Hard magnetic material

Details Hard magnetic material Hard magnetic material

1998-12-01

2001-05-22

Sheehan, John (Department: 1742)

Metal treatment

Stock

Magnetic

C148S301000, C075S242000, C075S244000, C075S246000, C075S247000

Reexamination Certificate

active

06235129

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hard magnetic material having excellent hard magnetic characteristics.
2. Description of the Related Art
Materials generally known as hard magnetic materials having performance superior to ferrite magnets and alnico magnets (Al—Ni—Co—Fe system magnets) include a Sm—Co system magnet, a Nd—Fe—B system magnet, and the like.
The Nd—Fe—B system magnet is a magnet having high coercive force (iHc), remanent magnetization, and maximum magnetic energy product ((BH)
max
), and excellent hard magnetic characteristics, but has a problem in that since its magnetic characteristics greatly vary with temperature, it cannot be used as a constituent material for a sensor or the like, which is used at high temperatures.
The Sm—Co system magnet causes less changes in magnetic characteristics with temperature, but has a problem in that since coercive force (iHc) is lower than that of the Nd—Fe—B system magnet, hard magnetic characteristics deteriorate, particularly when it is used for a small device such as a motor, an actuator, or the like.
SUMMARY OF THE INVENTION
The present invention has been achieved for solving the above problems, and it is an object of the present invention to provide a hard magnetic material having excellent hard magnetic characteristics, particularly high coercive force (iHc).
In order to achieve the above object, the present invention utilizes the following construction.
A hard magnetic material of the present invention comprises Co as a main component, at least one element Q of P, C, Si, and B, and Sm, and has an amorphous phase and a fine crystalline phase.
A hard magnetic material of the present invention comprises Co as a main component, at least one element Q of P, C, Si and B, Sm, and at least one type element of at least one element M of Nb, Zr, Ta, and Hf, at least one element R of Sc, Y, La, Ce, Pr, Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and at least one element X of Al, Ge, Ga, Cu, Ag, Pt, and Au, and has an amorphous phase and a fine crystalline phase.
The hard magnetic material of the present invention comprises a bulk formed by heating an alloy powder having the above-described composition and then solidifying the alloy.
The bulk is preferably formed by solidification utilizing a softening phsenomenon which occurs in crystallization reaction of the amorphous phase.
In the hard magnetic material of the present invention, the texture has at least 50% by volume of fine crystalline phase having an average crystal grain size of 100 nm or less.
In the hard magnetic material of the present invention, a mixed phase state containing a soft magnetic phase and a hard magnetic phase is formed in the texture.
In the hard magnetic materials of the present invention, the soft magnetic phase contains at least one of a bcc-Fe phase, a bcc-(FeCo) phase, a D
20
E
3
Q phase containing dissolved atoms and the residual amorphous phase, and the hard magnetic phase contains at least a E
2
D
17
phase containing dissolved atoms.
D is at least one element of transition metals, and is preferably either or both of Co and Fe. E is an element at least one element of Sm, Sc, Y, La, Ce, Pr, Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and Q is at least one element of P, C, Si, and B.
In the hard magnetic material of the present invention, the crystal axis of the hard magnetic phase is oriented to impart magnetic anisotropy.
In the hard magnetic material of the present invention, the ratio Ir/Is of remanent magnetization Ir to saturation magnetization Is is 0.6 or more.
The hard magnetic material of the present invention is represented by the following composition formula:
(Co
l-f
T
f
)
100-x-y-z-t
M
x
Sm
y
R
z
Q
t
wherein T is at least one element of Fe and Ni, M is at least one element of Nb, Zr, Ta, and Hf, R is at least one element of Sc, Y, La, Ce, Pr, Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu other than Sm, Q is at least one element of P, C, Si, and B, 0≦f<0.5, 0 atomic %≦x 4≦atomic %, 8 atomic %≦y≦16 atomic %, 0 atomic %≦z 5 atomic %, 0.5 atomic %≦t≦10 atomic %, and 8 atomic %≦x+y+z≦16 atomic %.
The hard magnetic material of the present invention is represented by the following composition formula:
(Co
l-f
T
f
)
100-x-y-z-t-u
M
x
Sm
y
R
z
Q
t
X
u
wherein T is at least one element of Fe and Ni, M is at least one element of Nb, Zr, Ta, and Hf, R is at least one element of Sc, Y, La, Ce, Pr, Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu other than Sm, Q is at least one element of P, C, Si, and B, X is at least one element of Al, Ge, Ga, Cu, Ag, Pt, and Au, 0≦f<0.5, 0 atomic %≦x4≦atomic %, 8 atomic %≦y≦16 atomic %, 0 atomic %≦z≦5 atomic %, 0.5 atomic %≦t≦10 atomic %, 0 atomic %≦u≦5 atomic %, and 8 atomic %≦x+y+z≦16 atomic %.
In the hard magnetic material of the present invention, the composition ratio f is in the range of 0.2≦f<0.5.
The hard magnetic material of the present invention preferably necessarily contains Nb.
The composition ratio x is preferably in the range of 1 atomic %≦x≦3 atomic %.
The composition ratio y preferably is in the range of 10 atomic %≦y≦13 atomic %.
The composition ratio z is preferably in the range of 2 atomic %≦z≦5 atomic %.
The composition ratio t is preferably in the range of 3 atomic %≦t≦8 atomic %.
The composition ratio u is preferably in the range of 1 atomic %≦u≦3 atomic %.
The composition ratio (x+y+z) is preferably in the range of 10 atomic %≦x+y+z≦13 atomic %.


REFERENCES:
patent: 4836868 (1989-06-01), Yajima et al.
patent: 5017247 (1991-05-01), Honkura et al.
patent: 5022939 (1991-06-01), Yajima et al.
patent: 5049208 (1991-09-01), Yajima et al.
patent: 5482573 (1996-01-01), Sakurada et al.
patent: 5976273 (1999-11-01), Takeuchi et al.
patent: 55-067110 (1980-05-01), None
patent: 3-39451 (1991-02-01), None
Manrakhan W. et al., “Melt-Spun SM (Cofecuzr) ZMX (M=B or C) Nonocomposite Magnets” IEEE Transactions On Magnetics, vol. 33, No. 5, part 02, Sep. 1997, pp. 3898-3900, XP000703251.

Affiliated with

Also associated with

Rating

Hard magnetic material does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Hard magnetic material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hard magnetic material will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2528763