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Method for improving coercive force of sintered neodymium iron boron magnet

A neodymium-iron-boron and coercivity technology, which is applied in the field of preparation of neodymium-iron-boron magnets, can solve the problems of inability to achieve high remanence Br coercivity, increase the cost of magnets, reduce remanence and the maximum magnetic energy product, etc.

Inactive Publication Date: 2017-04-26
JINGCI NEW MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But at the same time, it will also bring some adverse consequences. The magnetic moments of Nd and Fe are in the same direction, while Dy / Tb and Fe are antiferromagnetically coupled, so the replacement of this element will cause the remanence of the magnet and the maximum magnetic energy product (BHmax ) is significantly reduced, and it will also increase the cost of the magnet
At present, the sintered NdFeB magnets produced by the traditional technology in China cannot achieve high remanence Br and high coercive force Hcj at the same time.

Method used

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  • Method for improving coercive force of sintered neodymium iron boron magnet

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Embodiment 1

[0042] Such as figure 1 As shown, the method for improving the coercive force of sintered NdFeB magnets described in the present invention comprises the following steps:

[0043] 1) Furnace alloy: sintered NdFeB magnets are made by traditional technology, and the alloy composition includes at least: the total amount of rare earth ΣRe: 29.7% in terms of mass fraction;

[0044] 2) Flour making: use the quick-setting sheet ingot process (Strip Casting) to make sheet ingots, columnar crystal ratio: ≥85%, sheet thickness: 0.1-0.5mm; cast the obtained NdFeB sheet into ingots , after hydrogen crushing and coarse crushing, the average particle size of the coarse powder: 50-200μm, the prepared NdFeB coarse powder is powdered by jet milling, the average particle size of the powder is 2.9μm,

[0045] 3) Orientation molding, sintering, tempering: Orientation magnetic field strength: 1.5T, sintering at 1045°C high temperature sintering, and then tempering at 520°C to make a rough. The ave...

Embodiment 2

[0052] The method for improving the coercive force of a sintered NdFeB magnet according to the present invention comprises the following steps:

[0053] 1) Prepare NdFeB alloy, wherein the raw materials include by mass fraction: the total amount of rare earth ΣRe: 30%, and the content of heavy rare earth Dy / Tb: 8%;

[0054] 2) Using the quick-setting flake ingot process to make flake ingots to obtain NdFeB flake ingots, wherein the proportion of columnar crystals is not less than 85%, and the thickness of the flakes is 0.1-0.5mm;

[0055] 3) The obtained NdFeB flakes are cast into ingots, and the NdFeB coarse powder is obtained by hydrogen crushing and coarse crushing. The average particle size of the coarse powder particles is 50-200 μm, and then the NdFeB powder is obtained by jet milling , the average particle size of the powder is 5μm, and then it is oriented and formed with an orientation magnetic field of 1.8T, then sintered at a high temperature of 1020-1060°C, and then...

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Abstract

The invention discloses a method for improving the coercive force of a sintered neodymium iron boron magnet. The method comprises the following steps: using a magnetron sputtering technology, and sputtering a rare-earth metal thin film with the thickness of 1 to 8 microns on the surface of a sintered neodymium iron boron magnet blank. A Dy / Tb thin film is formed on the surface of the magnet by using the magnetron sputtering technology, the Dy / Tb enters into a surface layer of Nd2Fe14B crystal particles through grain boundary diffusion seepage, and the anisotropy is strengthened, so that the coercive force of the magnet is greatly improved under the condition of guaranteeing that residual magnetism of the magnet is almost unchanged.

Description

technical field [0001] The invention relates to a preparation method of an NdFeB magnet. More specifically, the present invention relates to a method for increasing the coercive force of sintered NdFeB magnets. Background technique [0002] The traditional process to improve the coercive force (Hcj) of sintered NdFeB magnets is to directly add heavy rare earth metals Dy and Tb to the smelted alloy, replace Nd in NdFeB with Dy / Tb and other heavy rare earth elements, and Dy / Tb replace the main phase Nd 2 Fe 14 After adding Nd in B, the anisotropy of the new phase generated is higher than that of the original Nd 2 Fe 14 The B phase is large, so the coercive force Hcj of the sintered magnet can be significantly improved. But at the same time, it will also bring some adverse consequences. The magnetic moments of Nd and Fe are in the same direction, while Dy / Tb and Fe are antiferromagnetically coupled, so the replacement of this element will cause the remanence of the magnet ...

Claims

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Application Information

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IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/0573H01F1/0577H01F41/0293
Inventor 胡元磊
Owner JINGCI NEW MATERIAL CO LTD
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