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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, reducing import dependence, and low prices

Inactive Publication Date: 2012-10-24
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

Method used

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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 utilizes discharge plasma technology to carry out rapid sintering to obtain fully dense isotropic nanocrystalline NdFeB bulk magnet material; then, adopts discharge plasma sintering technology to carry out thermal deformation treatment on fully dense isotropic nanocrystalline NdFeB bulk magnet material to obtain A fully dense anisotropic nanocrystalline NdFeB bulk magnet material, the preparation method of which specifically includes the following steps:

[0033] Step 1: Spark plasma sintering

[0034] After loading the HDDR magnetic powder with a particle size of 45–100 μm into the graphite mold, it is pre-pressed at 40 MPa and then sintered rapidly. The sintering process conditions are as follows:

[0035] Sintering pressure: 40MPa

[0036] Sintering temperature: 750°C

[0037] Heating rate: 100°C / min

[0038] Heat preservation time: 10min

[0039] Sintering vacuum degree: 4Pa

[0040] The fully dense isotropic nanocrystalline NdFeB bulk mag...

Embodiment 2

[0051] The present invention utilizes discharge plasma technology to carry out rapid sintering to obtain a fully dense isotropic nanocrystalline NdFeB bulk magnet material; then, adopts a discharge plasma sintering technology to thermally deform the fully dense isotropic nanocrystalline NdFeB bulk magnet material to obtain A fully dense anisotropic nanocrystalline NdFeB bulk magnet material, the preparation method of which specifically includes the following steps:

[0052] Step 1: Spark plasma sintering

[0053] After loading the HDDR magnetic powder with a particle size of 45–100 μm into the graphite mold, it is pre-pressed at 50 MPa and then sintered rapidly. The sintering process conditions are as follows:

[0054] Sintering pressure: 50MPa

[0055] Sintering temperature: 800°C

[0056] Heating rate: 120°C / min

[0057] Heat preservation time: 20min

[0058] Sintering vacuum degree: 2Pa

[0059] The fully dense isotropic nanocrystalline NdFeB bulk magnet material can b...

Embodiment 3

[0071] The present invention utilizes discharge plasma technology to carry out rapid sintering to obtain a fully dense isotropic nanocrystalline NdFeB bulk magnet material; then, adopts a discharge plasma sintering technology to thermally deform the fully dense isotropic nanocrystalline NdFeB bulk magnet material to obtain A fully dense anisotropic nanocrystalline NdFeB bulk magnet material, the preparation method of which specifically includes the following steps:

[0072] Step 1: Spark plasma sintering

[0073] After loading the HDDR magnetic powder with a particle size of 45–100 μm into the graphite mold, it is pre-pressed at 50 MPa and then sintered rapidly. The sintering process conditions are as follows:

[0074] Sintering pressure: 45MPa

[0075] Sintering temperature: 850°C

[0076] Heating rate: 150℃ / min

[0077] Holding time: 15min

[0078] Sintering vacuum degree: 4Pa

[0079] The fully dense isotropic nanocrystalline NdFeB bulk magnet material can be obtained ...

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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 in particular relates to a preparation method of a full-dense anisotropic nanocrystalline NdFeB bulk magnet material. Background technique [0002] NdFeB permanent magnet alloy, because of its high remanence, high coercive force and high magnetic energy product, has been applied in many aspects such as computer hard disk drives, motors, human magnetic resonance imagers, and audio devices. 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 binders. However, the traditional sintered NdFeB has poor temperature stability, low magnetization and low corrosion resistance due to the inhomogeneity of the structure, the existence of non-magnetic phases, and the coarse grains induced by high-temperature sintering. Compared with bonded and trad...

Claims

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Application Information

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Patent Type & Authority Applications(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