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Preparation method of NdFeB magnet powder

A technology of NdFeB and magnets, applied in the direction of magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve the problems of reduced magnetic properties of magnets, easy oxidation, etc., to improve remanence, increase orientation, strong The effect of antioxidant

Active Publication Date: 2018-11-20
京磁材料科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The invention solves the problem that the sintered NdFeB permanent magnet material is prone to oxidation during the production process, which leads to the reduction of the magnetic properties of the magnet. It will change the traditional hydrogen explosion powder production process, and strengthen the powder resistance during the powder preparation process. Oxidation, improve the magnetic properties of sintered NdFeB magnets

Method used

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  • Preparation method of NdFeB magnet powder
  • Preparation method of NdFeB magnet powder
  • Preparation method of NdFeB magnet powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Validated with 50H sintered NdFeB material, the raw material composition is shown in Table 1 below:

[0033] element

[0034] First, according to the above formula, prepare 600Kg of raw materials, in which iron rods are derusted, rare earth materials are treated with oil-free, moisture-free and rust-free treatment, and the prepared raw materials are melted under the condition of medium frequency induction heating by vacuum melting (SC) , And finally obtain a sheet-like fast-quenched NdFeB alloy with columnar crystal structure.

[0035] Then, hydrogen is absorbed in a hydrogen crusher and crushed into millimeter-sized coarse particles. The medium crusher further crushes the particles, and then uses high-pressure nitrogen gas to grind uniform micron-sized powder with an average particle size of 4.0-4.5μm.

[0036] Then the jet mill powder is dehydrogenated and mechanically mixed through a dehydrogenation vessel, and the vacuum is evacuated to below 0.1Pa. The dehydrogenation ...

Embodiment 2

[0057] Validated with 42UH sintered NdFeB material, the raw material composition is shown in Table 6 below:

[0058] element

[0059] First, according to the above formula, prepare 600Kg of raw materials, in which iron rods are derusted, the rare earth materials are treated with oil-free, moisture-free and rust-free treatment, and the prepared raw materials are melted under the condition of medium frequency induction heating by vacuum melting (SC) , And finally obtain a sheet-shaped fast-quenched NdFeB alloy with columnar crystal structure.

[0060] Then, hydrogen is absorbed in a hydrogen crusher and crushed into millimeter-sized coarse particles. The medium crusher further crushes the particles, and then uses high-pressure nitrogen gas to grind uniformly micron-sized powder with an average particle size of 3.5-4.0μm.

[0061] Then, the jet mill powder is dehydrogenated and mechanically mixed through a dehydrogenation vessel, and the vacuum is reduced to below 0.1Pa. The dehydrog...

Embodiment 3

[0082] The verification with 50SH sintered NdFeB material, the raw material composition is shown in Table 11 below:

[0083] element

PrNd

Tb

Al

B

Cu

Co

Zr

Ga

Fe

wt%

28

2

0.1

0.91

0.12

1

0.17

0.2

67.5

[0084] First, according to the above formula, prepare 600Kg of raw materials, in which iron rods are derusted, the rare earth materials are treated with oil-free, moisture-free and rust-free treatment, and the prepared raw materials are melted under the condition of medium frequency induction heating by vacuum melting (SC) , And finally obtain a sheet-shaped fast-quenched NdFeB alloy with columnar crystal structure.

[0085] Then, hydrogen is absorbed in a hydrogen crusher and crushed into millimeter-sized coarse particles. The medium crusher further crushes the particles, and then grinds uniform micron-sized powder with high-pressure nitrogen through a jet mill. The average particle size of the powder is 3.5-3.8 μm.

[0086] Then the jet mill powder is dehydrogenated and mechanically m...

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Abstract

The invention provides neodymium-iron-boron magnet powder. A neodymium-rich phase in the powder granules generates neodymium hydride in a hydrogen absorption smashing stage; then in the subsequent air flow powder grinding stage, the powder granules obtain quite high resistance to oxidation, and a neodymium-iron-boron magnet with low rare earth content, low cost and high performance can be prepared more easily; the neodymium-iron-boron granules comprising the hydride are high in brittleness, and the air flow powder grinding efficiency is improved by 50% or even 100% compared with that of the conventional process; the prepared powder granule dimensions can be reduced to be smaller than 3[mu]m, which is a quite significant condition for preparing a sintered neodymium-iron-boron magnet with high coercivity and high thermal stability; the powder granules are subjected to dehydrogenation, so that the orientation degree of the powder granules in an orientation pressing process is improved, residual magnetism of the magnet is improved, generation of internal cracks of the magnet can be effectively suppressed, and the mechanical performance of the sintered neodymium-iron-boron magnet is improved; and by effectively combining the dehydrogenation process with a fine powder mixing process, the process is simplified, the powder production efficiency is improved and the cost is lowered.

Description

Technical field [0001] The invention belongs to the field of neodymium iron boron magnets, and particularly relates to a preparation method of neodymium iron boron magnet powder. Background technique [0002] NdFeB magnets have excellent magnetic properties. The production process includes batching, smelting, hydrogen explosion, powder making, orientation pressing, sintering, aging and post-processing. The purpose of powder milling is to crush large alloy ingots into powders of a certain size (3-5 microns). At present, there are two kinds of powder making methods commonly used, namely, ordinary steel ingot making and flake casting. Among them, flake ingot milling is prepared by using smelted flake ingots, undergoing hydrogen crushing and dehydrogenation treatment, jet milling, and fine powder mixing. [0003] In recent years, with the rapid expansion of NdFeB magnets in many fields, sintered NdFeB magnets are widely used in all aspects of life with their superior performance, suc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/0573H01F1/0576H01F1/0577H01F41/0266
Inventor 刘润海刘月玲
Owner 京磁材料科技股份有限公司
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