Method for preparing sintered neodymium iron boron through grain boundary diffusion of heavy rare earth

A technology of grain boundary diffusion and neodymium iron boron, applied in the direction of magnetic materials, magnetic objects, electrical components, etc., can solve the problems of inability to fully exert the effect of heavy rare earth, limited permanent magnet effect, poor squareness, etc., and achieve the best use effect and Convenience, improving utilization efficiency, and avoiding the effect of unevenness

Active Publication Date: 2016-01-13
CHINALCO JINYUAN RARE EARTH
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  • Abstract
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Problems solved by technology

Japanese scholars first developed the model of grain boundary diffusion. Diffusion of heavy rare earths into magnets by coating and heat treatment shows that the coercive force and temperature resistance are greatly improved. The disadvantages are obvious, because only coated It is applied to the surface of the material, so its diffusion depth is only limited to the micron level, which leads to the fact that the process can only process thin sheet permanent magnet materials, and has limited effect on large rare earth permanent magnets; some domestic research institutions have studied the method of double

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  • Method for preparing sintered neodymium iron boron through grain boundary diffusion of heavy rare earth

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0020] Embodiment 1

[0021] Dy is added when the NdFeB alloy is smelted, where the amount of Dy accounts for 0.5% of the mass fraction of the NdFeB alloy; then it is pressed in a magnetic field press, sintered and aged in a vacuum sintering furnace. The sintering temperature of vacuum sintering is 1065°C and the sintering time is 4h. The aging is divided into two times, the first aging is kept at 920°C for 5h, and the second aging is kept at 470°C for 4h.

Example Embodiment

[0022] Embodiment 2

[0023] The iron-neodymium-boron alloy powder and Dy fluoride are mixed in a powder mixer for 30 minutes, where the amount of Dy fluoride accounts for 0.5% of the mass fraction of the amount of NdFeB alloy; then it is pressed into a shape in a magnetic field press and sintered in a vacuum Sintering and aging in a furnace, wherein the sintering temperature of the vacuum sintering is 1065°C, the sintering time is 4h, the aging is divided into two times, the first aging is kept at 920°C for 5h, and the second aging is at 470°C Incubate for 4h.

Example Embodiment

[0024] Embodiment 3

[0025] A method for preparing sintered neodymium iron boron by diffusing heavy rare earths at grain boundaries. The heavy rare earth materials are mixed with an organic solvent to form a suspension, which is dispersed into the neodymium iron boron alloy powder to obtain neodymium iron boron powder a, which is heated and cooled , After sieving, press molding, sintering and aging treatment.

[0026] Wherein, the preparation method of the suspension is as follows: first transfer 100 parts by weight of heavy rare earth substances and 5 parts by weight of ethanol to a ball mill to make a jelly, and the ball milling time is 2 hours, take it out and add 80 parts by weight of ethanol, Stir for 3 hours to obtain the suspension; wherein the heavy rare earth material is Dy fluoride; after mixing the heavy rare earth material with an organic solvent, place it in a ball mill for grinding, then add the organic solvent again and stir to make a heavy rare earth suspension Tu...

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Abstract

The invention provides a method for preparing sintered neodymium iron boron through grain boundary diffusion of heavy rare earth. The method comprises the steps that heavy rear earth matter and organic solvent are mixed to prepare turbid liquid; the turbid liquid is subjected to dispersion treatment in neodymium iron boron alloy powder, and neodymium iron boron powder is obtained; and after being heated, cooled and sieved, the neodymium iron boron powder is subjected to compression molding, sintering and aging treatment, and the sintered neodymium iron boron is obtained. According to the method, the heavy rear earth matter and the neodymium iron boron alloy powder are sintered, so that the heavy rear earth matter and the neodymium iron boron powder are mixed evenly, the preparation process is simple, the using amount of the heavy rear earth matter is small, and the utilization rate of the heavy rear earth matter is high; meanwhile, the coercivity and temperature resistance of the sintered neodymium iron boron are improved, and the consistency of properties of the sintered neodymium iron boron is guaranteed.

Description

technical field [0001] The invention relates to a processing technology for preparing sintered NdFeB by diffusing heavy rare earth in the grain boundary, especially improving the grain boundary diffusion process of sintered NdFeB, improving the composition of sintered NdFeB as a whole, and improving the coercive force and Process for temperature resistance. Background technique [0002] Sintered NdFeB is the most cost-effective permanent magnet material today, known as the "magnet king". Compared with other permanent magnets, the local temperature of sintered NdFeB is low, which is the main factor restricting its application in industry. In order to improve the temperature resistance of sintered NdFeB, people have tried various methods. Among the existing conclusions, the antiferromagnetic coupling characteristics of heavy rare earths can offset the low local temperature brought about by the ferromagnetic coupling of light rare earths. problem, but the stock of heavy rare ...

Claims

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Application Information

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IPC IPC(8): B22F1/00H01F1/057H01F1/08
Inventor 黄伟超甘家毅曾阳庆龙植枝李剑锋
Owner CHINALCO JINYUAN RARE EARTH
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