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Method for improving coercive force of neodymium-iron-boron magnet through efficient diffusion

A technology of NdFeB and coercive force, which is applied in the field of NdFeB magnet preparation, can solve the problems of waste of heavy rare earth elements, large amount of diffusing agent, over-strengthening of magnets, etc., so as to save usage, improve coercive force, and overall The effect of performance improvement

Pending Publication Date: 2021-10-15
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, simply coating a layer of uniform diffusion source will cause excessive strengthening of some parts of the magnet, resulting in unnecessary waste of heavy rare earth elements
[0006] In summary, the current grain boundary diffusion process still has the problem that the amount of diffusing agent is too large or not fully utilized.

Method used

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  • Method for improving coercive force of neodymium-iron-boron magnet through efficient diffusion
  • Method for improving coercive force of neodymium-iron-boron magnet through efficient diffusion
  • Method for improving coercive force of neodymium-iron-boron magnet through efficient diffusion

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] In this example, high coercive force NdFeB magnets are prepared by Pr-Tb-Al-Cu diffusion:

[0047] (1) Preparation of heavy rare earth-containing Pr by arc melting 42.26 Tb 47.67 Al 4.63 Cu 5.44 (wt%) alloy ingot.

[0048] (2) Remelting and spray-casting the alloy ingots obtained in step (1) respectively to obtain corresponding alloy strips.

[0049] (3) Coarsely crushing the alloy strip obtained in step (2) to obtain powder passing through a 60-mesh sieve.

[0050] (4) Mix the alloy powder obtained in step (3) with an organic binder (PVA glue) to obtain a diffusing agent.

[0051] (5) Use a 52M sintered NdFeB magnet as the diffusion substrate, cut into a cuboid sample by wire cutting, the size is 7×7×12mm, and the 12mm thickness direction is the easy axis (c axis) direction. After polishing it to a mirror surface, it was ultrasonically cleaned in acetone and absolute ethanol for 15 min.

[0052] (6) Apply the diffusing agent obtained in step (4) to the edge of t...

Embodiment 2

[0056] In this example, high coercive force NdFeB magnets are prepared by Tb-Al-Cu diffusion:

[0057] (1) Preparation of heavy rare earth-containing Tb by arc melting 90.45 Al 4.39 Cu 5.16 Alloy ingots.

[0058] (2) Remelting and spray-casting the alloy ingots obtained in step (1) respectively to obtain corresponding alloy strips.

[0059] (3) Coarsely crushing the alloy strip obtained in step (2) to obtain powder passing through a 60-mesh sieve.

[0060] (4) Mix the alloy powder obtained in step (3) with an organic binder (PVA glue) to obtain a diffusing agent.

[0061] (5) Use a 52M sintered NdFeB magnet as the diffusion substrate, cut into a cuboid sample by wire cutting, the size is 7×7×12mm, and the direction of the thickness of 12mm is the c-axis direction. After polishing it to a mirror surface, it was ultrasonically cleaned in acetone and absolute ethanol for 15 min.

[0062] (6) Spray the diffusion agent obtained in step (4) on the edge of the magnet obtained i...

Embodiment 3

[0066] In this example, high coercive force NdFeB magnets are prepared by Pr-Tb-Al-Cu diffusion:

[0067] (1) Preparation of heavy rare earth-containing Pr by arc melting 42.26 Tb 47.67 Al 4.63 Cu 5.44 (wt%) alloy ingot.

[0068] (2) Remelting and spray-casting the alloy ingots obtained in step (1) respectively to obtain corresponding alloy strips.

[0069] (3) Coarsely crushing the alloy strip obtained in step (2) to obtain powder passing through a 60-mesh sieve.

[0070] (4) Mix the alloy powder obtained in step (3) with an organic binder (PVA glue) to obtain a diffusing agent.

[0071] (5) Use N50 sintered NdFeB magnets as the diffusion substrate, and cut them into special-shaped samples by wire cutting, with dimensions such as image 3 As shown, the 10mm thickness direction is the c-axis direction. After polishing it to a mirror surface, it was ultrasonically cleaned in acetone and absolute ethanol for 15 min.

[0072] (6) Apply the diffusion agent obtained in step...

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Abstract

The invention discloses a method for improving coercive force of a neodymium-iron-boron magnet through efficient diffusion. The grain boundary diffusant containing heavy rare earth, light rare earth or not containing rare earth is coated on the edge or the edge and the periphery of the edge of the neodymium-iron-boron magnet for diffusion heat treatment, so that the coercivity of the magnet can be remarkably improved. Compared with surface overall coating grain boundary diffusion, the method has the advantages that the use amount of the diffusant is obviously reduced, and the loss of residual magnetism of the magnet is reduced; and compared with a traditional c-surface diffusion magnet, under the condition that the thickness of the magnet is large, the obtained magnet has higher coercive force and magnetic energy product. In addition, by adjusting the coating area of the corner diffusant, the coercive force of the magnet can be improved to different degrees, and great flexibility is achieved. According to the method disclosed by the invention, the corner part with weaker demagnetization resistance in the magnet is strengthened, so that the coercive force of the magnet is improved, the dosage of the diffusant is obviously reduced, and the extreme application of heavy rare earth elements is realized.

Description

technical field [0001] The invention belongs to the technical field of NdFeB magnet preparation, and in particular relates to a method for efficiently diffusing to improve the coercive force of NdFeB magnets. Background technique [0002] NdFeB rare earth permanent magnets have excellent hard magnetic properties and are widely used in new energy vehicles, intelligent communications and wind power generation. Since the 21st century, the development of technology has put forward higher requirements for the coercive force and other properties of NdFeB magnets. During the service of NdFeB permanent magnet motors, NdFeB magnets need to work stably at high temperatures (200°C), which requires NdFeB magnets to have high remanence, coercive force and maximum magnetic energy product at the same time. However, the hard magnetic main phase Nd 2 Fe 14 The Curie temperature of B is low (312°C), and the anisotropy field is highly sensitive to temperature, making the magnet extremely ea...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/057H01F41/02
Inventor 刘仲武宋文玥何家毅周帮余红雅钟喜春
Owner SOUTH CHINA UNIV OF TECH
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