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R-t-b permanent magnet

A R-T-B, permanent magnet technology, applied in the direction of magnetic objects, magnetic materials, inductors/transformers/magnet manufacturing, etc., can solve the problems of saturation magnetization reduction, magnetic flux density reduction, etc., and achieve excellent magnetic properties.

Active Publication Date: 2020-06-09
TDK CORPARATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when the addition amount of the heavy rare earth element is too large, the saturation magnetization (saturation magnetic flux density) of the R-T-B permanent magnet decreases, and the residual magnetic flux density also decreases.

Method used

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Embodiment

[0140] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these examples at all.

[0141]

[0142] The raw material alloy 1 is produced from the raw material metal by the strip casting method. By weighing the raw material metal, the composition of the raw material alloy 1 was adjusted so that the composition of the raw material alloy 1 after sintering was consistent with the composition of the magnet base material 1 in Table 1 below.

[0143] After hydrogen was occluded in the raw material alloy 1 at room temperature, the raw material alloy 1 was heated at 600° C. in an Ar atmosphere for 1 hour to dehydrogenate, thereby obtaining a raw material alloy powder. That is, hydrogen pulverization treatment is performed.

[0144] Zinc stearate was added to the raw material alloy powder as a grinding aid, and these raw materials were mixed with a conical mixer. The cont...

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Abstract

An R-T-B permanent magnet comprises rare-earth elements R, transition metal elements T, and boron B, wherein at least some of the rare-earth elements R is Nd and at least one of Tb and Dy; at least some of the transition metal elements T are Fe; the R-T-B permanent magnet comprises a plurality of main phase grains and grain boundary triple points each surrounded by the main phase grains; the grainboundary triple points comprise at least one of Nd and Pr, at least one of Tb and Dy, at least one of Fe and Co, and copper; the average contents of Nd, Pr, Tb, Dy, Fe, Co and Cu each (unit: atom %)are represented by [Nd], [Pr], [Tb], [Dy], [Fe], [Co] and [Cu]; ([Fe]+[Co]) / ([Nd]+[Pr]) is 2 or more and 5 or less; and [Cu] / ([Tb]+[Dy]) is 1 or more and 4 or less.

Description

technical field [0001] The present invention relates to R-T-B permanent magnets. Background technique [0002] R-T-B permanent magnets containing rare earth elements R (neodymium, etc.), transition metal elements T (iron, etc.), and boron B have excellent magnetic properties. As indexes representing the magnetic properties of the R-T-B permanent magnet, the residual magnetic flux density Br (residual magnetization) and the coercive force HcJ are generally used. [0003] The R-T-B permanent magnet is a nucleation type permanent magnet. By applying a magnetic field opposite to the magnetization direction to the nucleation-type permanent magnet, magnetization-reversed nuclei are easily generated in the vicinity of grain boundaries of a plurality of crystal grains (main phase grains) constituting the permanent magnet. Due to this magnetization reversal nucleus, the coercive force of the permanent magnet is reduced. [0004] In order to improve the coercive force of the R-T-B-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057
CPCH01F1/0571H01F1/0577C22C38/06C22C38/16C22C38/10C22C38/002C22C38/14C22C38/005H01F41/0293H01F1/057C22C2202/02
Inventor 增田健坪仓多惠子村瀬琢
Owner TDK CORPARATION