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Grain boundary diffusion method for simultaneously improving corrosion resistance and coercive force of mixed rare earth permanent magnet material through 1: 2 phase

A technology of grain boundary diffusion and rare earth mixing, which is applied in the manufacture of magnetic materials, magnetic objects, inductors/transformers/magnets, etc., can solve the problems of intensified electrochemical corrosion and corrosion resistance deterioration, and achieve the effect of simple process and cost reduction

Pending Publication Date: 2022-07-22
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the traditional grain boundary reconstruction or grain boundary diffusion method introduces more rare-earth-rich grain boundary phases to isolate the short-range magnetic exchange coupling of adjacent ferromagnetic main phase grains, thereby increasing the coercive force; Corrosion channel, exacerbated electrochemical corrosion, severely deteriorated corrosion resistance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] 1) The initial sintered magnet is prepared by powder metallurgy process, and the composition is (Ce 0.4 Nd 0.38 La 0.1 Pr 0.05 Ho 0.07 ) 30.8 Fe bal (Al 0.35 Ga 0.15 Cu 0.25 Nb 0.25 ) 1.5 B 1.0 ;

[0023] 2) The grain boundary diffusion source is supported on the surface of the initial sintered magnet by the method of bonding with a binder, and the composition is (Nd) in terms of mass percentage. 0.6 Pr 0.4 ) 0.75 Fe 0.15 Cu 0.1 ;

[0024] 3) Carry out grain boundary diffusion heat treatment, the diffusion temperature is controlled at 900°C, and the diffusion time is controlled at 5h; then tempering is performed, the tempering temperature is controlled at 480°C, and the tempering time is controlled at 3h;

[0025] 4) Finally, a mixed rare earth permanent magnet material with a high 1:2 phase content is obtained, and the corrosion resistance and coercivity are simultaneously improved. The slow-scan XRD refinement results show that the 1:2 phase content ...

Embodiment 2

[0029] 1) The initial sintered magnet is prepared by powder metallurgy process, and the composition is (Ce 0.3 Nd 0.54 Y 0.1 Gd 0.06 ) 30.5 Fe bal (Co 0.35 Al 0.25 Cu 0.2 Si 0.05 Zr 0.15 ) 1.3 B 1.05 ;

[0030] 2) The grain boundary diffusion source is supported on the surface of the initial sintered magnet by the method of direct physical contact, in terms of mass percentage, the composition is (Pr 0.85 La 0.1 Dy 0.05 ) 0.8 Fe 0.14 Al 0.05 H 0.01 ;

[0031] 3) Carry out grain boundary diffusion heat treatment, the diffusion temperature is controlled at 800°C, and the diffusion time is controlled at 6h; then tempering is performed, the tempering temperature is controlled at 500°C, and the tempering time is controlled at 6h;

[0032]4) Finally, a mixed rare earth permanent magnet material with a high 1:2 phase content is obtained, and the corrosion resistance and coercivity are simultaneously improved. The slow-scan XRD refinement results show that the 1:2 p...

Embodiment 3

[0036] 1) The initial sintered magnet is prepared by powder metallurgy process, and the composition is (Ce 0.55 Nd 0.35 La 0.1 ) 31.2 Fe bal (Ga 0.35 Cu 0.25 Al 0.2 Zr 0.15 Nb 0.05 ) 2.0 B 0.95 ;

[0037] 2) Using the method of magnetron sputtering physical vapor deposition to load the grain boundary diffusion source on the surface of the initial sintered magnet, in terms of mass percentage, the composition is Pr 0.85 Co 0.15 ;

[0038] 3) Carry out grain boundary diffusion heat treatment, the diffusion temperature is controlled at 850°C, and the diffusion time is controlled at 3h;

[0039] 4) Finally, a mixed rare earth permanent magnet material with a high 1:2 phase content is obtained, and the corrosion resistance and coercivity are simultaneously improved. The slow-scan XRD refinement results show that the 1:2 phase content of the magnet is 12.5 wt.%. The mass loss of the magnet was 1.5 mg / cm after exposure for 96 h in a hot and humid environment (100% relat...

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Abstract

The invention discloses a grain boundary diffusion method for simultaneously improving the corrosion resistance and coercive force of a mixed rare earth permanent magnetic material through 1: 2 phases. After a Ce-rich mischmetal sintered permanent magnet is prepared by adopting a powder metallurgy process, a grain boundary diffusion alloy source is loaded on the surface of the magnet by adopting a vapor deposition, electroplating, direct physical contact or binder bonding method, and grain boundary diffusion heat treatment and tempering are carried out. The process is simple, the interaction effect and characteristic diffusion behavior of multi-element rare earth in the grain boundary diffusion process are fully utilized, the content of the 1: 2 phase in the magnet is increased, the composition and distribution of the 1: 2 phase are regulated and controlled, and the purpose of improving the corrosion resistance and coercive force of the mixed rare earth permanent magnet material at the same time is achieved. The key problem that the corrosion resistance and the coercive force of the rare earth permanent magnet material are difficult to synergistically improve for a long time is solved.

Description

technical field [0001] The invention relates to the field of rare earth permanent magnet materials, in particular to a grain boundary diffusion method for simultaneously improving the corrosion resistance and coercive force of mixed rare earth permanent magnet materials through a 1:2 phase. Background technique [0002] High-abundance rare earth Ce is cheap and easy to form stable Ce 2 Fe 14 The B tetragonal phase is expected to replace a large number of scarce rare earth elements such as Nd / Pr / Dy / Tb for the production of low-cost Ce-rich magnets. A lot of research progress has been made in recent years. Based on the development of Ce-rich magnets, Ce / La / Y and other mixed rare earth permanent magnet materials can further reduce the cost of raw materials, realize the efficient and high-value application of high-abundance mixed rare earth resources, and promote the balanced utilization of rare earth resources. New research hotspots in the field of rare earth permanent magnet...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02H01F1/057
CPCH01F41/0293H01F1/0577B22F2003/248C22C33/0278C22C2202/02B22F2999/00B22F2003/241B22F2207/01B22F3/24B22F2301/355
Inventor 金佳莹王静桂阳龚晨陈望周良严密
Owner ZHEJIANG UNIV