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Method for producing raw material powder for rare earth sintered magnet, method for producing rare earth sintered magnet, granule and sintered article

一种烧结磁体、制造方法的技术，应用在电感/变压器/磁铁制造、磁性材料、磁性物体等方向，能够解决不能获得成形体尺寸精度、颗粒产额降低、耗费时间等问题

Active Publication Date: 2007-03-28
TDK CORPARATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the filling property of the powder in the mold is poor, the powder cannot be sufficiently filled into the mold, so there is a problem that the dimensional accuracy of the molded body cannot be obtained, or filling the mold itself takes time and impairs production efficiency
Under the effect of these collisions, the ensuing problem is particle destruction, that is, the yield of particles is reduced.

Method used

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  • Method for producing raw material powder for rare earth sintered magnet, method for producing rare earth sintered magnet, granule and sintered article
  • Method for producing raw material powder for rare earth sintered magnet, method for producing rare earth sintered magnet, granule and sintered article
  • Method for producing raw material powder for rare earth sintered magnet, method for producing rare earth sintered magnet, granule and sintered article

Examples

Experimental program
Comparison scheme
Effect test

no. 1 Embodiment

[0147] The raw material alloy is produced by the strip continuous casting method, and its composition is: 26.5wt% Nd-5.9wt% Dy-0.25wt% Al-0.5wt% Co-0.07wt% Cu-1.0wt% B-balance Fe .

[0148] Next, a hydrogen pulverization treatment is performed, that is, the raw material alloy is allowed to absorb hydrogen at room temperature, and then dehydrogenated in an Ar atmosphere at 600° C. for 1 hour.

[0149] The alloy subjected to the hydrogen pulverization treatment is mixed with 0.05 to 0.1% of a lubricant that contributes to improvement of pulverization and orientation during molding. The mixing of the lubricant may be performed for about 5 to 30 minutes using, for example, a Nauta mixer. Then, a finely pulverized powder having an average particle diameter of 5.0 μm was obtained using a jet mill.

[0150]To the above finely pulverized powder, various organic liquids shown in FIG. 4 were added in the amounts shown in FIG. 4, and then sufficiently kneaded with a mortar. Pellets we...

Embodiment 7

[0153] SEM photographs of the molded articles of Example 7 and Comparative Example 1 are shown in FIG. 6 . 6( a ) is an SEM photograph of the molded body of Example 7, and FIG. 6( b ) is a SEM photograph of the molded body of Comparative Example 1. FIG. As shown in Figure 6(a), the molded body formed by granulating particles using an organic liquid has voids compared to the molded body formed by not granulating finely pulverized powder (see Figure 6(b)). Fewer, denser shaped bodies.

[0154] The obtained molded body was heated up to 1080° C. in vacuum or in an Ar atmosphere, and held for 4 hours to perform sintering. Next, the obtained sintered body was subjected to two-stage aging treatment at 800° C.×1 hour and 560° C.×1 hour (both in an Ar atmosphere).

[0155] The measurement results of the magnetic properties of the obtained sintered body are shown in FIG. 4 . In addition, Fig. 4 also shows the magnetic properties of the sintered magnet of Comparative Example 1 and the...

no. 2 Embodiment

[0160] To the finely pulverized powder produced in the same manner as in the first example, 6 wt% of various organic liquids shown in FIG. 9 were added, and then granules were produced in the same manner as in the first example. For the obtained pellets, the angle of repose was measured in the same manner as in the first example. The results are shown together in FIG. 9 . In addition, FIG. 9 also shows the angle of repose of the finely pulverized powder before granulation. The particles obtained above were exposed for 20 to 300 minutes in a reduced-pressure atmosphere (room temperature) having a vacuum degree shown in FIG. 9 .

[0161] The obtained pellets were molded in a magnetic field in the same manner as in the first example to obtain a molded body.

[0162] The obtained compact was subjected to sintering and two-stage aging treatment under the same conditions as in the first example.

[0163] The measurement results of the magnetic properties of the obtained sintered ...

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Abstract

A method for producing a raw material powder for a rare earth sintered magnet, characterized in that it has a step of adding an organic liquid to primary alloy particles having a prescribed composition, to prepare a mixture, and a step of preparing, by the use of the mixture, granules formed by attaching primary alloy particles to one another via the organic liquid. In the method, it is preferred that the organic liquid is added in an amount of 1.5 to 15.0 wt % to the primary alloy particles. When the amount is less than 1.5 wt %, it may be difficult to prepare granules with good efficiency, and when the amount is more than 15.0 wt %, an organic moisture may present in an excess amount and it may be required to remove an unnecessary moisture for carrying out compacting in an appropriate magnetic field. The above method allows the improvement of the dimensional accuracy of the resultant compact for a rare earth sintered magnet and the improvement of productivity with no greatly adverse effect on characteristics of the magnet, due to the above granules exhibiting excellent fluidity.

Description

technical field [0001] The present invention relates to raw material powders used in the manufacture of rare earth sintered magnets represented by Nd-Fe-B series, and particularly relates to a method of improving the resistance to magnetic field during forming by granulating the raw material powders. The filling property of the mold can achieve higher production efficiency, and at the same time, it is easy to adapt to the miniaturization of rare earth sintered magnets. Background technique [0002] When producing rare earth sintered magnets, magnetic properties such as saturation magnetic flux density and coercive force are ensured by making finer raw material powders to be sintered. However, the miniaturization of the raw material powder is a factor that impairs the dimensional accuracy and production efficiency of the compact. [0003] The raw material powder is formed into a compact by press molding in a magnetic field. Forming in a magnetic field is to apply a static m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F1/00C22C33/02H01F1/053H01F1/08H01F41/02C22C19/07C22C38/00B22F1/10B22F1/103B22F1/148
CPCC22C1/0441B22F3/087B22F5/003B22F9/04B01J2/28B01J2/10B22F1/0059H01F41/0266B22F2998/00B22F1/0096H01F41/0273C22C38/005C22C19/07B22F2009/042B22F2009/041B22F2998/10B22F3/093B22F2001/0066H01F1/08C22C33/02H01F1/0577B22F1/103B22F1/148B22F1/10B22F3/02B22F2202/05B22F2202/01B22F2201/20B22F1/107B22F3/10
Inventor 榎户靖马场文崇石坂力增田健
Owner TDK CORPARATION
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