A preparation method of high orientation degree sintered NdFeB permanent magnet material

A permanent magnet material, neodymium iron boron technology, applied in the direction of magnetic materials, inductors/transformers/magnet manufacturing, magnetic objects, etc., can solve the problems that affect the free orientation of crystal grains, uneven compact density, and affect density, etc., to achieve Improve the effect of uneven shrinkage, uniform density distribution and increased fluidity

Active Publication Date: 2017-11-17
UNIV OF SCI & TECH BEIJING
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Problems solved by technology

[0008] The purpose of the present invention is to solve the problems existing in the prior art that affect the sufficient free orientation of the crystal grains, and there will be overall unevenness in compact density, which will further affect the density unevenness in the sintering process, resulting in cracks, edge dropouts, etc. The problem of phenomena

Method used

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  • A preparation method of high orientation degree sintered NdFeB permanent magnet material

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Experimental program
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Embodiment 1

[0020] The particle size is 3.5μm and the component is Nd 29.5 Fe 69.1 Ga 0.2 Nb 0.2 B 1.0 The NdFeB powder particles are mixed evenly with an organic solvent (80% absolute ethanol+15% methylene chloride+3% sodium alginate+2% polyvinyl alcohol) in a hypoxic environment to obtain a slurry (NdFeB powder The volume ratio of the slurry to the organic solvent is 2:1); the slurry is poured into the mold, and oriented in a 1.8T magnetic field; the organic solvent is removed by vacuum drying to obtain the preform; the preform is vacuum-packed with a plastic film, Then put it into a hydraulic device for cold isostatic pressing, the pressing force is 200MPa; the plastic film on the green body is peeled off, and the green body is sintered at 1060°C for 3 hours in high vacuum; the sintered magnet is high vacuum at 880°C and 500°C Tempering for 2 hours; high orientation degree sintered NdFeB permanent magnet material with magnetic properties of B r =1.46T(14.6kGs),H ci =1100kA·m -1 ...

Embodiment 2

[0022] The particle size is 3.0μm and the composition is (NdPr) 30.0 Fe 68.9 Cu 0.2 Zr 0.2 B 1.0 The NdFeB powder particles are mixed evenly with an organic solvent (80% absolute ethanol+20% dichloromethane) in a hypoxic environment to obtain a slurry (the volume ratio of the NdFeB powder to the organic solvent is 3:2); The slurry is poured into the mold and oriented in a 1.8T magnetic field; then the organic solvent is removed by vacuum drying to obtain a preform; the preform is vacuum-packed with a plastic film, and then put into a hydraulic device for cold isostatic pressing, pressing The force is 200MPa; the plastic film on the green body is peeled off, and the green body is sintered in high vacuum at 1080°C for 3h; the sintered magnet is tempered in high vacuum at 900°C and 500°C for 2h respectively; high orientation degree sintered NdFeB magnets are obtained Magnetic material, magnetic property is B r =1.458T,H ci =1150kA·m -1 (14.4kOe),(BH) max =414kJ·m -3 (52....

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Abstract

Provided is a method for preparing a high-orientation-degree sintered neodymium-iron-boron permanent magnetic material. Neodymium-iron-boron powder particles and an organic solvent are mixed to prepare a slurry, and the slurry is poured into a mould; then a non-pressure orientation is performed in a magnetic field to obtain a high orientation degree; next, a blank with a certain compactness is obtained through cold isostatic pressing; and finally, a magnet is obtained by performing sintering densification and tempering thermal treatment. The slurry formed from the neodymium-iron-boron powder and the organic solvent is high in fluidity, and is not subjected to a pressing pressure in the magnetic field orientation process, such that it can be ensured that the orientation is sufficient and is not destroyed; then the blank can be rendered to reach a certain compactness and have a uniformly distributed density through cold isostatic pressing, such that not only can sintering densification be realized, but also cracks and falling off of edges and corners caused by uneven density and the like in the sintering process can be avoided, so that sintered neodymium-iron-boron permanent magnetic material having a high-orientation-degree is obtained finally.

Description

technical field [0001] The invention belongs to the field of rare earth permanent magnet materials, in particular to a preparation method of sintered NdFeB permanent magnet materials with high orientation degree. technical background [0002] The sintered NdFeB permanent magnet material known as the "Magnetic King" has become the core functional material in the fields of electric power, telecommunications, automobiles, computers, biomedicine and household appliances, and is being used to manufacture hundreds of kilowatts of electric (or hybrid electric) Automobile generators, motors, and permanent magnet motors for wind power generation on the order of megawatts. [0003] According to the theory of ferromagnetism, the remanence of polycrystalline orientation composite phase permanent magnet materials is determined by the following formula: [0004] [0005] where A is the volume fraction of the positive phase domain; β is the volume fraction of the nonmagnetic phase; (1–...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F41/02H01F1/057
CPCH01F1/057H01F41/02
Inventor 高学绪曹帅包小倩汤明辉卢克超
Owner UNIV OF SCI & TECH BEIJING
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