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US 2026/0290663 A1Published application
Sintered r-t-b based magnet
AssigneeProterial, Ltd.
InventorFutoshi KUNIYOSHI
Life of this patent
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Abstract
A sintered R-T-B based magnet containing: R: 26.5 mass % or more and 31.5 mass % or less (R is a rare earth element and contains at least one or two selected from the group consisting of Nd and Pr); M: 0.40 mass % or more and 1.50 mass % or less (M is at least one selected from the group consisting of Ga, Cu, Zn, Al, and Si, and necessarily contains Cu); B: 0.85 mass % or more and 0.94 mass % or less; T: 61.5 mass % or more (T is Fe and Co, and 90% or more of T is Fe in mass ratio); O: 0.05 mass % or more and 0.30 mass % or less; Tb: 0.20 mass % or less; and Dy: 0.30 mass % or less, the sintered R-T-B based magnet satisfying the formula: 26.0 mass %≤([Nd]+[Pr]+[Ce]+[La]+[Dy]+[Tb])−12([O]+[C])≤27.7 mass %.
Claims6
1:
- A sintered R-T-B based magnet comprising:
- R:
- 26.5 mass % or more and 31.5 mass % or less (R is a rare earth element and contains one or two selected from the group consisting of Nd and Pr);
- M:
- 0.40 mass % or more and 1.50 mass % or less (M is at least one selected from the group consisting of Ga, Cu, Zn, Al, and Si, and necessarily contains Cu);
- B:
- 0.85 mass % or more and 0.94 mass % or less;
- T:
- 61.5 mass % or more (T is Fe and Co, and 90% or more of T is Fe in mass ratio);
- O:
- 0.05 mass % or more and 0.30 mass % or less;
- Tb:
- 0.20 mass % or less;
- and
- Dy:
- 0.30 mass % or less,
- the sintered R-T-B based magnet satisfying the following Formula (1),
- wherein in a range from a surface to a depth of 200 μm, a concentration of one or two selected from the group consisting of Nd and Pr and a concentration of Cu gradually decrease in a depth direction from the surface,
- the sintered R-T-B based magnet necessarily comprises Ga as M, and
- a content of Ga is 0.3 mass % or more, and in a range from the surface to a depth of 200 μm, a concentration of Ga does not gradually decrease:
- 26.
- mass
-
- %
- ≤
- (
- [
- Nd
- ]
- +
- [
- Pr
- ]
- +
- [
- Ce
- ]
- +
- [
- La
- ]
- +
- [
- Dy
- ]
- +
- [
- Tb
- ]
- )
- -
- 12
-
- (
- [
- O
- ]
- +
- [
- C
- ]
- )
- ≤
- 27.7
- mass
-
- %
- (
- 1
- )
- where, [Nd], [Pr], [Ce], [La], [Dy], [Tb], [O], and [C] are contents of Nd, Pr, Ce, La, Dy, Tb, O, and C expressed in mass %, respectively.
68 more elements
2:
- The sintered R-T-B based magnet according to claim 1, wherein B:
- 0.85 mass % or more and 0.88 mass % or less.
3:
- A method for producing the sintered R-T-B based magnet according to claim 1, the method comprising:
- preparing a sintered R-T-B based body;
- preparing an R1-M alloy;
- and
- diffusing the R1-M alloy into the sintered R-T-B based body,
- wherein the sintered R-T-B based body contains 0.3 mass % or more of Ga, and
- the R1-M alloy comprises:
- 65 mass % or more and 95 mass % or less of R1, wherein R1 is one or two selected from the group consisting of Nd and Pr;
- and
- 5 mass % or more and 35 mass % or less of M, wherein M is at least one selected from the group consisting of Cu, Zn, and Si, and necessarily contains Cu.
7 more elements
4:
- The method for producing the sintered R-T-B based magnet according to claim 3, wherein the sintered R-T-B based body further comprises 0.85 mass % or more and 0.88 mass % or less of B.
5:
- The method for producing the sintered R-T-B based magnet according to claim 3, wherein the sintered R-T-B based body further comprises:
- R:
- 26.3 mass % or more and 31.3 mass % or less (R is a rare earth element and contains one or two selected from the group consisting of Nd and Pr);
- B:
- 0.85 mass % or more and 0.88 mass % or less;
- T:
- 61.5 mass % or more (T is Fe and Co, and 90% or more of T is Fe in mass ratio);
- M:
- 0.40 mass % or more and 1.50 mass % or less (M is at least one selected from the group consisting of Ga, Cu, Zn, Al, and Si, and necessarily contains Cu);
- Tb:
- 0.20 mass % or less;
- and
- Dy:
- 0.30 mass % or less,
- and satisfies the following Formula (2):
- 25.8
- mass
-
- %
- ≤
- (
- [
- Nd
- ]
- +
- [
- Pr
- ]
- +
- [
- Ce
- ]
- +
- [
- La
- ]
- +
- [
- Dy
- ]
- +
- [
- Tb
- ]
- )
- -
- 12
-
- (
- [
- O
- ]
- +
- [
- C
- ]
- )
- ≤
- 27.5
- mass
-
- %
- (
- 2
- )
- where [Nd], [Pr], [Ce], [La], [Dy], [Tb], [O], and [C] are contents of Nd, Pr, Ce, La, Dy, Tb, O, and C expressed in mass %, respectively.
63 more elements
6:
- The method for producing the sintered R-T-B based magnet according to claim 3, wherein a Ga content in the sintered R-T-B based body is equal to or greater than a Ga content in the sintered R-T-B based magnet.