Permanent magnet, and motor and power generator using the same
In one embodiment, a permanent magnet includes a composition expressed by R p Fe q M r Cu s Co 100-p-q-r-s (R is a rare-earth element, M is at least one element selected from Zr, Ti, and Hf, 10≤p≤13.5 at %, 28≤q≤40 at %, 0.88≤r≤7.2 at %, and 3.5≤s≤13.5 at %), and a metallic structure including a cell phase having a Th 2 Zn 17 crystal phase, and a cell wall phase. A Fe concentration (C1) in the cell phase is in a range from 28 at % to 45 at %, and a difference (C1−C2) between the Fe concentration (C1) in the cell phase and a Fe concentration (C2) in the cell wall phase is larger than 10 at %.
1. A permanent magnet comprising a sintered compact, the sintered compact comprising:
a composition expressed by the following composition formula:
R p Fe q M r Cu s Co 100-p-q-r-s
wherein, R is at least one element selected from the group consisting of rare-earth elements, and 50 at % or more of the element R is Sm,
M is at least one element selected from the group consisting of Zr, Ti, and Hf,
p is a number satisfying 10<p<13.5 at %,
q is a number satisfying 30<q<40 at %,
r is a number satisfying 1.78<r<7.2 at %, and
s is a number satisfying 3.5<s<13.5 at %; and
a metallic structure including a cell phase having a Th 2 Zn 17 crystal phase, and a cell wall phase surrounding the cell phase,
wherein a Fe concentration (C1) in the cell phase is in a range from 30.1 at % to 32.3 at %, and a difference (C1−C2) between the Fe concentration (C1) in the cell phase and a Fe concentration (C2) in the cell wall phase is in a range from 12.2 at % to 23.0 at %,
wherein the sintered compact has a density of 8.22×10 3 kg/m 3 or more and 8.31×10 3 kg/m 3 or less, and
wherein a coercive force of the permanent magnet is 870 kA/m or more.
2. The permanent magnet of claim 1 , wherein 50 at % or more of the element M is Zr.
3. The permanent magnet of claim 1 , wherein r is a number satisfying 1.95≤r≤7.2 at %.
4. A motor comprising the permanent magnet of claim 1 .
5. A power generator comprising the permanent magnet of claim 1 .
6. The motor of claim 4 , further comprising:
a stator; and
a rotor, arranged in the stator, comprising the permanent magnet.
7. The power generator of claim 5 , further comprising:
a stator comprising the permanent magnet; and
a rotor arranged in the stator.
8. A vehicle comprising the motor of claim 4 .
9. A vehicle comprising the power generator of claim 5 .
10. A permanent magnet comprising a sintered compact, the sintered compact comprising:
a composition expressed by the following composition formula:
R p Fe q M r Cu s (Co 100-a A a ) 100-p-q-r-s
wherein, R is at least one element selected from the group consisting of rare-earth elements, and 50 at % or more of the element R is Sm,
M is at least one element selected from the group consisting of Zr, Ti, and Hf,
A is at least one element selected from the group consisting of Ni, V, Cr, Mn, Al, Ga, Nb, Ta, and W,
p is a number satisfying 10≤p≤13.5 at %,
q is a number satisfying 30≤q≤40 at %,
r is a number satisfying 1.78≤r≤7.2 at %,
s is a number satisfying 3.5≤s≤13.5 at %, and
a is a number satisfying a ≤20 at %; and
a metallic structure including a cell phase having a Th 2 Zn 17 crystal phase, and a cell wall phase surrounding the cell phase,
wherein a Fe concentration (C1) in the cell phase is in a range from 30.1 at % to 32.3 at %, and a difference (C1−C2) between the Fe concentration (C1) in the cell phase and a Fe concentration (C2) in the cell wall phase is in a range from 12.2 at % to 23.0 at %,
wherein the sintered compact has a density of 8.22×10 3 kg/m 3 or more and 8.31×10 3 kg/m 3 or less, and
wherein a coercive force of the permanent magnet is 870 kA/m or more.