Claims
- 1. 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).sub.max of 5.0 MGO.sub.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.
- 2. A method of producing a sintered Fe-Cr-Co type magnet as defined in claim 1 in which the powders have an activated surface.
- 3. 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.
- 4. 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.
- 5. The method as defined in claim 2, in which any of said Fe-Cr powder or Fe-Cr-Co powder has been mechanically pulverized.
- 6. 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).sub.max of 5.0 MGO.sub.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.degree. C. to 500.degree. C. at a cooling rate of 5.degree. C./min or higher.
- 7. A method of producing the sintered Fe-Cr-Co type magnet as defined in claim 6, in which the cooling rate from 800.degree. C. to 500.degree. C. is 20.degree. C./min or higher.
- 8. 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.
- 9. 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.
- 10. The method as defined in claim 6, in which any of said Fe-Cr powder or Fe-Cr-Co powder has been mechanically pulverized.
Parent Case Info
This application is a division, of application Ser. No. 297,622, filed Aug. 31, 1981, now abandoned.
US Referenced Citations (11)
Foreign Referenced Citations (5)
Number |
Date |
Country |
1594334 |
Jul 1970 |
FRX |
55-73854 |
Jun 1980 |
JPX |
55-89460 |
Jul 1980 |
JPX |
56-254 |
Jan 1981 |
JPX |
WO8100643 |
May 1981 |
WOX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
297622 |
Aug 1981 |
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