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NdFeB system sintered magnet

A sintered magnet, total volume technology, applied in the direction of magnetic objects, magnetic materials, permanent magnets, etc., can solve problems such as slow diffusion

Active Publication Date: 2014-01-08
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

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Embodiment

[0045] 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.

[0046] 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 of the particle size distribution measured by the laser diffraction method (D 50 ) Reach below 3.2μm; filling process (step A3): mix 0.05-0.15wt% of lubricants such as methyl laurate i...

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Abstract

To provide a NdFeB system sintered magnet that is manufactured using a grain-boundary diffusion process, has high coercivity and squareness ratio, and exhibits little in the way of decreases in maximum energy product. This NdFeB system sintered magnet is obtained as follows: dysprosium and / or terbium (hereinafter "dysprosium and / or terbium" is referred to as "RH") attached to the surface of a substrate manufactured by aligning and sintering a powdered NdFeB alloy is diffused along grain boundaries inside said substrate by means of a grain-boundary diffusion process. This NdFeB system sintered magnet is characterized in that for at least 60% of grain-boundary triple junctions therein, the difference (Ct - Cw) between the RH concentration (Ct) (wt.%) at that grain-boundary triple junction and the RH concentration (Cw) (wt.%) along two-grain grain boundaries connected to that grain-boundary triple junction is at most 4 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
CPCH01F41/02H01F7/02H01F1/057H01F41/0293H01F1/0536H01F1/08C22C33/0278C22C2202/02H01F1/0577C22C38/00C22C33/02B22F3/10
Inventor 佐川真人沟口彻彦
Owner DAIDO STEEL CO LTD