Metal treatment – Stock – Magnetic
Patent
1997-02-07
1998-11-24
Sheehan, John
Metal treatment
Stock
Magnetic
148104, 148101, H01F 1053
Patent
active
058401334
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an improvement of a permanent magnet, especially the one based on Co-containing Fe--Mn--R, to be served for electric and electronic elements which are very important to be used in wide fields ranging from household electric appliances to peripheral and terminal equipments of large computers.
BACKGROUND OF THE INVENTION
In recent years, demands for miniaturization and high efficiency for electric and elecronic devices and instruments have grown progressively, necessitating the permanent magnets for delivering energy in such devices and instruments to reveal more higher performances.
Presently representative permanent magnets are those of magnetically anisotropic sinters based on alnico, hard ferrite and samacoba as well as Fe--B--R(Nd).
It has been approved that such recent magnets as those based on Fe--B--Nd etc. exhibit inferior temperature characteristics and are not applicable to instruments in automobile and so on.
In the market, there is a demand for a permanent magnet of low price exhibiting superior temperature characteristics and, in particular, there is wanted a permanent magnet which exhibits markedly higher magnetic characteristics, as compared with conventional magnets, and also better temperature characteristics and is applicable mainly to products with high added values, such as generator-motor and the like.
DISCLOSURE OF THE INVENTION
The present invention has been reached from a sound research based on the above-mentioned circumstances and the invention consists in a permanent magnet of a magnetically anisotropic sinter based on Fe--Mn--R, wherein R represents one or more rare earth elements, consisting, on the basis of atomic percent, of 5-35% of one or more rare earth elements R selected among Yb, Er, Tm and Lu, 1-25% of Mn and the rest of substantially of Fe, characterized in that a part of Fe is replaced by 50 atom. % or less (excluding zero %), based on the entire structure, of Co. Here, it is particularly preferable, that it consists, on the basis of atomic percent, of 10-30% of R (wherein at least 50 atom. % of R are composed of at least one of Yb and Tm), 1-20% of Mn and the rest of substantially of Fe, wherein a part of Fe is replaced by 40% or less (excluding zero %) of Co, based on the entire alloy structure.
According to the present invention, there is provided also a permanent magnet of a magnetically anisotropic sinter based on Fe--Mn--R, wherein R represents one or more rare earth elements, consisting, on the basis of atomic percent, of 4-30%, in the total, of one or more rare earth elements R selected among Yb, Er, Tm, Lu and Y and one or more elements selected among Nd, Pr, Dy, Ho, Tb, La, Ce, Pm, Sm, Eu and Gd, 1-25% of Mn and the rest of substantially of Fe, characterized in that a part of Fe is replaced by 50% or less (excluding zero %), based on the entire alloy structure, of Co. Here, it is particularly preferable, that it consists, on the basis of atomic percent, of 10-30% of R (wherein at least 50 atom. % of R are composed of at least one of Yb and Tm), 1-20% of Mn and the rest of substantially of Fe, wherein a part of Fe is replaced by 40% or less (excluding zero %), based on the entire alloy structure, of Co.
It has, in general, been recognized that there are two kinds of Co-containing Fe alloys, namely, those in which the Curie point (Tc) increases with increasing content of Co, on the one hand, and those in which the Curie point decreases with incresing content of Co, on the other hand.
In the course of progress of the replacement of Fe content of the sinter of magnetically anisotropic permanent magnet based on Fe--Mn--R according to the present invention by Co, Tc of the resulting alloy will at first increase with the increase of Co content until it reaches a maximum at about a 1/2-replacement of the Fe content, namely at around R(Fe 0.5, Co 0.5).sub.3, before it decreases thereafter. In the case of Fe.sub.2 Mn alloy, the Tc will simply increase with the progress of the replacement of Fe by Co.
As fo
REFERENCES:
patent: 4135953 (1979-01-01), Nagel et al.
patent: 4929275 (1990-05-01), Bogatin
patent: 5211770 (1993-05-01), Ishiguro et al.
Derwent Abstract of Japan 1-278703. Nov. 1989.
English Abstract of EP 323 125 Dec. 28, 1987.
English Abstract of JP 3-253001 Nov. 12, 1991.
LandOfFree
Permanent magnet does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Permanent magnet, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Permanent magnet will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1698303