Abstract: The present invention discloses a method for preparing Nd—Fe—B-diffused permanent magnets based on pressure gradients, involving the steps preparing a Nd—Fe—B permanent magnet precursor through a mechanical grinding process, a press molding process, and a sintering process; cutting the Nd—Fe—B permanent magnet precursor into a Nd—Fe—B permanent magnet sample with a lateral size of 80-150 ?m and a thickness of 5-20 ?m; and forming a film of rare earth elements or other metal elements on one side of the Nd—Fe—B permanent magnet sample by magnetron sputtering as a diffusion source, so as to obtain a lateral heterojunction structure. For this method, it is possible to enable the rare earth elements to efficiently and uniformly penetrate the Nd2Fe14B grains and the grain boundaries, so as to noticeably enhance coercivity and thermal stability of materials without damaging crystalline orientation, reducing magnetic energy product loss and improving overall performance of permanent magnets.

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: The present invention discloses a reference sample suitable to calibrate a magnetic microscope's probe tip and a calibration method. The reference sample is a magnetic micro-nanostructure made of a magnetic material and formed on the surface of a substrate material, has at least one group of magnetic micro-nano structures composed of a plurality of substructures, and can generate a magnetic field with a specific spatial distribution on the surface of the sample. The reference sample is used to calibrate a magnetic microscope's probe tip. The magnetic material is configured to provide magnetic micro-nano structures that contain a variety of spatial feature size patterns, which can generate a stable magnetic field with specific spatial distribution on the sample surface. The present invention can broaden the spatial frequency range for calibrating the magnetic probe and realize the quantitative measurement to magnetic fields on the surface of different magnetic micro-nano structures.

Abstract: 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.

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.