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A kind of method for preparing rare earth permanent magnet material

A rare-earth permanent magnet and rare-earth-rich alloy technology, which is applied in the direction of magnetic materials, inorganic materials, magnetic objects, etc., can solve the problems of small magnet grains, low material utilization rate, and high material utilization rate, and achieve small product deformation and high material utilization. High utilization rate and good fluidity of magnetic powder

Active Publication Date: 2019-03-29
ZHEJIANG DONGYANG DMEGC RARE EARTH MAGNET CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The biggest disadvantage of bonded NdFeB magnets is low magnetic performance, and the magnetic energy product of bonded NdFeB magnets is mostly 60-90kJm -3
[0006] In summary, the advantages of sintered NdFeB magnets are that the magnetic powder is cheap, the production process is simple, the efficiency is high, and the cost is low; the disadvantage is that the material utilization rate is low, and it is easy to deform and crack
The advantages of hot-pressed / heat-deformed magnets are that the magnet grains are small and the material utilization rate is high; the disadvantages are that the price of magnetic powder (special quick-quenching powder for hot-pressed / heat-deformed) is high, the heat-deformation efficiency is low, and the cost is high
The advantage of bonded NdFeB magnets is that the material utilization rate is high, and the production of special-shaped magnets can be realized; the main disadvantage is that the magnetic performance is low, and the magnetic energy product of bonded NdFeB magnets is mostly 60-90kJm -3

Method used

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  • A kind of method for preparing rare earth permanent magnet material

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] 1. Change the composition to Nd 26.25 PR 8.75 Fe 64 B 1 (mass percentage content) of sintered NdFeB blank mechanically crushed into particles with an average particle diameter of 200 μm;

[0027] 2. Apply a magnetic field of 1T, the size of the green body is R8.1×R3.6×10, and the weight of the green body is 29.97g;

[0028] 3. Put the green body in the cavity of the pressure sintering mold, the pressure sintering mold is in a closed space, first evacuate to 8×10 -3 Pa, then filled with argon to 8×10 4 Pa, then raise the temperature to 850°C, pressurize 200MPa along the thickness direction of the sintered NdFeB green body, hold the pressure for 6 minutes, and then cool it out;

[0029] 4. Put the pressure-sintered magnet into a vacuum furnace for heat treatment, and heat-treat the hot-pressed blank by using 900°C for 4 hours and 500°C for 4 hours to obtain a specification of R8.1×R3.6×5.3 High-quality magnets have a material utilization rate of 100%, no corner crac...

Embodiment 2

[0031] will be composed as Nd 26.25 PR 8.75 Fe 64 B 1 (mass percent content) sintered NdFeB blanks are mechanically broken into particles with an average particle size of 50 μm. Add 5% Nd to polycrystalline NdFeB particles 70 Cu 30 (mass percent content) rare earth-rich alloy powder, wherein the average particle diameter of the neodymium-copper alloy powder is 3 μm. The temperature during pressure sintering was 700° C., and other processes were the same as in Example 1.

Embodiment 3

[0033] Wash and dry the leftovers of sintered NdFeB and break them into 300μm polycrystalline particles, then add 5% Nd 70 Cu 30 (mass percentage content) the rare earth-rich alloy powder, the average particle diameter of the neodymium-copper alloy powder is 3 μm. A circular green body of φ30×φ24×20 was prepared by orientation with a 0.5T radiation magnetic field. The temperature during pressure sintering is 650 degrees centigrade, and other processes are the same as in embodiment 1.

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Abstract

A method for preparing rare-earth permanent magnetic materials, comprising the following steps: selecting a sintered neodymium iron boron (NdFeB) blank, a waste NdFeB magnet or NdFeB scrap after washing and stoving, breaking same down into NdFeB powder; applying an oriented magnetic field to the NdFeB powder to turn the latter into a NdFeB green part; placing the NdFeB green part within the cavity of a pressure sintering mold, the pressure sintering mold being in a hermetically sealed space, under a vacuum or the protection of insert gas, heating and pressurizing to perform the pressure sintering, and then cooling and taking out; placing the pressure-sintered magnet within a vacuum furnace to perform heat treatment for secondary tempering, and obtaining a NdFeB magnet. The method has advantages of good magnetic powder flowability, high production efficiency, small product deformation and less crack; the oriented magnetic field is low, and a stable mass production of special oriented magnet such as a radiation ring can be realized; pressure sintering is performed by using the pressure sintering mold, the dimensions of the magnet are approximate to the dimensions of a final finished product, the material utilization and the magnetic property are high, and cost is low.

Description

technical field [0001] The invention relates to the technical field related to magnetic materials, in particular to a method for preparing rare earth permanent magnet materials. Background technique [0002] Since the advent of NdFeB magnets in the 1980s, they have been widely used in electronics, communications, transportation, automation, medical and new energy fields due to their excellent magnetic properties. So far, NdFeB permanent magnet material is the permanent magnet material with the best comprehensive magnetic properties. It is known as the "magnet king" and is of great significance to the miniaturization, integration and high efficiency of devices. [0003] According to the preparation method, NdFeB magnets are mainly divided into sintered, bonded, hot-pressed / thermally deformed magnets, among which sintered NdFeB magnets are used in the largest amount. The preparation process of sintered NdFeB magnets is mainly to obtain NdFeB alloy by quick-setting process, an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/057H01F1/08B22F3/14B22F3/10B22F3/24
CPCH01F1/057
Inventor 郝忠彬韩相华洪群峰章晓峰
Owner ZHEJIANG DONGYANG DMEGC RARE EARTH MAGNET CO LTD
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