JPS61125114A - Manufacture of rare earth magnet - Google Patents

Abstract

PURPOSE:To obtain a sintered thin rare earth magnet material which has few sintering defects such as a camber or deformation by sintering the thin pressed form or rare earth magnet material powder between the same quality and the same shape thicker pressed powder compact in the manufacturing process of a rare earth magnet. CONSTITUTION:A thin ring shape pressed powder compact 2 is sintered between thick ring shape pressed powder compacts 4 and 4 in place of holding plates and powder 5 which has difficulty in reacting with the pressed powder compact is filled between these compacts and between a base plate 3 and the form. This method can expect the same effect when a thick ring shape pressed powder compact 6 which is difficult in deformation is sintered. A normal material such as samarium series may be used for rare earth magnet material powder. Samarium oxide (Sm2O3), etc. are used for powder which has difficulty in reacting with the pressed powder compact or the base plate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for sintering a green compact of rare earth magnet material powder without causing sintering defects in a rare earth magnet manufacturing process.

[Background technology]

For example, thin flat rare earth magnets are often used in rotors for small motors that require dimensional accuracy.

Generally, in order to obtain such thin-walled flat magnets, a thick-walled powder compact is sintered and aged, and then cut into thin-walled flat plate shapes. This results in material loss.

One possible method to reduce material loss is to perform powder compaction into a thin flat plate from the beginning, then sinter and age it. However, the thinner the compact is compared to the size of the compact, the more uneven the density may be during powder filling or after pressure forming using a press, resulting in warpage during sintering. Deformation becomes more noticeable.

[Purpose of the invention]

In view of the above circumstances, an object of the present invention is to obtain a thin sintered body of rare earth magnetic material with few sintering defects.

[Disclosure of the invention]

In order to achieve the above object, the present invention provides a method for obtaining a thin compacted compact of rare earth magnet material powder by sintering in the manufacturing process of a rare earth magnet. The gist of this paper is a method for producing rare earth magnets, which is characterized by sintering them between the two.

That is, in the sintering process of a rare earth magnet material compact, the present invention sandwiches a thin compact compact between thicker compacts of the same material and shape, and further presses the compact as necessary. Thin-walled rare earth materials with fewer sintering defects are produced by interposing (sprinkling) powder that does not easily react with the powder compact and the compact, or between the powder compact and the substrate. Makes it possible to obtain magnets. As described above, the method of the present invention is capable of obtaining a thin rare earth magnet material sintered body with few sintering defects such as warping and deformation, and at the same time obtaining a thick rare earth magnet material sintered body. This makes it possible. Incidentally, if a method of interposing a powder that does not easily react with the compacted compact or the substrate is also used, adhesion of the sintered bodies or the sintered body and the substrate can be prevented.

For example, when sintering a thin ring-shaped powder compact, as shown in FIG.
If the presser plate 1 is placed on top of the presser plate 1 and sintered, if the thickness of the powder compact is extremely thin compared to the size of the compact, ring-back powder compaction will occur. The body 2 is often deformed into an elliptical shape, as shown in FIG.

On the other hand, in the method of the present invention, as shown in FIG. Powder 5, which does not easily react with the powder compact, is interposed between the two and between it and the substrate 3 for sintering. By doing so, the same effect as shown in FIG. 4 can be expected when sintering a thick ring-shaped powder compact 6 that is difficult to warp or deform.

Since the method of the present invention is as described above, the labor of cutting such as when obtaining a thin-walled compacted sintered body from a thick-walled compacted compacted sintered body can be saved, and no material loss occurs. Furthermore, magnets for different purposes, such as thin-walled and thick-walled magnets, can be manufactured at the same time.

As the rare earth magnet material powder, a common samarium thread ring may be used. Samarium oxide (3m203) or the like is used as a powder that does not easily react with the powder compact or the substrate. The molding and sintering conditions may be the same as usual.

The present invention will be described in detail below.

(Example 1) Material powder composition S m (Coo, q3Cuo, o6 F eo, 2Z
r,,o3),,7 Average grain size approx. 4μ Dimensions of compacted product Thin wall...outer diameter φ35, inner diameter φ221m, thickness 1.3
mm thick wall...outer diameter φ35mm, inner diameter φ22, thickness 3
Dragon molding conditions 20KOe magnetic field, press pressure 1.5 ton/c
Powder substrate SUS 304 with mold release agent Sm2O3 The above was installed as shown in Fig. 3 and sintered in an argon atmosphere at 1200°C for 1 hour.
As shown in FIG.
A holding plate ring (outer diameter φ36 fl, inner diameter φ18 mm, thickness 1 fl) 1 was placed and sintered. As comparative example 2, the fifth
As shown in the figure, three thin-wall compacted bodies 2 were stacked on a substrate 3 and sintered. In both cases, sintering was performed under the same conditions as in Example 1.

When the roundness of the thin-walled molded body after sintering is expressed as follows, the results are as shown in Table 1. However, the number of measurements for each was 6, and the roundness was expressed as an average value.

Table 1 [Example 2] In Example 1, the installation method was changed to 2(I) as shown in Figure 6.
When sintering was performed by sandwiching the thin-walled compacted compact 2 of J between three thick-walled compacted compacts 4, the roundness of the thin-walled compact was 99% or more, and Example 1 The results were similar.

〔Effect of the invention〕

As described above, in this invention, a thin-walled powder compact is sandwiched between thick-walled powder compacts and sintered, so that a thin-walled, sintered compact with less warpage and deformation can be obtained. can.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a comparative method, FIG. 2 is a plan view of a thin-walled sintered body obtained by the method, FIG. FIG. 5 is a cross-sectional view showing a method for obtaining a sintered meat body, FIG. 5 is a cross-sectional view showing another comparative method, and FIG. 6 is a cross-sectional view showing another embodiment of the method of the present invention. 2.4.6...Powder compact 3...Substrate 5...
Powder agent that is difficult to react Patent attorney Takehiko Matsumoto Fig. 1 Fig. 2 Fig. 3 Fig. 4 and Fig. 5 Relationship with the Sunset Incident Patent Applicant Address: 1048 Kadoma, Kadoma City, Osaka Name (583) Matsushita Electric Works Co., Ltd. Representative: Sadao Fujii 4, Agent 6, Specification subject to amendment 7゜Amendment Contents + 1) The second line from the bottom of No. 6 of the specification “6 items,
"In addition, in Comparative Example 2, only the middle thin-walled powder compact 2 of the three sheets is measured" is inserted between "" and "flat".

Claims (3)

[Claims] (1) In the manufacturing process of rare earth magnets, when sintering a thin powder compact of rare earth magnet material powder, it is sandwiched between thicker compacts of the same material and shape and sintered. A manufacturing method for rare earth magnets. (2) A method for producing a rare earth magnet according to claim 1, wherein a powder that does not easily react with the compact is interposed between the compact and the compact. (3) A method for producing a rare earth magnet according to claim 1 or 2, in which a powder that does not easily react with the compact is interposed between the compact and the substrate receiving the compact.