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Grain boundary diffusion method for neodymium-iron-boron magnet

A grain boundary diffusion, NdFeB technology, applied in magnetic objects, magnetic materials, inductance/transformer/magnet manufacturing, etc., can solve the problem of incremental discount of coercive force, reduce remanence, improve uniformity, improve The effect of magnet coercivity

Active Publication Date: 2017-02-15
ZHEJIANG DONGYANG DMEGC RARE EARTH MAGNET CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method is easily restricted by the equipment conditions. Moreover, when the powder particle size is fine to a certain extent, its effect will be oxidized due to the increase in powder activity, which also leads to a greatly reduced coercive force increase.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Grain boundary powder Nd of low melting point rare earth alloy 70 Cu 30 It is prepared by rare earth alloy powder metallurgy process (quick solidification-hydrogen breaking-high energy ball milling), and the average powder particle size is 2.5μm. 1wt% Nd 70 Cu 30 Incorporation (PrNd) 30 Fe bal Al 0.1 Cu 0.1 Zr 0.1 B main phase alloy powder, mixed evenly, oriented in a magnetic field to form a rough magnet, put into a vacuum sintering furnace for sintering at 1050°C, and tempering at 900°C+500°C for 4 hours.

Embodiment 2

[0027] The composition ratio of the main phase alloy is (PrNd) 30 Fe bal Al 0.1 Cu 0.1 Zr 0.1 B, made by quick-setting process, followed by hydrogen breaking and jet milling, the average powder particle size is 3.5μm. Orientation molding in a magnetic field to make a rough magnet, put it into a vacuum sintering furnace and sinter at 1050°C, process it into a sample column with a thickness of 1.6cm, and electrophoresis coat a layer of low melting point rare earth alloy Nd on the surface of the sintered rough magnet. 70 Cu 30 , after vacuum drying, put them in a sintering furnace for tempering heat treatment at 900°C+500°C, and the tempering time is 4h.

Embodiment 3

[0029] Grain boundary powder Nd of low melting point rare earth alloy 70 Cu 30 It is prepared by rare earth alloy powder metallurgy process (quick solidification-hydrogen breaking-high energy ball milling), and the average powder particle size is 2.5μm. 1wt% Nd 70 Cu 30 Incorporation (PrNd) 30 Fe bal Al 0.1 Cu 0.1 Zr 0.1 B main phase alloy powder, mixed evenly, oriented in a magnetic field to form a rough magnet, put into a vacuum sintering furnace and sintered at 1050°C respectively, processed into a sample column with a thickness of 1.6cm, electrophoretic coating on the surface of the sintered rough magnet Coated with a layer of low melting point rare earth alloy Nd 70 Cu 30 , after vacuum drying, put them in a sintering furnace for tempering heat treatment at 900°C+500°C, and the tempering time is 4h.

[0030] The comparison of magnetic properties of the magnets prepared in Comparative Example 1, Example 1, Example 2, and Example 3 is shown in Table 1.

[0031] T...

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PUM

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Abstract

The invention discloses a grain boundary diffusion method for a neodymium-iron-boron magnet. The method comprises the following specific steps: preparing main-phase alloy powders through the neodymium-iron-boron powder metallurgy technique; preparing grain boundary powders of a low-melting-point rare earth alloy through the rare earth alloy powder metallurgy technique; evenly mixing the main-phase alloy powders and the grain boundary powders of the low-melting-point rare earth alloy according to a certain proportion; carrying out orienting compression in a magnetic field to prepare a neodymium-iron-boron magnet blank, and carrying out sintering of the neodymium-iron-boron magnet blank for 3 to 5 hours at a temperature of 1,000 to 1,100 DEG C, so as to prepare a sintered neodymium-iron-boron magnet; coating the magnet surface with a low-melting-point rare earth alloy layer through electrophoresis; and placing the magnet in a vacuum sintering furnace for secondary tempering heat treatment. The method provided by the invention has the beneficial effects that the coercivity of the magnet is improved while the residual magnetism is hardly reduced; the diffusion depth of heavy rare earth elements in the magnet can be improved; the uniformity of the magnet after the diffusion is improved; and the method is applicable for batch production.

Description

technical field [0001] The invention relates to the related technical field of rare earth permanent magnet materials, in particular to a method for the grain boundary diffusion of NdFeB magnets. Background technique [0002] NdFeB permanent magnet materials are widely used in the fields of computers, wind power generation, aerospace and equipment automation because of their excellent magnetic properties. They are currently the fastest growing permanent magnet materials with the best market prospects. , the key to lightweight and high power. [0003] The temperature stability of sintered NdFeB magnets is poor, and the working temperature is usually lower than 100 ° C, which greatly limits its application in electric vehicles and hybrid vehicles. In order to meet the high temperature application of NdFeB magnets, it is necessary to increase the room temperature coercive force of the magnets. Therefore, how to improve the coercive force of the magnet has become a key issue of...

Claims

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Application Information

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IPC IPC(8): H01F41/02H01F1/057C25D13/02B22F3/24
CPCB22F3/24B22F2003/248C25D13/02H01F1/0575H01F41/0293
Inventor 章晓峰韩相华洪群峰郝忠彬李润锋孙永阳王占洲
Owner ZHEJIANG DONGYANG DMEGC RARE EARTH MAGNET CO LTD
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