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NdFeB system sintered magnet

A technology for sintering magnets and substrates, which can be applied to magnetic objects, magnetic materials, inorganic materials, etc., and can solve problems such as slow diffusion.

Active Publication Date: 2014-05-14
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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  • NdFeB system sintered magnet
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  • NdFeB system sintered magnet

Examples

Experimental program
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Embodiment

[0044] For the method of manufacturing the NdFeB-based sintered magnets of this example and the comparative example, use figure 1 with figure 2 The flowchart is described.

[0045] Such as figure 1 As shown, the manufacturing method of the NdFeB-based sintered magnet of the present embodiment includes the following steps: Hydrogen crushing step (step A1): It is performed by storing hydrogen in a NdFeB-based alloy previously produced by a strip casting method. Coarse crushing; fine crushing step (step A2): Mix 0.05-0.1wt% of lubricants such as methyl octoate and other lubricants into the NdFeB-based alloy that has not been heated for dehydrogenation after hydrogen crushing in the hydrogen crushing step, using a jet mill The device is finely pulverized in a nitrogen stream, so that the median value (D50) of the particle size distribution measured by the laser diffraction method is below 3.2μm; the filling step (step A3): mix 0.05-0.15wt into the finely pulverized alloy powder % ...

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Abstract

A NdFeB system sintered magnet produced by the grain boundary diffusion method that has a high coercive force and squareness ratio with only a small decrease in the maximum energy product. The NdFeB system sintered magnet has a base material produced by orienting powder of a NdFeB system alloy and sintering the powder, with Dy and / or Tb (the "Dy and / or Tb" is hereinafter called RH) attached to and diffused from a surface of the base material through the grain boundary inside the base material by a grain boundary diffusion treatment, wherein the difference Cs-Cd3 between the RH content Cs (wt %) in the grain boundary reaching the surface to which RH is attached and the RH content Cd3 (wt %) in the grain boundary at a depth of 3 mm from the aforementioned attachment surface is equal to or smaller than 20 wt %.

Description

Technical field [0001] The present invention relates to a NdFeB-based sintered magnet manufactured by grain boundary diffusion treatment. Background technique [0002] NdFeB-based sintered magnets were discovered by Sagawa (one of the inventors) in 1982 and others. They have characteristics that significantly exceed those of the permanent magnets at that time. They can be composed of Nd (a kind of rare earth), iron, and boron. Advantages of manufacturing with cheap raw materials. Therefore, NdFeB-based sintered magnets are used in hybrid or electric vehicle drive motors, electric assisted vehicle motors, industrial motors, hard disks, etc. voice coil motors, high-end speakers, earphones, permanent magnet magnetic resonance diagnostic devices In various products. NdFeB series sintered magnets used in these applications require high coercivity H cJ , High maximum energy product (BH) max And high square ratio SQ. The squareness ratio SQ here is defined as follows: In the magneti...

Claims

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Application Information

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IPC IPC(8): H01F1/08B22F1/00B22F3/00C22C33/02H01F1/057H01F41/02
CPCC22C2202/02C22C33/02H01F41/0293C22C38/005H01F1/0577H01F1/08H01F1/057H01F41/02B22F1/05B22F3/10
Inventor 佐川真人沟口彻彦
Owner DAIDO STEEL CO LTD