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Method for improving performance of rare-earth permanent magnetic material by high temperature compressive stress

A rare earth permanent magnet and material performance technology, applied in the manufacture of magnetic materials, magnetic objects, inductors/transformers/magnets, etc., can solve the problem of affecting the dispersion uniformity of rare earth elements, the overall coercivity of the magnet is not obvious, and the coercivity improvement effect limited problems, to achieve good control accuracy, solve the problem of diffusion consistency, and improve flexibility

Active Publication Date: 2017-07-14
宁波金鸡强磁股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] We know that in the grain boundary diffusion of the magnet, the heavy rare earth enters the magnet from the surface, so the use of grain boundary diffusion to increase the coercive force of the magnet is limited by the thickness of the magnet, that is, when the magnet is thinner, the effect of increasing the coercive force of the magnet is more obvious, while For thicker magnets, the concentration of heavy rare earth atoms is distributed in a gradient from the surface to the center, and the effect of increasing the coercive force at the most central position is very limited, resulting in the overall coercive force of the magnet is not obvious, and the squareness is poor
In addition, the existing process has low dysprosium / terbium penetration efficiency, uneven magnet surface, and low degree of automation, which is not conducive to mass production
In the prior art, the addition and diffusion of heavy rare earth elements in magnets is achieved by mixing heavy rare earth powders (such as nano-scale or micron-scale powders with smaller particle sizes) with magnet alloy powders. This solution is limited by the specific gravity Factors such as different particle sizes make it difficult to achieve complete mixing uniformity during the mixing process, and in the sintering process, the particles in the form of powder are prone to flow and agglomerate due to the difference in melting point, which will greatly affect the magnet. Uniformity of Rare Earth Element Dispersion

Method used

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  • Method for improving performance of rare-earth permanent magnetic material by high temperature compressive stress
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  • Method for improving performance of rare-earth permanent magnetic material by high temperature compressive stress

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Embodiment 1

[0029] In this embodiment, the method for improving the properties of rare earth permanent magnet materials by high temperature compressive stress includes at least the following steps: attaching heavy rare earth compounds to the surface of the sintered magnet, heating and applying compressive stress at high temperature to obtain the magnet.

[0030] Different from the above-mentioned embodiments, in the method for improving the performance of rare earth permanent magnet materials under high temperature compressive stress: when the heavy rare earth compound is attached to the surface of the magnet, the protective gas atmosphere (the protective gas atmosphere is a nitrogen atmosphere or a helium atmosphere or an argon atmosphere or a nitrogen atmosphere) Argon mixed gas atmosphere or nitrogen-helium mixed gas atmosphere or helium-argon mixed gas atmosphere or nitrogen, helium, argon mixed gas atmosphere, the atmosphere pressure is preferably 1 atm, the same below).

[0031] Diff...

specific Embodiment 1

[0051] In the manufacturing method of the rare earth permanent magnet in this embodiment, the prepared NdFeB magnet is cut into thin slices, degreased, pickled, and dried, and the heavy rare earth compound is evenly adhered to the magnet by a cemented carbide roller. The surface was dried at high temperature and then passed through the internal heating high-temperature roller to apply a certain compressive stress. After cooling, the magnet was taken out and subjected to aging treatment to obtain test sample 1 and test sample 2.

[0052] The preparation of the above-mentioned NdFeB magnets includes smelting, hydrogen breaking, jet milling, molding, sintering and other treatments. The magnet is not subjected to high-temperature aging treatment, and is cut into a large square magnet of 50mm*60mm*10mm (this magnet is used as the original sample for comparison).

[0053] The thickness of the sheet magnet is controlled to be 10mm, and after degreasing, pickling, and drying, the surf...

specific Embodiment 2

[0061] In the manufacturing method of the rare earth permanent magnet in this embodiment, the prepared NdFeB magnet is cut into thin slices, degreased, pickled, and dried, and the heavy rare earth compound is evenly adhered to the surface of the magnet through a stainless steel roller. After high-temperature drying, the stainless steel high-temperature rollers are used to apply a certain compressive stress. After cooling, the magnets are taken out and subjected to aging treatment to obtain test samples 1 and 2.

[0062] The preparation of the above-mentioned NdFeB magnets includes smelting, hydrogen breaking, jet milling, molding, sintering and other treatments. The magnet is not subjected to high-temperature aging treatment, and is cut into a large square magnet of 50mm*60mm*10mm (this magnet is used as the original sample for comparison).

[0063] The thickness of the sheet magnet is controlled to be 10mm, and after degreasing, pickling, and drying, the surface is kept free ...

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Abstract

The invention discloses a method for improving the performance of a rare-earth permanent magnetic material by high temperature compressive stress. The method for improving the performance of the rare-earth permanent magnetic material by high temperature compressive stress at least comprises the following steps: attaching heavy rare-earth compounds to the surface of the sintered magnet; and obtaining the magnet through heating and applying compressive stress at high temperature. According to the invention, the problems of the limitation of the magnet specification and dimension and the inconsistency of the heavy rare-earth diffusion in the traditional process can be overcome by improving the diffusion depth of magnet, therefore, the diffusion effect is enhanced, the magnet can obtain better magnetic performance, the equipment investment is simple, the cost is lower, and the invention is suitable for large-scale promotion.

Description

technical field [0001] The invention relates to a method for improving the performance of rare earth NdFeB magnetic materials, especially a method for improving the coercive force of magnets, especially a method for improving the performance of rare earth permanent magnet materials under high-temperature compressive stress. Background technique [0002] Since the invention of NdFeB magnets in the 1980s, due to their ultra-high performance characteristics, they have been widely used in electronics, new energy, aerospace, medical, and information fields. With the development of technology, the market demand for high-grade magnets is becoming more and more extensive. New technologies represented by pressureless sintering, grain refinement, and heavy rare earth diffusion are becoming the research and development focus of various research institutes and NdFeB enterprises. Due to the unstable price of rare earths in recent years, it is a consensus to develop low-heavy rare earths ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02H01F1/057
CPCH01F1/0576H01F1/0577H01F41/0266H01F41/0293
Inventor 蔡岭文王会杰赵家成张勇
Owner 宁波金鸡强磁股份有限公司
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