Method for using magnetic steel of waste permanent magnet motor to prepare high-performance regenerated sintered neodymium iron boron (NdFeB) magnet

A technology of permanent magnet motors and rare earth permanent magnet motors, which is applied in the fields of magnetic objects, magnetic materials, inductors/transformers/magnets, etc., and can solve the problems of reduced maximum magnetic energy product of magnets, large volume fraction of neodymium-rich phase, and adverse effects on magnet performance, etc. problem, achieve the effect of recovering coercive force, repairing boundary defects, and good powder mixing effect

Inactive Publication Date: 2014-09-10
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Under the premise of achieving effective magnetic isolation of the main phase grains, if the size of the rare earth powder particles is too large, the volume fraction of the neodymium-rich phase in the magnet will be too large, and the remanence and maximum energy product of the magnet will decrease; if the rare earth powder particles If the size is too small, agglomeration will occur, which will also adversely affect the performance of the magnet

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) The magnet steel composition of waste rare earth permanent magnet motor is Nd 22.5 Dy 0.8 PR 7.1 Fe 67.8 co 0.7 Cu 0.1 B 1 . Place the scrap NdFeB magnets from which the coating has been removed in 5% nitric acid alcohol for 10 seconds, then clean them in alcohol solution and blow dry. Put the scrap magnetic steel in a vacuum tube furnace, carry out 150 ℃, 0.1MPa hydrogen pressure hydrogen absorption for 3 hours, 600 ℃, 1×10 -3 Pa was dehydrogenated for 10 hours to obtain NdFeB hydrogen explosion powder.

[0025] (2) The NdFeB magnetic powder is crushed to 3 microns by jet milling process.

[0026] (3) NdH nanopowders with an average particle size of 100 nanometers were prepared by physical vapor deposition technology.

[0027] (4) adding the neodymium hydride metal nano powder obtained in step (3) to the NdFeB raw material powder of step (2), the addition ratio of the neodymium hydride nano powder is 2% of the weight of the NdFeB raw material powder, and t...

Embodiment 2

[0052] (1) The magnet steel composition of waste rare earth permanent magnet motor is Nd 25.4 Dy 5 Fe 67.2 co 1.1 Cu 0.2 al 0.1 B 1 . Place the scrap NdFeB magnets from which the coating has been removed in 5% nitric acid alcohol for 10 seconds, then clean them in alcohol solution and blow dry. Put the scrap magnetic steel in a vacuum tube furnace, carry out 150 ℃, 0.1MPa hydrogen pressure hydrogen absorption for 3 hours, 600 ℃, 1×10 -3 Pa was dehydrogenated for 10 hours to obtain NdFeB hydrogen explosion powder.

[0053] (2) The NdFeB magnetic powder is crushed to 3 microns by jet milling process.

[0054] (3) NdH nanopowders with an average particle size of 500 nm were prepared by physical vapor deposition technology.

[0055] (4) adding the neodymium hydride metal nano powder obtained in step (3) to the NdFeB raw material powder of step (2), the addition ratio of the neodymium hydride nano powder is 4% of the weight of the NdFeB raw material powder, and the two pow...

Embodiment 3

[0080] (1) The magnet steel composition of waste rare earth permanent magnet motor is Nd 25.4 Dy 5 Fe 67.2 co 1.1 Cu 0.2 al 0.1 B 1 . Place the scrap NdFeB magnets from which the coating has been removed in 5% nitric acid alcohol for 10 seconds, then clean them in alcohol solution and blow dry. Put the scrap magnetic steel in a vacuum tube furnace, carry out 150 ℃, 0.1MPa hydrogen pressure hydrogen absorption for 3 hours, 600 ℃, 1×10 -3 Pa was dehydrogenated for 10 hours to obtain NdFeB hydrogen explosion powder.

[0081] (2) The NdFeB magnetic powder is crushed to 3 microns by jet milling process.

[0082] (3) NdH nanopowders with an average particle size of 300 nm were prepared by physical vapor deposition technology.

[0083] (4) adding the neodymium hydride metal nano powder obtained in step (3) to the NdFeB raw material powder of step (2), the addition ratio of the neodymium hydride nano powder is 3% of the weight of the NdFeB raw material powder, and the two pow...

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Abstract

The invention relates to a method for using magnetic steel of a waste permanent magnet motor to prepare a high-coercivity regenerated sintered neodymium iron boron (NdFeB) magnet and belongs to the technical field of magnetic materials. The rare earth dysprosium hydride nano powder doping technology is used to regenerate the magnetic steel of the waste rare earth permanent magnet motor so as to prepare the high-coercivity regenerated sintered NdFeB permanent magnet. The method includes: using hydrogen explosion and air flow milling to prepare NdFeB powder; using the physical gas phase deposition technology to prepare dysprosium hydride nano powder; mixing the two kinds of powder, and performing magnetic field orientation and compression moulding; performing dehydrogenation, sintering and thermal treatment on the compressed base at different temperatures to obtain the sintered magnet. The method has the advantages that the coercivity of the regenerated magnet can be higher than that of the original magnetic steel, and the residual magnetism and magnetic energy product of the regenerated magnet are close to those of the original magnetic steel, and the method is short in process flow, low in cost and energy consumption and resource saving.

Description

technical field [0001] The invention relates to a new technology of dismantling waste permanent magnet motor magnets as the main raw material and using the method of doping and sintering neodymium hydride nanoparticles to prepare high-performance regenerative sintered NdFeB magnets. The invention can realize waste rare earth permanent magnet motor neodymium The high-value reuse of iron-boron magnets belongs to the technical field of magnetic materials. Background technique [0002] In the past two decades, with the rapid development of my country's economy, rare earth resources have been decreasing and environmental pollution has become increasingly serious. The development space and potential of rare earth secondary resource recovery in my country are huge, but there are few researches on the recovery and reuse of rare earth resources. Among them, the low-value recycling and reuse of NdFeB waste with large output and high added value has become the current top priority. A...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02H01F1/057B22F9/04B22F3/16
Inventor 岳明刘卫强季维骁李超张东涛
Owner BEIJING UNIV OF TECH
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