US4076561A
Expired / Lapsed
US
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Method of making a laminated rare earth metal-cobalt permanent magnet body
Assignee: Motors Liquidation Co
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Filing: 1976-10-15
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Granted: 1978-02-28
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Expires: 1996-10-15
Abstract
Abstract In a preferred embodiment thin layers of rare earth metal-cobalt powder comprising an outer layer of RCo 5 and a discrete transitional layer of R 2 Co 17 are compressed against an adjacent thicker layer of iron powder to form a laminated green compact, with the rare earth-cobalt powdered material being magnetically aligned. The green laminate body is then sintered to densify the rare earth-cobalt material layer to a body wherein the pores are substantially noninterconnecting. The laminate structure is then magnetized. By this method a strong rare earth-cobalt (RCo 5 ) permanent magnet body is produced in which the rare earth-cobalt layer may be very thin (of the order of 1 to 2 millimeters) but of relatively large surface area and supported by a strong iron layer so as to be durable in handling, manufacturing and use. It is possible to press an RCo 5 layer directly onto a powdered iron layer when the oxygen content of the iron is suitably low. The method will also produce an R 2 Co 17 -iron composite.
Inventors
- 👤 Robert W. Lee
- 👤 John J. Croat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:45
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/0555; H01F1/0557; H02; H02K; H02K1/00; H02K1/06; H02K1/12; H02K1/17; H02K23/00; H02K23/02; H02K23/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
152 words
A method of making a laminate permanent magnet body having a rare earth metal-cobalt permanent magnet layer supported on a base layer, said method comprising forming in a die a first powder layer containing an RCo 5 composition where R denotes a rare earth metal, a second powder layer containing an R 2 Co 17 composition, and a third powder layer of a composition selected from the group consisting of iron and iron-based ferromagnetic alloys, subjecting the layers to a magnetic field to magnetically orient the rare earth metal-cobalt composition powder, compressing the distinct layers to form a self-sustaining laminated green compact, and sintering the compact at a temperature in the range of about 950° to 1200° C. to densify the compact, the thickness of the R 2 Co 17 layer in said compact being at least sufficient to form a continuous layer between the RCo 5 layer and the iron-containing layer.
Claim 2
Independent Claim
152 words
A method of making a laminate permanent magnet body having a rare earth metal-cobalt permanent magnet layer supported on a base layer, said method comprising forming in a die a first powder layer containing an RCo 5 composition where R denotes a rare earth metal, a second powder layer containing an R 2 Co 17 composition, and a third powder layer of a composition selected from the group consisting of iron and iron-based ferromagnetic alloys, subjecting the layers to a magnetic field to magnetically orient the rare earth metal-cobalt composition powder, compressing the distinct layers to form a self-sustaining laminated green compact, and sintering the compact at a temperature in the range of about 950° to 1200° C. to densify the compact, the thickness of the R 2 Co 17 layer in said compact being at least sufficient to form a continuous layer between the RCo 5 layer and the iron-containing layer.
Claim 3
Independent Claim
136 words
A method of making a laminate permanent magnet body having a rare earth metal-cobalt permanent magnet layer supported on a base layer, said method comprising forming in a die a first powder layer consisting essentially of an SmCo 5 composition, a second powder layer consisting essentially of Sm 2 Co 17 , and a third powder layer consisting essentially of iron, subjecting the layers to a magnetic field to magnetically orient the samarium-cobalt composition powder, compressing the distinct layers to form a self-sustaining laminated green compact, and sintering the compact at a temperature in the range of about 950° to 1200° C. to densify the compact, the thickness of the R 2 Co 17 layer in said compact being at least sufficient to form a continuous layer between the RCo 5 layer and the iron-containing layer.
Claim 4
Independent Claim
136 words
A method of making a laminate permanent magnet body having a rare earth metal-cobalt permanent magnet layer supported on a base layer, said method comprising forming in a die a first powder layer consisting essentially of an SmCo 5 composition, a second powder layer consisting essentially of Sm 2 Co 17 , and a third powder layer consisting essentially of iron, subjecting the layers to a magnetic field to magnetically orient the samarium-cobalt composition powder, compressing the distinct layers to form a self-sustaining laminated green compact, and sintering the compact at a temperature in the range of about 950° to 1200° C. to densify the compact, the thickness of the R 2 Co 17 layer in said compact being at least sufficient to form a continuous layer between the RCo 5 layer and the iron-containing layer.
Claim 5
Independent Claim
115 words
A method of making a laminate permanent magnet body having a rare earth metal-cobalt permanent magnet layer supported on a base layer, said method comprising forming in a die a first powder layer consisting essentially of an R 2 Co 17 composition where R denotes a rare earth metal, and a second powder layer of a composition selected from the group consisting of iron and iron-based ferromagnetic alloys, subjecting the layers to a magnetic field to magnetically orient the rare earth metal-cobalt composition powder, compressing the distinct layers to form a self-sustaining laminated green compact, and sintering the compact at a temperature in the range of about 950° to 1200° C. to densify the compact.
Claim 6
Independent Claim
115 words
A method of making a laminate permanent magnet body having a rare earth metal-cobalt permanent magnet layer supported on a base layer, said method comprising forming in a die a first powder layer consisting essentially of an R 2 Co 17 composition where R denotes a rare earth metal, and a second powder layer of a composition selected from the group consisting of iron and iron-based ferromagnetic alloys, subjecting the layers to a magnetic field to magnetically orient the rare earth metal-cobalt composition powder, compressing the distinct layers to form a self-sustaining laminated green compact, and sintering the compact at a temperature in the range of about 950° to 1200° C. to densify the compact.
Claim 7
Independent Claim
103 words
A method of making a laminate permanent magnet body having a rare earth metal-cobalt permanent magnet layer supported on a base layer, said method comprising forming in a die a first powder layer consisting essentially of an RCo 5 composition, and a second powder layer of iron containing no more than one atomic percent of oxygen, subjecting the layers to a magnetic field to magnetically orient the rare earth metal-cobalt composition powder, compressing the distinct layers to form a self-sustaining laminated green compact, and sintering the compact at a temperature in the range of about 950° to 1200° C. to densify the compact.
Claim 8
Independent Claim
103 words
A method of making a laminate permanent magnet body having a rare earth metal-cobalt permanent magnet layer supported on a base layer, said method comprising forming in a die a first powder layer consisting essentially of an RCo 5 composition, and a second powder layer of iron containing no more than one atomic percent of oxygen, subjecting the layers to a magnetic field to magnetically orient the rare earth metal-cobalt composition powder, compressing the distinct layers to form a self-sustaining laminated green compact, and sintering the compact at a temperature in the range of about 950° to 1200° C. to densify the compact.
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) | 1981-02-27 | 1981-08-29 | 1982-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-27 | 1985-08-29 | 1986-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-27 | 1989-08-29 | 1990-02-28 | $7700.00 | Window Closed / Lapsed |