A kind of preparation method of rare earth permanent magnet material

A rare earth permanent magnet and rare earth rich alloy technology, applied in the direction of magnetic materials, inorganic material magnetism, magnetic objects, etc., can solve the problems of high material utilization, small magnet grains, high cost, low densification temperature, inhibit crystallinity, etc. The effect of grain growth and high production efficiency

Active Publication Date: 2017-12-22
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 sintering temperature is high (above 1040 ° C), the magnet grains are easy to grow, the material utilization rate is low, and it is easy to deformation cracking
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 preparation method of rare earth permanent magnet material

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Effect test

Embodiment 1

[0029] 1. The NdFeB alloy is prepared in a vacuum melting furnace, and the alloy whose main alloy composition is Nd26.25Pr8.75Fe64B1 (mass percentage content) is made into thin slices by using the quick-setting thin slice technology; The flakes are made into a powder with an average particle size of 3.5 μm;

[0030] 2. Apply a magnetic field of 1.5T, and obtain a blank with a size of R8.1×R3.6×10 and a blank weight of 29.97g;

[0031] 3. Put the blank obtained by the primary molding into the mold of the secondary molding. The mold of the secondary molding 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 780°C, pressurize 200MPa along the direction of thickness 10, hold the pressure for 6 minutes, cool and take it out;

[0032] 4. Put the secondary molded magnet into a vacuum furnace for secondary heat treatment, and heat-treat the hot-pressed blank by adopting the process of holding at 900°C for 8 hours an...

Embodiment 2

[0034] 1, adopt the magnet among the embodiment 1, add 5%Nd70Cu30 (mass percentage composition) rich rare earth alloy powder in the neodymium-iron-boron alloy powder that makes after step 1, wherein the average particle diameter of neodymium-copper alloy powder is 3 μ m;

[0035] 2. In step 3, the hot pressing temperature is 680° C., and other processes are the same as in embodiment 1.

Embodiment 3

[0037] After the heat treatment in Step 4, the magnet in Example 2 was subjected to a stress relief tempering treatment at 340° C. for 2.5 hours.

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Abstract

A method for manufacturing a rare-earth permanent magnetic material comprises manufacturing a NdFeB magnetic from NdFeB alloy powder by two consecutive compression molding processes. An oriented magnetic field is applied in the first molding process to obtain an anisotropic NdFeB green body, and heating and pressing are applied in the second molding process to obtain a dense NdFeB magnetic having a size close to that of a final product. The performance of the magnetic is enhanced through a special thermal treatment process, which involves a low densification temperature that suppresses the enlargement of crystals, and thus provides crystals that are smaller compared to those of a sintered magnet and that have high magnetic performance. By adopting the molding processes, the size of a magnet is close to that of a final product, and the material utilization rate is much greater than that of a conventional sintered NdFeB magnet. Further, the method does not require a dedicated fast-quench magnetic powder or thermal deformation, providing a simple process, high production efficiency, production costs far lower than those of a thermal pressed / thermal deformed magnetic, and high magnetic performance achieving a maximum magnetic energy product above 200 kJm-3, much higher than that of a bonded NdFeB magnet.

Description

technical field [0001] The invention relates to the technical field related to magnetic materials, in particular to a preparation method of a rare earth permanent magnet material. 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, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/057H01F1/08B22F3/14B22F3/24
CPCB22F3/14B22F3/24H01F1/057H01F1/08
Inventor 郝忠彬韩相华章晓峰洪群峰
Owner ZHEJIANG DONGYANG DMEGC RARE EARTH MAGNET CO LTD
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