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US4601876A
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Sintered Fe-Cr-Co type magnetic alloy and method for producing article made thereof
Assignee: Proterial Ltd
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Filing: 1984-08-13
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Granted: 1986-07-22
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Expires: 2004-08-13
Abstract
Abstract A sintered Fe-Cr-Co type magnetic alloy consisting essentially of 20-35% Cr, 3-15% Co and the balance substantially of Fe and a method of producing an article made of the alloy are disclosed. The method comprises the steps of blending at least one of an Fe-Cr powder and Fe-Cr-Co powder with a carbonyl Fe-powder and a Co-powder, if necessary to make up to said alloy composition, to provide a powder blend, the average particle size of said Fe-Cr powder and Fe-Cr-Co powder being 200 mesh or smaller in size, and the surface of these powders having been activated; compacting the resulting powder blend to provide a compact; sintering the resulting compact in an atmosphere in which the total amount of oxygen and nitrogen has been restricted to not more than 3 ppm; and effecting the heat treatment and magnetization of the resulting sintered alloy.
Inventors
- 👤 Michio Yamashita
- 👤 Setsuo Fujimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:52
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/06; H01F1/08; H01F1/086; B; B22; B22F; B22F1/00; B22F1/09; C; C22; C22C; C22C33/00; C22C33/02; C22C33/0257; C22C33/0278; C22C33/0285
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
104 words
A method of producing a sintered Fe-Cr-Co type magnet consisting essentially of 20-35% Cr, 3-15% Co and the balance substantially of Fe, which has a maximum energy product (BH) max of 5.0 MGO e or more comprising: blending at least one of an Fe-Cr powder and Fe-Cr-Co powder with a carbonyl Fe-powder and, if necessary, a Co-powder to provide a powder blend, the average particle size of said Fe-Cr powder, Fe-Cr-Co powder and the carbonyl Fe-powder being 200 mesh or smaller in size; compacting the resulting powder blend to provide a compact; and sintering the resulting compact in a vacuum or a non-oxidizing atmosphere.
Claim 2
Independent Claim
104 words
A method of producing a sintered Fe-Cr-Co type magnet consisting essentially of 20-35% Cr, 3-15% Co and the balance substantially of Fe, which has a maximum energy product (BH) max of 5.0 MGO e or more comprising: blending at least one of an Fe-Cr powder and Fe-Cr-Co powder with a carbonyl Fe-powder and, if necessary, a Co-powder to provide a powder blend, the average particle size of said Fe-Cr powder, Fe-Cr-Co powder and the carbonyl Fe-powder being 200 mesh or smaller in size; compacting the resulting powder blend to provide a compact; and sintering the resulting compact in a vacuum or a non-oxidizing atmosphere.
Claim 3
Dependent Claim
22 words
A method of producing a sintered Fe-Cr-Co type magnet as defined in claim 1 in which the powders have an activated surface.
Claim 4
Dependent Claim
28 words
A method of producing the sintered Fe-Cr-Co type magnet as defined in claim 2, in which a sigma-powder and a carbonyl Fe-powder are used as a starting powder.
Claim 5
Dependent Claim
30 words
The method as defined in claim 2, in which said carbonyl Fe-powder is partly replaced with Fe-powder having a particle size of 200 mesh or less and an activated surface.
Claim 6
Dependent Claim
21 words
The method as defined in claim 2, in which any of said Fe-Cr powder or Fe-Cr-Co powder has been mechanically pulverized.
Claim 7
Independent Claim
133 words
A method of producing the sintered Fe-Cr-Co type magnet consisting essentially of 20-35% Cr, 3-15% Co and the balance substantially of Fe, which has a maximum energy product (BH) max of 5.0 MGO e or more comprising: blending at least one of an Fe-Cr powder and Fe-Cr-Co powder with a carbonyl Fe-powder and, if necessary, a Co-powder to provide a powder blend, the average particle size of said Fe-Cr powder, Fe-Cr-Co powder and the carbonyl Fe-powder being 200 mesh or smaller in size, the surface of these powders having been activated; compacting the resulting powder blend to provide a compact; sintering the resulting compact in the vacuum or a non-oxidizing atmosphere; and cooling the sintered body after sintering from 800° C. to 500° C. at a cooling rate of 5° C./min or higher.
Claim 8
Independent Claim
133 words
A method of producing the sintered Fe-Cr-Co type magnet consisting essentially of 20-35% Cr, 3-15% Co and the balance substantially of Fe, which has a maximum energy product (BH) max of 5.0 MGO e or more comprising: blending at least one of an Fe-Cr powder and Fe-Cr-Co powder with a carbonyl Fe-powder and, if necessary, a Co-powder to provide a powder blend, the average particle size of said Fe-Cr powder, Fe-Cr-Co powder and the carbonyl Fe-powder being 200 mesh or smaller in size, the surface of these powders having been activated; compacting the resulting powder blend to provide a compact; sintering the resulting compact in the vacuum or a non-oxidizing atmosphere; and cooling the sintered body after sintering from 800° C. to 500° C. at a cooling rate of 5° C./min or higher.
Claim 9
Dependent Claim
30 words
A method of producing the sintered Fe-Cr-Co type magnet as defined in claim 6, in which the cooling rate from 800° C. to 500° C. is 20° C./min or higher.
Claim 10
Dependent Claim
28 words
A method of producing the sintered Fe-Cr-Co type magnet as defined in claim 6, in which a sigma-powder and a carbonyl Fe-powder are used as a starting powder.
Claim 11
Dependent Claim
30 words
The method as defined in claim 6, in which said carbonyl Fe-powder is partly replaced with Fe-powder having a particle size of 200 mesh or less and an activated surface.
Claim 12
Dependent Claim
21 words
The method as defined in claim 6, in which any of said Fe-Cr powder or Fe-Cr-Co powder has been mechanically pulverized.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1989-07-21 | 1990-01-20 | 1990-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-21 | 1994-01-20 | 1994-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-21 | 1998-01-20 | 1998-07-22 | $7700.00 | Window Closed / Lapsed |