Preparation method of sintered neodymium-iron-boron magnet with high corrosion resistance and high coercivity

A high coercive force, neodymium iron boron technology, applied in the direction of magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc.

Inactive Publication Date: 2021-04-30
EARTH PANDA ADVANCE MAGNETIC MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The present invention aims at the deficiencies existing in the prior art, and provides a preparation method of high corrosion resistance and high coercive force s...

Method used

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  • Preparation method of sintered neodymium-iron-boron magnet with high corrosion resistance and high coercivity
  • Preparation method of sintered neodymium-iron-boron magnet with high corrosion resistance and high coercivity

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Experimental program
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Embodiment 1

[0027] (1) The average particle size is 2.0μm (La 0.1 Nd 0.9 ) 31 Fe 67.6 B(CoZr) 0.2 The alloy powder and the Al powder with an average particle size of 10 nm were fully mixed according to the ratio of 99.9:0.1, and the mixing time was 2 hours to obtain a mixture.

[0028] (2) Place the mixture in a 1.8T magnetic field to make a green compact through a vibration orientation pressing;

[0029] (3) Carry out high-temperature sintering treatment on the compact, the sintering temperature is 1100°C, and the sintering time is 3h to obtain a sintered NdFeB magnet;

[0030] (4) A layer of Tb is deposited on the surface of the sintered NdFeB magnet by magnetron sputtering, and the grain boundary diffusion treatment is carried out at 700 ° C for 20 hours; followed by two-stage tempering heat treatment, wherein the first-stage tempering process includes: the temperature is 900°C, the time is 6h; the secondary tempering process includes: the temperature is 480°C, and the time is 6h....

Embodiment 2

[0032] (1) The (Ce 0.2 Nd 0.8 ) 33 Fe 61.1 B 0.9 (Co 0.9 Nb 0.1 ) 5 The alloy powder and the Cu powder with an average particle size of 500nm were fully mixed according to 99:1, and the mixing time was 6h to prepare the mixture.

[0033] (2) Place the mixture in a 2.0T magnetic field to form a green compact through two times of vibration orientation pressing;

[0034] (3) Carry out high-temperature sintering treatment to the compact, the sintering temperature is 1000°C, and the sintering time is 10h to obtain a sintered NdFeB magnet;

[0035] (4) A layer of terbium hydride is deposited on the surface of the sintered NdFeB magnet by spraying method, and the grain boundary diffusion treatment is carried out at 750 ° C for 10 h; followed by tempering heat treatment, the first-level tempering process includes: the temperature is 910 ° C, the time is 5h; The secondary tempering process includes: the temperature is 520°C, and the time is 4h. Finally, a sintered NdFeB magnet...

Embodiment 3

[0037] (1) The average particle size is 3.0μm (Pr 0.25 Nd 0.75 ) 30 Fe 66.9 B 1.1 co 2 The alloy powder and the Ga powder with an average particle size of 300nm were thoroughly mixed at a ratio of 98:2, and the mixing time was 10 hours to obtain a mixture.

[0038] (2) The mixture is placed in a 2.2T magnetic field to form a green compact through three times of vibration orientation pressing;

[0039] (3) Carry out high-temperature sintering treatment to the compact, the sintering temperature is 1050 ° C, and the sintering time is 6 hours to obtain a sintered NdFeB magnet;

[0040] (4) A layer of terbium fluoride is deposited on the surface of the sintered NdFeB magnet by electrophoretic deposition method, and the grain boundary diffusion treatment is carried out at 850 ° C for 1 h; followed by tempering heat treatment, the primary tempering process includes: the temperature is 920 ° C, The time is 3h; the secondary tempering process includes: the temperature is 600°C, a...

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Abstract

The invention discloses a preparation method of a sintered neodymium-iron-boron magnet with high corrosion resistance and high coercive force, which comprises the following steps: fully mixing neodymium-iron-boron alloy powder with nanoscale low-melting-point metal according to a certain mass ratio, putting the mixture into a magnetic field of 1.8 T or above, and carrying out oriented compression to obtain a pressed blank; and then carrying out high-temperature sintering on the pressed blank, carrying out grain boundary diffusion heavy rare earth treatment on the prepared sintered neodymium-iron-boron magnet, and finally carrying out tempering heat treatment. According to the preparation method, the grain boundary is doped with the nanoscale low-melting-point metal, so that the chemical activity of a grain boundary rare earth-rich phase can be reduced; in addition, a smoother diffusion channel is provided for grain boundary diffusion, so that the problem of grain boundary diffusion depth is solved, and controllable preparation of the sintered neodymium-iron-boron magnet with high corrosion resistance and high coercivity is realized.

Description

technical field [0001] The invention belongs to the field of magnetic materials, and in particular relates to a preparation method of a sintered NdFeB magnet with high corrosion resistance and high coercive force. Background technique [0002] As the sintered NdFeB magnet with the highest comprehensive magnetic performance at present, it is known as the contemporary "magnet king" and is widely used in wind power generation, new energy vehicles, household appliances, medical equipment, and national defense and military industries. The biggest disadvantage of sintered NdFeB magnets is the extremely poor corrosion resistance. This is because sintered NdFeB magnets belong to a multi-phase structure, and the potential difference between each phase is large, especially the rare earth-rich rare earth between the main phase grains. The phase has the highest chemical activity and is extremely prone to corrosion in a corrosive environment, eventually causing the magnet to fail due to ...

Claims

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Application Information

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IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/0577H01F41/0253H01F41/0266H01F41/0293
Inventor 曹玉杰刘友好吴玉程查善顺莫军黄秀莲刘家琴陈静武衣晓飞
Owner EARTH PANDA ADVANCE MAGNETIC MATERIAL
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