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Method for using bulk sintered neodymium iron boron (NdFeB) machining waste to prepare high-performance regenerated NdFeB magnet

A high coercivity, NdFeB technology, used in magnetic objects, inductor/transformer/magnet manufacturing, magnetic materials, etc., can solve the reduction of the maximum magnetic energy product of the magnet, the adverse effect of the magnet performance, and the large volume fraction of the Nd-rich phase, etc. problems, to achieve the effect of restoring coercivity, 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

[0022] (1) The composition of bulk sintered NdFeB processing waste is Nd 22.3 Dy 0.6 PR 7.5 Fe 67.8 co 0.7 Cu 0.1 B 1 . Put the NdFeB waste in 5% nitric acid alcohol for 10 seconds, wash it in the alcohol solution, and blow dry. Put the waste in a vacuum tube furnace, carry out 150°C, 0.1MPa hydrogen pressure hydrogen absorption for 3 hours, 600°C, 1×10 -3 Pa was dehydrogenated for 10 hours to obtain NdFeB hydrogen explosion powder.

[0023] (2) The NdFeB magnetic powder is crushed to 3 microns by jet milling process.

[0024] (3) Preparing praseodymium hydride nanopowder with an average particle size of 100 nanometers by using physical vapor deposition technology.

[0025] (4) adding the praseodymium hydride metal nano powder obtained in step (3) to the NdFeB raw material powder in step (2), the addition ratio of the praseodymium hydride nano powder is 2% of the weight of the NdFeB raw material powder, and mixing the two powders evenly;

[0026] (5) Orienting and pr...

Embodiment 2

[0050] (1) The composition of bulk sintered NdFeB processing waste is Nd 25.7 Dy 5 Fe 67.2 co 0.8 Cu 0.2 Al 0.1 B 1 . Put the NdFeB waste in 5% nitric acid alcohol for 10 seconds, wash it in the alcohol solution, and blow dry. Put the waste in a vacuum tube furnace, carry out 150°C, 0.1MPa hydrogen pressure hydrogen absorption for 3 hours, 600°C, 1×10 -3 Pa was dehydrogenated for 10 hours to obtain NdFeB hydrogen explosion powder.

[0051] (2) The NdFeB magnetic powder is crushed to 3 microns by jet milling process.

[0052] (3) Preparing praseodymium hydride nanopowder with an average particle size of 500 nanometers by physical vapor deposition technology.

[0053] (4) adding the praseodymium hydride metal nano powder obtained in step (3) to the NdFeB raw material powder of step (2), the addition ratio of the praseodymium hydride nano powder is 4% of the weight of the NdFeB raw material powder, and the two powders are mixed uniformly;

[0054] (5) Orienting and pres...

Embodiment 3

[0078] (1) The composition of bulk sintered NdFeB processing waste is Nd 25.7 Dy 5 Fe 67.2 co 0.8 Cu 0.2 Al 0.1 B 1 . Put the NdFeB waste in 5% nitric acid alcohol for 10 seconds, wash it in the alcohol solution, and blow dry. Put the waste in a vacuum tube furnace, carry out 150°C, 0.1MPa hydrogen pressure hydrogen absorption for 3 hours, 600°C, 1×10 -3 Pa was dehydrogenated for 10 hours to obtain NdFeB hydrogen explosion powder.

[0079] (2) The NdFeB magnetic powder is crushed to 3 microns by jet milling process.

[0080] (3) Preparing praseodymium hydride nanopowder with an average particle size of 300 nanometers by physical vapor deposition technology.

[0081] (4) adding the praseodymium hydride metal nano powder obtained in step (3) to the NdFeB raw material powder of step (2), the addition ratio of the praseodymium hydride nano powder is 3% of the NdFeB raw material powder weight, and the two powders are mixed evenly;

[0082] (5) Orienting and pressing the u...

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Abstract

The invention relates to a method for using bulk sintered neodymium iron boron (NdFeB) machining waste to prepare a high-coercivity regenerated NdFeB magnet and belongs to the technical field of magnetic materials. The rare earth praseodymium hydride nano powder doping technology is used to regenerate the sintered NdFeB machining waste so as to prepare the high-performance 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 praseodymium 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 various magnetic performances of the regenerated magnet prepared by the method can restore to the level an original magnet, and the coercivity of the regenerated magnet is higher than that of the original magnet, 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 for preparing high-performance and high-coercivity regenerative sintered NdFeB magnets by using sintered NdFeB processing waste as the main raw material and using praseodymium hydride nano-particle doping and sintering. The invention is used for recycling sintered NdFeB magnets The leftover material belongs to the technical field of magnetic materials. Background technique [0002] Sintered NdFeB is currently the most magnetic permanent magnet material. It is widely used in hard disk drives, electric vehicles (EV), wind power generation, consumer electronics and many other fields. It has become an irreplaceable basic material for high-tech power, driving With the development of all walks of life. The output of NdFeB has also increased rapidly with the increase of demand, especially after 2000, its average annual growth rate is about 26.2%. However, due to the high brittleness of sintered NdFeB, 20-30% of scra...

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 刘卫强岳明李超季维骁张东涛
Owner BEIJING UNIV OF TECH
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