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Patent US4913745A successfully refreshed from Google Patents.
US4913745A
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Method for producing a rare earth metal-iron-boron anisotropic bonded magnet from rapidly-quenched rare earth metal-iron-boron alloy ribbon-like flakes
Assignee: Tokin Corp
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Filing: 1988-03-22
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Granted: 1990-04-03
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Expires: 2008-03-22
Abstract
Abstract A method is disclosed for producing a rare earth metal-transition metal-boron (R-T-B) bonded magnet with a magnetic anisotropy. R-T-B alloy ribbons and/or ribbon-like flakes containing R 2 T 14 B fine crystals are prepared with a thickness of 20-1,000 μm by rapidly-quenching method. The ribbons and/or flakes are crushed and ground into a magnetic powder of particle sizes smaller than the value of the ribbon thickness. The magnetic powder is mixed with binder agent and formed into desired bulk-shape body in an aligning magnetic field to produce the bonded magnet with the magnetic anisotropy. In order to improve the magnetic properties, the ribbons and/or flakes can be heat-treated at a temperature of 650°-950° C. The magnetic powder can also be teat-treated at a temperature of 500°-700° C.
Inventors
- 👤 Tadakuni Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:22
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; B; B22; B22D; B22D11/00; B22D11/06; B22D11/0611; B22D11/0622; B22F; B22F9/00; B22F9/002; B22F9/008; B22F9/02; B22F9/06; B22F9/08; B22F9/10; H01F1/0575; H01F1/0577; H01F1/0578
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
173 words
A method for producing a rare earth metal-transition metal-boron (R-T-B) anisotropic bonded magnet wherein a magnetic powder of R-T-B alloy substantially consisting of R 2 T 14 B is dispersed in and bonded by binder agent, the method comprising steps of: preparing said R-T-B alloy in a molten state; rapidly quenching said molten alloy to form an R-T-B alloy ribbon and/or ribbonlike flakes, each having a thickness of 20-1,000 μm and having R 2 T 14 B crystal grains; the crystal grains having an average particle size less than the thickness of said ribbon and/or flakes and varying in orientation in the direction of said thickness; crushing and grinding said ribbon and/or flakes into a magnetic powder having an average particle size which is less than the thickness of said ribbon and/or flakes before grinding; mixing said magnetic powder with a binder agent to form a mixture; and then forming said mixture into a desired bulk-shape body while disposed within an aligning magnetic flux to produce a bonded magnet characterized by magnetic anisotropy.
Claim 2
Independent Claim
173 words
A method for producing a rare earth metal-transition metal-boron (R-T-B) anisotropic bonded magnet wherein a magnetic powder of R-T-B alloy substantially consisting of R 2 T 14 B is dispersed in and bonded by binder agent, the method comprising steps of: preparing said R-T-B alloy in a molten state; rapidly quenching said molten alloy to form an R-T-B alloy ribbon and/or ribbonlike flakes, each having a thickness of 20-1,000 μm and having R 2 T 14 B crystal grains; the crystal grains having an average particle size less than the thickness of said ribbon and/or flakes and varying in orientation in the direction of said thickness; crushing and grinding said ribbon and/or flakes into a magnetic powder having an average particle size which is less than the thickness of said ribbon and/or flakes before grinding; mixing said magnetic powder with a binder agent to form a mixture; and then forming said mixture into a desired bulk-shape body while disposed within an aligning magnetic flux to produce a bonded magnet characterized by magnetic anisotropy.
Claim 3
Dependent Claim
30 words
A method as claimed in claim 1, wherein said R 2 T 14 B crystal grains of said alloy ribbon and/or flakes have an average grain size of 0.01-20 μm.
Claim 4
Dependent Claim
14 words
A method as claimed in claim 1, wherein said transition metal T is Fe.
Claim 5
Dependent Claim
28 words
A method as claimed in claim 1, wherein said transition metal T consists by, atomic ratio, of Co 45 at % or less and the balance of Fe.
