Nanocrystalline complex phase neodymium iron boron permanent magnet texturing enhancement preparation method

A NdFeB, permanent magnet technology, applied in magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve the problems of uneven distribution of low melting point grain boundary phase, short deformation time, flaky crystal growth, etc. , to inhibit the formation and expansion of cracks, improve densification and magnetic properties, and enhance the texture of hard magnetic phase

Active Publication Date: 2018-07-31
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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Problems solved by technology

However, the traditional heat distortion temperature is relatively high, usually above 700°C, which causes the excessive growth of flaky crystals, and the lateral size reaches several microns, far exceeding the exchange coupling size required by the soft and hard magnetic phase.
In addition, the traditional hot deformation process has short deformation time and uneven distribution of low melting point grain boundary phases, which will deteriorate the anisotropy of the composite magnet

Method used

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  • Nanocrystalline complex phase neodymium iron boron permanent magnet texturing enhancement preparation method
  • Nanocrystalline complex phase neodymium iron boron permanent magnet texturing enhancement preparation method
  • Nanocrystalline complex phase neodymium iron boron permanent magnet texturing enhancement preparation method

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Embodiment 1

[0022] In this embodiment, the raw material is commercial rare-earth-poor dual-phase magnetic powder NdFeB (15-7) purchased from Magnequench Magnetics (Tianjin) Co., Ltd., and the raw material and low melting point alloy powder Nd 70 Cu 30 mixing, the doping amount of the Nd-Cu alloy powder accounts for 8% of the mass of the raw material to obtain the doped raw material.

[0023] The preparation method of this Nd-Cu alloy powder is as follows:

[0024] (1) According to the composition of NdCu alloy, Nd is obtained by vacuum induction melting 70 Cu 30 alloy ingot;

[0025] (2) Broken the Nd under the protection of argon 70 Cu 30 Alloy ingots are ground and sieved to obtain NdCu alloy powders with a particle size below 90um;

[0026] Using this doping raw material, the anisotropic Nd 2 Fe 14 B complex phase permanent magnet block material, as follows:

[0027] (1) Hot pressing process: put the quantitative amount of the doped raw material into the cemented carbide mold,...

Embodiment 2

[0030] In this embodiment, the same doping raw materials as in Embodiment 1 are used.

[0031] Using this doping raw material, the anisotropic Nd 2 Fe 14 B complex phase permanent magnet block material, as follows:

[0032] (1) is exactly the same as the step (1) of embodiment 2;

[0033] (2) It is basically the same as step (2) of Example 2, the only difference is that the deformation rate along the pressure direction v=2um / s is controlled under the condition of 600°C to carry out hot pressing deformation to the predetermined size, and the double Composite permanent magnet block material.

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Abstract

The invention provides a nanocrystalline complex phase neodymium iron boron permanent magnet texturing enhancement preparation method. According to the method, an NdFeB complex green body obtained bythermal pressing treatment is subjected to thermal deformation treatment at a low temperature and low rate to obtain a total-compact anisotropic NdFeB complex phase permanent magnet. Compared with theconventional process, the permanent magnet is subjected to deformation and orientation at a low temperature, so that grain growth can be suppressed effectively; and meanwhile, grain boundary phase uniform distribution at a low temperature can be facilitated by thermal deformation at low rate, so that hard magnetic phase texturing can be reinforced, crack formation and expansion in the deformationprocess can be suppressed, and the compaction and magnetic performance of the block body can be improved.

Description

technical field [0001] The invention relates to the technical field of magnetic materials, in particular to a preparation method for texture enhancement of nanocrystalline composite-phase NdFeB permanent magnets. Background technique [0002] In 1993, Skomski and Coey theoretically predicted that the anisotropic nanocomposite permanent magnet has a magnetic energy product of 120MGOe, which is much higher than the theoretical value of 64MGOe of the existing powder sintered NdFeB magnet, and the rare earth content is low, which makes it expected to become the next generation magnet. A generation of high-performance, low-cost permanent magnet materials. However, experimentally fabricating such ideal nanostructures is a great challenge. [0003] Hot pressing and thermal deformation technology is an effective means to prepare fully dense anisotropic single-phase NdFeB permanent magnets. It is generally considered that the rare earth-rich phase acts as a liquid phase at the grain...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02H01F1/057H01F1/08
CPCH01F1/0576H01F41/0266H01F41/0273
Inventor 杜娟张中佳王凤青刘平郑强
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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