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Preparation method for neodymium-iron-boron magnet powder

A technology of neodymium iron boron and magnets, which is 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 achieve increased remanence, increased orientation, high heat The effect of stability

Active Publication Date: 2017-05-17
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 for neodymium-iron-boron magnet powder
  • Preparation method for neodymium-iron-boron magnet powder
  • Preparation method for neodymium-iron-boron magnet powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

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

[0033] element PrN Dy Al B Cu co Zr Ga Fe wt% 29 1 0.1 0.9 0.15 1.5 0.17 0.2 66.98

[0034] First, according to the above formula, 600Kg of raw materials are prepared, among which iron rods are derusted, rare earth materials are treated without oil, moisture and rust, and the prepared raw materials are melted under the condition of medium frequency induction heating by vacuum smelting (SC) , and finally obtain a sheet-shaped fast-quenching NdFeB alloy with a columnar crystal structure.

[0035] Then absorb hydrogen in the hydrogen furnace and crush it into millimeter-sized coarse particles. The secondary crusher further crushes the particles, and then passes through the jet mill with high-pressure nitrogen to grind out micron-sized powder with uniform particle size. The average particle size of the powder is 4.0-4...

Embodiment 2

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

[0058] element PrN Dy Al B Cu co Zr Ga Fe wt% 27 4 0.1 0.9 0.15 1.5 0.17 0.25 65.93

[0059] First, according to the above formula, 600Kg of raw materials are prepared, among which iron rods are derusted, rare earth materials are treated without oil, moisture and rust, and the prepared raw materials are melted under the condition of medium frequency induction heating by vacuum smelting (SC) , and finally obtain a sheet-shaped fast-quenching NdFeB alloy with a columnar crystal structure.

[0060] Then absorb hydrogen in the hydrogen furnace and crush it into millimeter-sized coarse particles. The secondary crusher further crushes the particles, and then passes through the jet mill with high-pressure nitrogen to grind out micron-sized powder with uniform particle size. The average particle size of the powder is 3.5...

Embodiment 3

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

[0083] element PrN 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, 600Kg of raw materials are prepared, among which iron rods are derusted, rare earth materials are treated without oil, moisture and rust, and the prepared raw materials are melted under the condition of medium frequency induction heating by vacuum smelting (SC) , and finally obtain a sheet-shaped fast-quenching NdFeB alloy with a columnar crystal structure.

[0085] Then absorb hydrogen in the hydrogen furnace and crush it into millimeter-sized coarse particles. The secondary crusher further crushes the particles, and then passes through the jet mill with high-pressure nitrogen to grind out micron-sized powder with uniform particle size. The average particle size of the powder is 3.5-3...

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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 in particular 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 making is to break large alloy ingots into powder bodies of a certain size (3-5 microns). There are two commonly used milling methods at present, that is, ordinary steel ingot milling and scale casting ingot milling. Among them, flake ingot powder is prepared by using smelted flake ingot, hydrogen crushing and then 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 due to their superior performan...

Claims

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Application Information

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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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