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R-t-b sintered magnet

A R-T-B, sintered magnet technology, applied in the direction of magnetic objects, magnetic materials, inorganic material magnetism, etc., can solve the problems of low thermal stability, reduced coercive force, temperature rise, etc.

Active Publication Date: 2014-06-25
TDK CORPARATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

One is that due to the low thermal stability, the coercive force decreases significantly as the temperature rises.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0058] Raw material alloys having compositions A and D in Table 1 were produced by strip continuous casting.

[0059] The prepared raw material alloy A and raw material alloy D were mixed at a mixing ratio of 0.95 / 0.05, and hydrogen storage was performed at room temperature for 90 minutes, followed by dehydrogenation treatment at 650° C. for 60 minutes in an argon atmosphere and coarse pulverization.

[0060] 0.10% by mass of oleic acid amide was added as a grinding aid to the coarsely ground powder of the raw material alloy. Thereafter, it was finely pulverized by a jet mill using high-pressure nitrogen to obtain a finely pulverized powder with an average particle diameter of 4.0 μm.

[0061] [Table 1]

[0062]

[0063] An ingot corresponding to the composition of G was high-frequency melted, and the molten metal was rapidly cooled by a roll to form a thin strip of a Dy alloy compound including the composition of G in Table 1. The produced ribbon is pulverized by a dry m...

Embodiment 2

[0070] The raw material alloy with the composition of A and D in Table 1 was finely pulverized in the same manner as in Example 1, and the compound of the alloy containing Dy in the composition of G in Table 1 was prepared in the same manner as in Example 1, with a concentration of 0.80% by mass. It was added to the finely pulverized powder of the raw material alloy, and an evaluation sample was produced in the same manner as in Example 1.

Embodiment 3

[0072] Evaluation samples were prepared in the same manner as in Example 1 except that the raw material alloys having the compositions B and D in Table 1 were used.

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Abstract

An R-T-B based sintered magnet maintains high magnetic properties and decreases usage of heavy rare earth elements. The magnet includes main phase grains and grain boundary phases, the main phase grain containing a core portion and a shell portion. X in the main phase LR(2-x)HRxT14B of the core portion ranges from 0.00 to 0.07; x in the main phase LR(2-x)HRxT14B of the shell portion ranges from 0.02 to 0.40; and the maximum thickness of the shell portion ranges from 7 nm to 100 nm. LR contains Nd and one or more light rare earth elements consisting of Y, La, Ce, Pr and Sm; HR contains Dy or / and Tb and one or more heavy rare earth elements consisting of Gd, Ho, Er, Tm, Yb and Lu; T contains Fe or / and Co and one or two kinds of Mn and Ni; and B represents boron partly replaced by C (carbon).

Description

technical field [0001] The present invention relates to R-T-B (R is one or more than two kinds of Y (yttrium) and rare earth elements, T is one or two or more transition metal elements that make Fe necessary or make Fe and Co necessary, and B is boron And part of the boron is replaced by C (carbon)) based sintered magnet. Background technique [0002] Among rare-earth permanent magnets, especially R-T-B sintered magnets are used in various electrical equipment due to their excellent magnetic properties. However, there are also several technical problems to be solved in the R-T-B system sintered magnet having excellent magnetic properties. One is that the coercive force decreases remarkably as the temperature rises due to low thermal stability. Therefore, by adding heavy rare earth elements represented by Dy, Tb, and Ho to increase the coercive force at room temperature, even if the coercive force decreases due to temperature rise, it can be maintained to the extent that th...

Claims

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Application Information

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IPC IPC(8): H01F1/057C22C19/07C22C38/00H01F1/08B22F3/00C22C33/02
CPCC22C38/005C22C19/07C22C38/00H01F1/0577C22C38/06H01F1/0536C22C38/001C22C2202/02C22C33/02C22C38/10C22C38/16
Inventor 国枝良太早川拓马千叶哲也西川健一藤川佳则
Owner TDK CORPARATION
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