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Method for preparing sintered NdFeB magnet

A technology of NdFeB and magnets, which is applied in the direction of magnetic objects, magnetic materials, inorganic materials, etc., can solve the problems of difficulty in obtaining nano-scale heavy rare earth powder, unsuitable for large-scale production, and inability to effectively control the distribution of heavy rare earths. Improving magnetic properties, controlling the microstructure of magnets, and improving the utilization rate of heavy rare earths

Active Publication Date: 2017-03-15
NINGBO KONIT IND +1
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

However, nanoscale heavy rare earth powders are difficult to obtain, and can only be obtained in a very small amount in the laboratory, which is not suitable for large-scale production
In addition, none of the methods disclosed in the above documents can effectively control the distribution of heavy rare earths in the magnet, and most of the heavy rare earths still enter the interior of the main phase grains, which cannot effectively utilize the heavy rare earths.

Method used

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  • Method for preparing sintered NdFeB magnet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Alloy Dy Obtained by Vacuum Induction Melting 50 (Fe 0.50 co 0.25 Cu 0.10 Al 0.15 ) 47 Zn 3 . Then by the hydrogen fragmentation method, a coarse powder of the alloy is obtained. Then use the ball milling method to grind the coarse powder into a powder with an average particle size of less than 3mm. Add the powder to the NdFeB Nd obtained by the hydrogen cracking method in a certain proportion 30 co 1.2 Al 0.2 Cu 0.1 B 1.0 Fe bal of coarse powder. The two powders were thoroughly mixed to obtain a mixed powder, and the mixed powder was heat-treated at 500° C. for 3 hours in a sealed container. After the mixed powder is cooled, it is ground into a fine powder with a jet mill. The fine powder is molded in a sealed system protected by nitrogen to obtain molded parts. The molding was sintered at 1000°C for 7 hours, and aged at 450°C for 5 hours. Finally, a sintered NdFeB magnet with the following magnetic properties was obtained: Br=12.3kGs, Hcj=30kOe at roo...

Embodiment 2

[0017] Alloy Tb Obtained by Vacuum Induction Melting 50 (Fe 0.50 co 0.25 Cu 0.10 Al 0.15 ) 47 Zn 3 . Then by the hydrogen fragmentation method, a coarse powder of the alloy is obtained. Then use the ball milling method to grind the coarse powder into a powder with an average particle size of less than 3mm. Add the powder to the NdFeB Nd obtained by the hydrogen cracking method in a certain proportion 30 co 1.2 Al 0.2 Cu 0.1 B 1.0 Fe bal of coarse powder. The two powders were thoroughly mixed to obtain a mixed powder, and the mixed powder was heat-treated at 500° C. for 3 hours in a sealed container. After the mixed powder is cooled, it is ground into a fine powder with a jet mill. The fine powder is molded in a sealed system protected by nitrogen to obtain molded parts. Sinter the molding at 1000°C for 5 hours, and then age at 450°C for 5 hours. Finally, a sintered NdFeB magnet with the following magnetic properties was obtained: Br=12.3kGs, Hcj=38kOe at room ...

Embodiment 3

[0019] Alloy Ho was Obtained by Vacuum Induction Melting 50 (Fe 0.50 co 0.25 Cu 0.10 Al 0.15 ) 47 Zn 3 . Then by the hydrogen fragmentation method, a coarse powder of the alloy is obtained. Then use the ball milling method to grind the coarse powder into a powder with an average particle size of less than 3mm. Add the powder to the NdFeB Nd obtained by the hydrogen cracking method in a certain proportion 30 co 1.2 Al 0.2 Cu 0.1 B 1.0 Fe bal of coarse powder. The two powders were thoroughly mixed to obtain a mixed powder, and the mixed powder was heat-treated at 500° C. for 3 hours in a sealed container. After the mixed powder is cooled, it is ground into a fine powder with a jet mill. The fine powder is molded in a sealed system protected by nitrogen to obtain molded parts. The molding was sintered at 1000°C for 7 hours, and aged at 450°C for 5 hours. Finally, a sintered NdFeB magnet with the following magnetic properties was obtained: Br=11.0kGs, Hcj=17kOe at...

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Abstract

The invention provides a method for preparing a sintered neodymium-iron-boron magnet. The method comprises the following steps: (a), obtaining an alloy HREx (Fe0.50Co0.25Cu0.10Al0.15)zZny, wherein HRE is Dy, Tb and / or Ho, and x+y+z is equal to 100; (b), obtaining coarse powder of the alloy; (c), grinding the coarse powder into powder with mean grain size less than 3mm; (d), adding the powder into neodymium-iron-boron coarse powder according to a certain proportion; (e), sufficiently and uniformly mixing the powder with the neodymium-iron-boron coarse powder to obtain mixed powder, and thermally treating the mixed powder in a sealed container; (f), grinding the mixed powder into fine powder after the mixed powder is cooled; (g), forming the fine powder in a sealing system with nitrogen gas protection to obtain a formed piece; and (h), sintering the formed piece, and then, carrying out ageing. The method disclosed by the invention can be used for lowering usage amount of heavy rare earth and is applicable to large-scale production of the neodymium-iron-boron magnet with excellent large-dimension performance.

Description

technical field [0001] The invention relates to a method for preparing a sintered NdFeB magnet. Background technique [0002] The remanence and energy product of the currently known sintered NdFeB are close to 95% of the theoretical value. Japan's Neomax Corporation announced that it has developed a sintered NdFeB magnet with the highest magnetic energy product of 59.5MGOes. The German VAC company reported that it has developed a magnet with the highest magnetic energy product of 56.7MGOes. my country's Yantai Zhenghai Magnetic Materials Co., Ltd. announced that it has prepared a magnet with the highest energy product of 56MGOes. However, the coercive force of the currently known sintered NdFeB is still only about 55% of the theoretical value. Among the magnet products available on the market, the magnet products with Hcj(kOe)+(BH)max(MGOe)>60 are called high magnetic performance magnets. A few domestic manufacturers can produce sintered NdFeB magnets with Hcj(kOe)+(B...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/00C22C33/02B22F9/04B22F3/16H01F1/057H01F1/08H01F41/02
Inventor 李正朱小矿钮萼王惠新韦立立
Owner NINGBO KONIT IND
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