US4747874A
Expired / Lapsed
US
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Rare earth-iron-boron permanent magnets with enhanced coercivity
Assignee: RARE EARTH ACQUISITIONS LLC
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Filing: 1986-05-30
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Granted: 1988-05-31
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Expires: 2006-05-30
Abstract
Abstract Permanent magnets are prepared by a method comprising mixing a particulate rare earth-iron-boron alloy with particulate aluminum, aligning the magnetic domains of the mixture, compacting the aligned mixture to form a shape, and sintering the compacted shape.
Inventors
- 👤 Mohammad H. Ghandehari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:05
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; H01F1/0577; B; B22; B22F; B22F1/00; B22F1/09
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
26 words
A composition for preparing a permanent magnet comprising: (a) a particulate alloy containing at least one rare earth metal, iron, and boron; and (b) particulate aluminum.
Claim 2
Dependent Claim
26 words
A composition for preparing a permanent magnet comprising: (a) a particulate alloy containing at least one rare earth metal, iron, and boron; and (b) particulate aluminum.
Claim 3
Dependent Claim
16 words
The composition defined in claim 1, wherein the rare earth metal comprises a light rare earth.
Claim 4
Dependent Claim
13 words
The composition defined in claim 2, wherein the rare earth metal comprises neodymium.
Claim 5
Dependent Claim
25 words
The composition defined in claim 1, wherein the alloy further contains a ferromagnetic metal selected from the group consisting of cobalt, nickel, and mixtures thereof.
Claim 6
Dependent Claim
20 words
The composition defined in claim 1, further comprising: (c) at least one particulate rare earth oxide or rare earth metal.
Claim 7
Dependent Claim
16 words
The composition defined in claim 5, wherein the rare earth oxide comprises a heavy lanthanide oxide.
Claim 8
Dependent Claim
29 words
The composition defined in claim 6, wherein the heavy lanthanide oxide is selected from the group consisting of gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, and mixtures thereof.
Claim 9
Dependent Claim
25 words
The composition defined in claim 7, wherein the heavy lanthanide oxide is selected from the group consisting of terbium oxide, dysprosium oxide, and mixtures thereof.
Claim 10
Dependent Claim
27 words
The composition defined in claim 1, wherein said particulate aluminum comprises about 0.05 to about 1 percent by weight of a permanent magnet prepared from said composition.
Claim 11
Dependent Claim
27 words
The composition defined in claim 3, wherein said particulate aluminum comprises about 0.05 to about 1 percent by weight of a permanent magnet prepared from said composition.
Claim 12
Dependent Claim
27 words
The composition defined in claim 5, wherein said particulate aluminum comprises about 0.05 to about 1 percent by weight of a permanent magnet prepared from said composition.
Claim 13
Dependent Claim
27 words
The composition defined in claim 8, wherein said particulate aluminum comprises about 0.05 to about 1 percent by weight of a permanent magnet prepared from said composition.
Claim 14
Dependent Claim
14 words
The composition defined in claim 5, wherein the rare earth oxide comprises dysprosium oxide.
Claim 15
Dependent Claim
27 words
The composition defined in claim 13, wherein said particulate aluminum comprises about 0.05 to about 1 percent by weight of a permanent magnet prepared from said composition.
Claim 16
Dependent Claim
17 words
The composition defined in claim 14, wherein said rare earth metal in said particulate alloy comprises neodymium.
References Cited (Backward Citations)
EP0101552A2
Cited
EP0106948A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-31 | 1991-11-30 | 1992-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-31 | 1995-11-30 | 1996-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-31 | 1999-11-30 | 2000-05-31 | $7700.00 | Window Closed / Lapsed |