Claim 6
Dependent Claim
15 words
A method as claimed in claim 1, wherein said rare earth metal R is Nd.
Claim 7
Dependent Claim
19 words
A method as claimed in claim 1, wherein said rare earth metal R consists of cerium didymium and Dy.
Claim 8
Dependent Claim
27 words
A method as claimed in claim 6, wherein said cerium didymium consisting of Ce 5 wt %, Pr 15 wt %, and the substantially balance of Nd.
Claim 9
Dependent Claim
16 words
A method as claimed in claim 6, wherein the amount of Dy is 5 at %.
Claim 10
Dependent Claim
27 words
A method as claimed in claim 1, further comprising a step of heat-treating said magnetic powder at a temperature of 500°-700° C. prior to said mixing step.
Claim 11
Dependent Claim
31 words
A method as claimed in claim 1, further comprising a step of heat-treating said alloy ribbon and/or flakes at a temperature of 650°-950° C. prior to said crushing and grinding step.
Claim 12
Dependent Claim
26 words
A method as claimed in claim 10, further comprising step of heat-treating said magnetic powder at a temperature of 500°-700° C. prior to said mixing step.
Claim 13
Dependent Claim
32 words
A method as claimed in claim 1, wherein said forming step comprises a process for pressing said mixture into said desired bulk-shape body in said aligning magnetic field by a pressing force.
Claim 14
Dependent Claim
33 words
A method as claimed in claim 12, wherein said binder agent is a thermosetting resin having a curing temperature, said bulk-shape body being heated at said curing temperature to produce said bonded magnet.
Claim 15
Dependent Claim
14 words
A method as claimed in claim 13, wherein said binder agent is epoxy resin.
Claim 16
Dependent Claim
20 words
A method as claimed in claim 1, wherein said binder agent is a thermoplastic resin having a resin melting temperature.
Claim 17
Dependent Claim
13 words
A method as claimed in claim 15, wherein said binder agent is polyethylene.
Claim 18
Dependent Claim
38 words
A method as claimed in claim 15, wherein said forming step comprises a process for heating and injecting said mixture into a mould at said resin melting temperature in said aligning magnetic field to produce said bonded magnet.
Claim 19
Dependent Claim
44 words
A method as claimed in claim 1, wherein said molten alloy is rapidly quenched by ejecting it through a small orifice onto an outer peripheral chill surface of a rotating quenching disk, said ejected molten alloy thereby forming a rapidly-quenched ribbon and/or ribbon-like flakes.
Claim 20
Dependent Claim
33 words
A method as claimed in claim 18 wherein a magnetic field is applied in a radial direction of said quenching disk so that said ejected molten alloy is cooled in said magnetic field.
Claim 21
Dependent Claim
52 words
A method as claimed in claim 18, wherein said quenching disk is provided with a plurality of projections formed in said chilling surface and a cooling plate is disposed adjacent said quenching disk, said molten alloy ejected onto the chilling surface is sprayed onto said cooling plate to form flat ribbon-like flakes.
Claim 22
Dependent Claim
20 words
A method as claimed in claim 20, wherein each of said flat ribbon-like flakes has a thickness of 7-500 μm.
Claim 23
Dependent Claim
46 words
A method as claimed in claim 18, wherein after said molten alloy is deposited onto said chilling surface and is rapidly quenched to form a ribbon, an outer surface of said ribbon is rapidly quenched by engagement with another quenching disk to obtain a rapidly-quenched ribbon.
Claim 24
Dependent Claim
35 words
A method as claimed in claim 1, wherein said molten alloy is sprayed and atomized through a spray nozzle onto a cooling plate and rapidly cooled on said cooling plate to form flat ribbon-like flakes.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-04-02 | 1993-10-02 | 1994-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-02 | 1997-10-02 | 1998-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-02 | 2001-10-02 | 2002-04-03 | $7700.00 | Window Closed / Lapsed |