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Method for preparing fully dense anisotropic nanocrystalline neodymium-iron-boron (NdFeB) bulk magnet material

An anisotropic and nanocrystalline technology, applied in the direction of magnetic materials, magnetic objects, electrical components, etc., can solve the problem of easy damage of WC molds, achieve the effects of improving magnetic properties, saving production costs, and reducing import dependence

Inactive Publication Date: 2014-02-26
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to overcome the technical problems of using HDDR magnetic powder as the initial material in the prior art, and the WC mold is easily damaged when the spark plasma sintering equipment is subjected to thermal deformation treatment, and to provide a fully dense anisotropic nanocrystalline NdFeB block magnet material preparation method

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  • Method for preparing fully dense anisotropic nanocrystalline neodymium-iron-boron (NdFeB) bulk magnet material
  • Method for preparing fully dense anisotropic nanocrystalline neodymium-iron-boron (NdFeB) bulk magnet material
  • Method for preparing fully dense anisotropic nanocrystalline neodymium-iron-boron (NdFeB) bulk magnet material

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Embodiment 1

[0032] The present invention uses spark plasma technology to rapidly sinter to obtain fully dense isotropic nanocrystalline NdFeB bulk magnet material; then, using spark plasma sintering technology to perform thermal deformation treatment on the fully dense isotropic nanocrystalline NdFeB bulk magnet material to obtain The preparation method of the fully dense anisotropic nanocrystalline NdFeB bulk magnet material specifically includes the following steps:

[0033] Step 1: Spark plasma sintering

[0034] After the HDDR magnetic powder with a particle size of 45-100μm is put into a graphite mold, after 40MPa preloading, rapid sintering is carried out. The sintering process conditions are as follows:

[0035] Sintering pressure: 40MPa

[0036] Sintering temperature: 750℃

[0037] Heating rate: 100℃ / min

[0038] Holding time: 10min

[0039] Sintering vacuum degree: 4Pa

[0040] After rapid sintering, a fully dense isotropic nanocrystalline NdFeB bulk magnet material can be obtained.

[0041] ...

Embodiment 2

[0051] The present invention uses spark plasma technology to rapidly sinter to obtain fully dense isotropic nanocrystalline NdFeB bulk magnet material; then, using spark plasma sintering technology to perform thermal deformation treatment on the fully dense isotropic nanocrystalline NdFeB bulk magnet material to obtain The preparation method of the fully dense anisotropic nanocrystalline NdFeB bulk magnet material specifically includes the following steps:

[0052] Step 1: Spark plasma sintering

[0053] The HDDR magnetic powder with a particle size of 45-100μm is put into a graphite mold, and after 50MPa pre-compression, fast sintering is carried out. The sintering process conditions are as follows:

[0054] Sintering pressure: 50MPa

[0055] Sintering temperature: 800℃

[0056] Heating rate: 120℃ / min

[0057] Holding time: 20min

[0058] Sintering vacuum degree: 2Pa

[0059] After rapid sintering, a fully dense isotropic nanocrystalline NdFeB bulk magnet material can be obtained, and it...

Embodiment 3

[0071] The present invention uses spark plasma technology to rapidly sinter to obtain fully dense isotropic nanocrystalline NdFeB bulk magnet material; then, using spark plasma sintering technology to perform thermal deformation treatment on the fully dense isotropic nanocrystalline NdFeB bulk magnet material to obtain The preparation method of the fully dense anisotropic nanocrystalline NdFeB bulk magnet material specifically includes the following steps:

[0072] Step 1: Spark plasma sintering

[0073] The HDDR magnetic powder with a particle size of 45-100μm is put into a graphite mold, and after 50MPa pre-compression, fast sintering is carried out. The sintering process conditions are as follows:

[0074] Sintering pressure: 45MPa

[0075] Sintering temperature: 850℃

[0076] Heating rate: 150℃ / min

[0077] Holding time: 15min

[0078] Sintering vacuum degree: 4Pa

[0079] After rapid sintering, a fully dense isotropic nanocrystalline NdFeB bulk magnet material can be obtained.

[0080...

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Abstract

The invention discloses a method for preparing a fully dense anisotropic nanocrystalline neodymium-iron-boron (NdFeB) bulk magnet material. The method includes using a discharge plasma technology to perform a rapid sintering to obtain a fully dense isotropic nanocrystalline NdFeB bulk magnet material, and then using a spark plasma sintering technology to subject the fully dense isotropic nanocrystalline NdFeB bulk magnet material to a thermal deformation processing to obtain the fully dense anisotropic nanocrystalline NdFeB bulk magnet material. According to the method, hydrogenation-disproportionation-desorption-recombination (HDDR) is used as an initial raw material, the source is rich, the cost is low, the magnetic performance of the prepared magnet material can be remarkably improved, and the magnet material can be widely applied to mobile phone speakers, computer hard disk drives and the like. By means of the method, during the thermal deformation processing, a tantalum sheet is used for separating the bulk magnet material from a wolfram carbide (WC) mould, the problem that the WC mould is prone to be damaged is effectively solved, the process is simple, further the production cost is saved, and the production efficiency is increased.

Description

Technical field [0001] The invention belongs to the field of magnetic material preparation, and particularly relates to a method for preparing a fully dense anisotropic nanocrystalline NdFeB bulk magnet material. Background technique [0002] NdFeB permanent magnet alloy, because of its high remanence, high coercivity and high magnetic energy product, has been applied in many aspects such as computer hard disk drives, motors, human MRI machines, audio devices and so on. The preparation methods of NdFeB permanent magnet materials mainly include sintering, thermal deformation and bonding. The magnetic properties of bonded NdFeB are generally low due to the addition of the binder. However, traditional sintered NdFeB has poor temperature stability, low magnetization and low corrosion resistance due to the uneven structure, the existence of non-magnetic phases, and the coarse grains induced by high temperature sintering. Compared with bonded and traditional sintered NdFeB, hot-defor...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F3/105B22F3/24H01F1/057
CPCH01F1/0576H01F1/0577
Inventor 李小强陈志成敖敬培屈盛官杨超
Owner SOUTH CHINA UNIV OF TECH