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ndfeb sintered magnet

A technology of sintering magnets and substrates, which is applied in the direction of magnetic objects, magnetic materials, permanent magnets, etc., and can solve the problems of slow diffusion

Active Publication Date: 2016-01-20
DAIDO STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In contrast, since the main phase particles are still solid, the diffusion rate from the grain boundary into the main phase particles is slow

Method used

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Embodiment

[0045] For the method of manufacturing the NdFeB system sintered magnets of the present embodiment and comparative example, use figure 1 and figure 2 The flow chart is described.

[0046] Such as figure 1 As shown, the manufacturing method of the NdFeB-based sintered magnet of this embodiment includes the following steps: Hydrogen crushing step (step A1): roughening the NdFeB-based alloy by storing hydrogen in the NdFeB-based alloy prepared in advance by strip casting (StripCasting) method. Crushing; fine pulverization process (step A2): Mix 0.05 to 0.1 wt% of a lubricant such as methyl octanoate in the NdFeB-based alloy that has not been heated for dehydrogenation after hydrogen crushing in the hydrogen crushing process, and use a jet mill device Fine pulverization is carried out in a nitrogen gas flow, so that the median value of the particle size distribution measured by the laser diffraction method (D 50 ) below 3.2 μm; filling process (step A3): mix 0.05 to 0.15 wt ...

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PUM

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Abstract

The present invention provides a NdFeB-based sintered magnet manufactured by a grain boundary diffusion method, which has high coercive force and squareness ratio, and has little decrease in maximum energy product. The NdFeB-based sintered magnet of the present invention is characterized in that Dy and / or Tb (hereinafter, "Dy and / or Tb" will be referred to as "RH") adhering to the surface of the base material is diffused to the The NdFeB-based sintered magnet at the grain boundary inside the base material is manufactured by orienting and sintering the powder of the NdFeB-based alloy, and the RH concentration Ct (wt%) of the triple point of the grain boundary is the same as that of the grain boundary The number of grain boundary triple points where the difference Ct-Cw of the RH concentration Cw (wt %) of the two-grain boundary part where the triple points are connected is 4 wt% or less is 60% or more of the total number of grain boundary triple points.

Description

technical field [0001] The present invention relates to a NdFeB-based sintered magnet produced by grain boundary diffusion treatment. Background technique [0002] NdFeB-based sintered magnets were discovered by Sagawa (one of the inventors) in 1982. It has characteristics significantly surpassing those of permanent magnets at that time. It can be composed of Nd (a kind of rare earth), iron and boron. Advantages of cheap raw materials to manufacture. Therefore, NdFeB-based sintered magnets are used in driving motors for hybrid vehicles or electric vehicles, motors for electrically-assisted vehicles, industrial motors, voice coil motors such as hard disks, high-end speakers, earphones, and permanent magnet magnetic resonance diagnostic devices. and other products. NdFeB-based sintered magnets used in these applications are required to have high coercive force H cJ , High maximum energy product (BH) max and high rectangular ratio sq. The squareness ratio SQ here is define...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/08B22F1/00B22F3/00C22C33/02H01F1/057H01F41/02
CPCC22C2202/02H01F1/0577H01F41/0293C22C33/0278C22C38/00H01F1/08H01F1/057C22C33/02H01F7/02H01F1/0536B22F3/10
Inventor 佐川真人沟口彻彦
Owner DAIDO STEEL CO LTD