R-t-b rare earth sintered magnet

A R-T-B, sintered magnet technology, applied in the direction of permanent magnets, magnetic materials, magnetic objects, etc., can solve the problems of reduced residual magnetic flux density of permanent magnets, increased cost, expensive heavy rare earth elements, etc.

Active Publication Date: 2012-09-26
TDK CORPARATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the saturation magnetization becomes smaller, and as a result, the residual magnetic flux density, which is an index of the magnetic strength of the permanent magnet, decreases.
In addition, since heavy rare earth elements such as Dy and Tb are very expensive, using them in large quantities will lead to an increase in cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0058] (Example 1) Two types of alloys A and B having predetermined compositions were prepared by strip casting. In addition, both alloys A and B contain 0.2% by mass of Al (aluminum). Proportion and mix alloy A and alloy B according to the mass ratio of 9:1, and carry out coarse pulverization. Specifically, after allowing the mixed alloy to absorb hydrogen gas at room temperature, it was heated at 650° C. for 1 hour in an inert gas atmosphere to perform a dehydrogenation treatment to obtain a pulverized product. Thereafter, the obtained pulverized product was cooled to room temperature in an inert gas atmosphere.

[0059]10% by mass of lauric acid amide powder was added to the obtained pulverized product as a pulverization aid, and it was mixed for 30 minutes under an inert atmosphere using a Nauta mixer. Thereafter, it was pulverized with a high-pressure nitrogen jet mill to obtain a raw material fine powder having an average particle size (corresponding to a volume-based ...

Embodiment 2

[0062] (Example 2, Comparative Examples 1-3)

[0063] R-T-B based rare earth sintered magnets were produced in the same manner as in Example 1, except that the conditions of the aging treatment were as shown in Table 1.

[0064] [Table 1]

[0065]

[0066] [Evaluation of Magnetic Properties]

[0067] Use a BH tracer (BH tracer) to measure the magnetic properties of the R-T-B series rare earth sintered magnets of each of the examples and comparative examples produced, and obtain Br (remanent magnetic flux density), HcJ (coercive force) and Hk / HcJ (squareness ratio). The obtained results are summarized in Table 2. The squareness ratio is obtained by the following formula (1) using HcJ and Hk. The squareness ratio is an index of magnet performance, and indicates the degree to which a hysteresis loop measured using a B-H recorder has an angle in the second quadrant. Hk in the formula (1) is the external magnetic field strength when the ratio of the magnetization to the re...

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PUM

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Abstract

The invention provides an R-T-B rare earth sintered magnet 100 including R 2 T 14 B-containing crystal grains as the main phase 10, and having an R L -T-M 1 based compound 12 at the grain boundary triple points, wherein R represents a rare earth element, T represents at least one element selected from among Fe, Co and Cu, B represents boron, R L represents a light rare earth element, and M 1 represents at least one element selected from among Al, Zn and Ga.

Description

technical field [0001] The invention relates to an R-T-B series rare earth sintered magnet. Background technique [0002] R-T-B rare earth sintered magnets are used in various motors such as voice coil motors for HDDs (hard disk drives), generators, and the like because they have high magnetic properties. In recent years, the demand for hybrid vehicles and wind power generation has rapidly expanded in response to increased interest in environmental issues. Accompanied by such a trend, there is a desire to increase the performance of motors and generators, and the development of R-T-B rare earth sintered magnets having better magnetic properties than conventional ones is required. [0003] R-T-B rare earth sintered magnets used in hybrid vehicles and wind power generation are used in environments with large temperature changes. In order not to lose magnetic properties even if it is used for a long time in such an environment, countermeasures against irreversible thermal dem...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F7/02H01F1/057H01F1/08
CPCC22C38/06C22C38/005C22C38/10C22C28/00C22C38/16H01F1/0577B22F2201/20C22C33/0278
Inventor 国枝良太千叶哲也早川拓马藤原笃
Owner TDK CORPARATION
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