping upper and lower surfaces of a sample. Heat absorbing sheets are respectively fixed on front and rear surfaces of the sample. Temperatures of the heat absorbing sheets are measured by the temperature sensors. The sample is heated by laser, and the temperature controller is used to adjust a ratio of light beams of the power controller and the light beam controller irradiating the heat absorbing sheets on the front and rear surfaces of the sample, thus adjusting the temperatures of the heat absorbing sheets. The magnetism of the sample is measured using the magnetism measurement unit.

Abstract: The present invention discloses a high-resistivity sintered samarium-cobalt magnet and a preparation method thereof. According to the present invention, considering the specialty of sintered samarium-cobalt magnetic powder, fluoride or oxide is firstly prepared into nano-powder using high-energy ball milling, and the samarium-cobalt magnetic powder is prepared separately by rolling ball milling or high-speed jet milling, and then a certain electric field is applied in a fluoride suspension to drive the fluoride nano-powder to evenly cover a surface of the samarium-cobalt magnetic powder. The present invention breaks through the technical bottleneck that fluoride/oxide can improve the resistivity of a samarium-cobalt magnet but result in deterioration of the magnetic properties.

Abstract: The present invention discloses a method for preparing high-performance anisotropic rare-earth-free permanent magnets, comprising the steps of: forming alloy ingots by melting according to a nominal composition of MnxBi100-x, (45?×?55); then coarsely crushing the alloy ingots and passing the crushed material through a 100-mesh sieve to obtain coarse powder; putting an appropriate amount of MnxBi100-x alloy coarse powder obtained into a ball-milling tank together with non-magnetic steel balls, with a ratio of ball to powder of 10:1; adding an appropriate amount of ethanol as solvent, and then adding a non-ionic surfactant polyvinylpyrrolidone (PVP) accounting for 5-15% of the power mass to assist in low-energy ball milling; washing the slurry obtained in anhydrous ethyl alcohol, and orientating and curing the washed magnetic powder in a magnetic field after adding binder to obtain high-performance anisotropic Mn—Bi alloy magnets finally.

Abstract: Disclosed are methods for preparing a high-performance soft magnetic composites and magnetic toroidal cores thereof. A spherical soft magnetic alloy particle is coated with an insulating layer to form a mixed powder, and the mixed powder is loaded into a mold and subjected to a compression molding. An external magnetic field is applied during the compression molding of the mixed powder, and the external magnetic field is parallel to a working magnetic circuit plane and perpendicular to a normal direction of the working magnetic circuit plane. Then a stress-relief annealing is performed to obtain the high-performance soft magnetic composite.