Rare earth sintered magnet, raw material alloy powder for rare earth sintered magnet, and process for producing rare earth sintered magnet

A technology of sintered magnets and manufacturing methods, applied in the direction of inductance/transformer/magnet manufacturing, magnetic materials, magnetic objects, etc., can solve the problems of reduced strength of molded bodies, difficulties in sintered bodies, etc., and achieve the effect of improved orientation

Active Publication Date: 2007-04-11
TDK CORPARATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, the strength of the molded body is reduced due to the added lubricant
It is also known that peeling and cracking occur in the molded body, and it is difficult to obtain a sintered body with the required dimensional accuracy (for example, refer to Patent Document 3).

Method used

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  • Rare earth sintered magnet, raw material alloy powder for rare earth sintered magnet, and process for producing rare earth sintered magnet
  • Rare earth sintered magnet, raw material alloy powder for rare earth sintered magnet, and process for producing rare earth sintered magnet
  • Rare earth sintered magnet, raw material alloy powder for rare earth sintered magnet, and process for producing rare earth sintered magnet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0102] The influence of the particle size of the lubricant added in the pulverization step was investigated, and the results are shown in Example 1.

[0103] According to the composition of the raw material alloy is 24.5wt% Nd-6.0wt% Pr-1.8wt% Dy-0.5wt% Co-0.2wt% Al-0.07wt% Cu-1.0wt% B-the balance Fe to match the raw material metal or alloy , by melting and casting raw alloy sheets by the strip casting method. The obtained raw material alloy sheet was subjected to hydrogen pulverization, and then mechanically coarsely pulverized by a Brownian mill to obtain a coarsely pulverized powder.

[0104] To this coarsely pulverized powder, oleamide was added as a lubricant. Then, a finely pulverized powder was obtained using a jet mill.

[0105] Lubricants added at the time of fine pulverization were prepared in several different particle diameters. As a lubricant, commercially available oleamide (manufactured by Nippon Seika Co., Ltd., NEUTRON (trade name)) was used, and the lubric...

Embodiment 2

[0126] Then, the particle diameters of the raw material alloy (coarsely pulverized powder) and the lubricant used for fine pulverization were investigated, and the results are shown in Example 2.

[0127] The composition of the raw material alloy is 24.5wt%Pr-6.0wt%Dy-1.8wt%Co-0.5wt%Al-0.2wt%Cu-0.07wt%B-1.0wt%Fe. The raw alloy sheet is melted and cast by the strip casting method. The obtained raw material alloy sheet was subjected to hydrogen pulverization, and then mechanically coarsely pulverized by a Brownian mill to obtain a coarsely pulverized powder. This coarsely pulverized powder is formed into a flat plate with a thickness of about 100 to 300 μm and a size (length) of about 100 to 1000 μm. This was sieved and classified into 200 μm or more and less than 500 μm, and 500 μm or more but less than 800 μm.

[0128] As a lubricant, oleamide was frozen with liquid nitrogen and pulverized with a pulverizer. The obtained lubricant (lubricant particles) was classified by sie...

Embodiment 3

[0145] R-Fe-B based sintered magnets were produced in the following manner.

[0146] The raw metal or alloy is compounded according to the composition of 24.5wt% Nd-6.0wt% Pr-1.8wt% Dy-0.5wt% Co-0.2wt% Al-0.07wt% Cu-1.0wt% B-balance Fe. The raw alloy sheet is melted and cast by the strip casting method. The obtained raw material alloy sheet was subjected to hydrogen pulverization, followed by mechanical coarse pulverization using a Brownian mill to obtain a coarse pulverization powder.

[0147] To this coarsely pulverized powder, oleamide was added as a lubricant. Then, a jet mill was used to obtain a finely pulverized powder.

[0148] Several kinds of lubricants with different particle diameters were prepared for the lubricant added at the time of fine pulverization. As a lubricant, commercially available oleamide (manufactured by Nippon Seika Co., Ltd., NEUTRON (trade name)) was used, and the lubricant was frozen with liquid nitrogen and pulverized with a pulverizer. The...

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Abstract

A rare earth sintered magnet that realizes a high remanent flux density without detriment to coercive force and mechanical strength. There is provided a rare earth sintered magnet comprised of a sintered body whose carbon content determined by mass spectrometry is in the range of 500 to 1500 ppm, and wherein the cv-value of carbon content at a rupture plane thereof is = 200. This rare earth sintered magnet can be produced through the step of performing, in a magnetic field, pressure molding of a raw material alloy powder whose carbon content determined by mass spectrometry is = 1200 ppm and wherein providing that with respect to the characteristic X-rays of carbon determined by EPMA (Electron Probe Micro Analyzer), Cmax refers to the maximum value of X-ray intensity while Cmin refers to the minimum value of X-ray intensity, the ratio of Cmax / Cmin is = 15 to thereby obtain a molding, and the step of sintering the molding.

Description

technical field [0001] The present invention relates to a rare earth sintered magnet represented by Nd-Fe-B system, in particular to a rare earth sintered magnet with high magnetic properties and high mechanical strength. Background technique [0002] Rare earth sintered magnets represented by Nd-Fe-B anisotropic sintered magnets are widely used as high-performance magnets. In order to increase the residual magnetic flux density of the rare earth sintered magnet, it is important to improve the orientation during forming in a magnetic field. When the orientation is improved, the squareness is improved, and the magnetization rate can also be improved. Various methods of adding a lubricant to the raw material alloy powder have been proposed as methods for improving the orientation of the raw material alloy powder in a magnetic field. [0003] For example, Patent Document 1 reports that by adding a lubricant during pulverization, the dispersibility of the lubricant to the raw ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02B22F9/04
CPCB22F2009/041H01F41/0266H01F1/0577B22F2998/10C22C1/0441B22F2998/00H01F1/0536B22F3/02B22F2202/05B22F1/10B22F9/04B22F3/10
Inventor 榎户靖坂本笃司石坂力增田健伊村正明
Owner TDK CORPARATION
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