Compositions – Magnetic – With wax – bitumen – resin – or gum
Patent
1994-08-17
1997-07-01
Sheehan, John
Compositions
Magnetic
With wax, bitumen, resin, or gum
75349, 148101, 148104, 148302, 420 83, 420121, H01F 1057
Patent
active
056434910
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method of fabricating a rare earth element (hereinafter, referred to as "R")--Fe--B based alloy magnetic powder excellent in magnetic anisotropy, a method of fabricating an R--Fe--B--Co based alloy magnetic powder excellent in magnetic anisotropy and temperature characteristic, and further the powders fabricated by the above methods; and particularly to a method of stably fabricating on a large scale the above magnetic powders by suppressing deviation in magnetic characteristics.
The present invention also concerns a resin bonded magnet fabricated using the above R--Fe--B--Co alloy magnetic powder by injection molding or compression molding.
BACKGROUND ART
Recently, electronic devices have been required to be miniaturized, to be enhanced in efficiency, and to be diversified; and further, when being used for automobile, they have been required to withstand harsh environments exposed at high temperatures. Along with the above demands for the electronic devices, permanent magnets have been increasingly required to possess high performances. To meet these demands, rare earth magnets have been actively developed as permanent magnets, and particularly, in recent years, R--Fe--B based alloys have been focussed as permanent magnet materials exhibiting excellent magnetic characteristics. Thus R--Fe--B based alloy magnetic powders as the sources of the above R--Fe--B based alloys have been developed.
In particular, as a method of fabricating magnetic powders excellent in magnetic properties, there has been remarked a method of fabricating R--Fe--B based alloy magnetic powders by a method wherein R--Fe--B based alloys are subjected to hydrogen absorbing treatment, followed by dehydrogenation. For example, Japanese Patent Laid-open Gazette No. HEI 1-132106 discloses an R--Fe--B based alloy magnetic powder of this type.
The above R--Fe--B based alloy magnetic powder is fabricated by holding an ingot of an R--Fe--B based alloy mainly containing a ferro-magnetic R.sub.2 Fe.sub.14 B type intermetallic compound (hereinafter, referred to as "R.sub.2 Fe.sub.14 B type phase") or a powder of the ingot in a hydrogen atmosphere heated at a high temperature for hydrogen absorption; dehydrogenating at the same high temperature; and dehydrogenating the ingot or the powder thereof in a vacuum atmosphere, to thus generate the R.sub.2 Fe.sub.14 B type phase as a ferro-magnetic phase again. The R--Fe--B based alloy magnetic powder thus obtained has an aggregate structure mainly containing an extremely fine recrystallized structure of the R.sub.2 Fe.sub.14 B type phase having an average grain size of 0.05 to 3 .mu.m, and has high magnetic properties.
However, the R--Fe--B based alloy magnetic powder thus fabricated by the above method, which has the excellent magnetic properties, has a disadvantage that the magnetic anisotropy is significantly reduced and is fluctuated depending on the alloy composition and crystal structure of the ingot and grain size, and on the slight fluctuation of the conditions of the treatments such as homogenization, hydrogen absorption and dehydrogenation. The reduction and deviation of the magnetic anisotropy are extremely inconvenient in the industrial mass-production, and in the worst case, they also make difficult the industrial fabrication.
To cope with this problem, for example, Japanese Patent Laid-open Gazettes Nos. HEI 3-146608 and 4-17604 disclose a technique of heating and hydrogenating an ingot or the like together with a heat reservoir having a heat keeping function, on the basis of a supposition that the deviation of the magnetic anisotropy is generated by the fluctuation in temperature due to the exothermic reaction of the hydrogen absorbing treatment. However, this technique has problems, as being pointed out by Japanese Patent Laid-open Gazette No. HEI 5-163510, such that all the surfaces of an ingot are difficult to be contacted with a heat reservoir; that a furnace must be enlarged to contain the heat reservoir; and that the sticking and
REFERENCES:
patent: 4981532 (1991-01-01), Takeshita et al.
patent: 5228930 (1993-07-01), Nakayama et al.
patent: 5250206 (1993-10-01), Nakayama et al.
patent: 5395462 (1995-03-01), Takeshita et al.
Japanese Laid-open Patent Application, H5-329924, filed Nov. 30, 1993 (Translation enclosed).
Japanese Laid-open patent application, H4-359767, filed Dec. 28, 1992 (Translation enclosed).
Japanese Laid-open patent application, H5-128048, filed Apr. 30, 1993 (Translation enclosed).
Amahiro Yoshikazu
Honkura Yoshinobu
Matsuoka Hiroshi
Mishima Chisato
Mitarai Hironari
Aichi Steel Works Ltd.
Sheehan John
LandOfFree
Rare earth magnetic powder, its fabrication method, and resin bo does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rare earth magnetic powder, its fabrication method, and resin bo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rare earth magnetic powder, its fabrication method, and resin bo will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-594182