EP0306928A2
Expired / Lapsed
EP
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Magnet for motor and method of manufacturing same
Assignee: Proterial Ltd
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Filing: 1988-09-07
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Granted: —
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Expires: 2008-09-07
Abstract
Abstract In a magnetically anisotropic magnet for use in a motor, comprising at least one rare earth element (R), Fe and boron (B), and having fine crystal grains, Ga is added so that the magnet has a surface magnification of not less than 6, a residual magnetic flux density in the direction of easy magnetization of not less than 11 kG and a coercive force of not less than 12 kOe. The invention also provides a method of producing such a magnetically anisotropic magnet for use in a motor, comprising the steps of: forming flakes by rapid quenching a molten alloy consisting of at least one rare earth element (R), Fe, boron (B) and an optional metal element (M); compacting the flakes to provide a green compact; and warm plastic working the green compact at a temperature between 600°C and 800°C at a strain rate of 0.0001 to 0.1 per second with a plastic working ratio (ho/h) of not less than 2.
Inventors
- 👤 Yasuto Nozawa
- 👤 Shigeho Tanigawa
- 👤 Katsunori Iwasaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 14:55
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/057; H01F1/0571; H01F1/0575; H01F1/0576; B; B22; B22F; B22F3/00; B22F3/12; B22F3/14; H02; H02K; H02K1/00; H02K1/02; H02K15/00; H02K15/02; H02K15/03
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
74 words
A magnetically anisotropic magnet for use in a motor, comprising at least one rare earth element (R), Fe and boron (B), said magnet having fine crystal grains, characterized by Ga added in the magnet so that the magnet has a surface magnification of not less than 6, a residual magnetic flux density in the direction of easy magnetization of not less than 11 kG and a coercive force of not less than 12 kOe.
Claim 2
Dependent Claim
74 words
A magnetically anisotropic magnet for use in a motor, comprising at least one rare earth element (R), Fe and boron (B), said magnet having fine crystal grains, characterized by Ga added in the magnet so that the magnet has a surface magnification of not less than 6, a residual magnetic flux density in the direction of easy magnetization of not less than 11 kG and a coercive force of not less than 12 kOe.
Claim 3
Dependent Claim
148 words
A magnet for use in a motor according to Claim 1 having a residual magnetic flux density in the direction of easy magnetization of not less than 11 kG and a coercive force of not less than 12 kOe, wherein the composition of said magnet is RaFe bal Co b B c Ga d M e in terms of atomic percent in which composition R is at least one element selected from a group consisting of Nd, Pr, Dy, Tb and Ce which R satisfies (Nd + Pr)/R ≧ 0.7, M is at least one element selected from a group consisting of Zn, Al, Si, Nb, Ta, Ti, Zr, Hf and W, 12≦, a ≦ 18,0 ≦ b ≦ 30, 4 ≦ c ≦ 10,0 < d ≦ 3, and 0 ≦ e ≦ 2 , and the average crystal grain size is not more than 0.5 µm.
Claim 4
Independent Claim
131 words
A method of producing a magnetically anisotropic magnet for use in a motor, comprising the steps of; forming flakes by rapid quenching a molten alloy consisting of at least one rare earth element (R), Fe, boron (B) and an optional metal element (M); compacting the flakes to provide a green compact; and warm plastic working the green compact at a temperature between 600°C and 800°C at a strain rate of 0.0001 to 0.1 per second with a plastic working ratio (ho/h) of not less than 2 so that a resultant magnet is magnetically anisotropic and has a surface magnification of not less than 6, a residual magnetic flux density in the direction of easy magnetization of not less than 11 kG, and a coercive force of not less than 12 kOe.
Claim 5
Independent Claim
131 words
A method of producing a magnetically anisotropic magnet for use in a motor, comprising the steps of; forming flakes by rapid quenching a molten alloy consisting of at least one rare earth element (R), Fe, boron (B) and an optional metal element (M); compacting the flakes to provide a green compact; and warm plastic working the green compact at a temperature between 600°C and 800°C at a strain rate of 0.0001 to 0.1 per second with a plastic working ratio (ho/h) of not less than 2 so that a resultant magnet is magnetically anisotropic and has a surface magnification of not less than 6, a residual magnetic flux density in the direction of easy magnetization of not less than 11 kG, and a coercive force of not less than 12 kOe.
Claim 6
Dependent Claim
120 words
A method of manufacturing a magnet for use in a motor according to Claim 3, wherein the alloy composition is RaFe bal Co b B c Ga d M e in terms of atomic percent in which the R is at least one element selected from a group consisting of Nd, Pr, Dy, Tb and Ce which satisfies (Nd + Pr)/R ≧ 0.7, M is at least one element selected from a group consisting of Zn, Al, Si, Nb, Ta, Ti, Zr, Hf and W, 12 ≦ a ≦ 18, 0 ≦ b ≦ 30, 4 ≦ c ≦ 10, 0 < d ≦ 3, and 0 ≦ e ≦ 2 , and said warm plastic working is warm upsetting.
References Cited (Backward Citations)
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