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US4051706A
Expired / Lapsed
US
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Method of making anisotropic permanent magnets of mn-al-c alloys
Assignee: Panasonic Holdings Corp
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Filing: 1975-07-01
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Granted: 1977-10-04
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Expires: 1995-07-01
Abstract
Abstract Anisotropic permanent magnets of Mn-Al-C polycrystalline alloy are produced by warm extrusion at a temperature of 530° to 830° C utilizing converging or tapered dies with lubricant interposed between the polycrystalline body and the converging die. With dies of rather small semiangles, alloys with improved magnetic properties with regard to (BH)max, and especially Br are obtained.
Inventors
- 👤 Yoichi Sakamoto
- 👤 Nobuyuki Kato
- 👤 Tadao Ohtani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:47
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; C; C22; C22C; C22C28/00; C22F; C22F1/00; C22F1/16; Y; Y10; Y10S; Y10S72/00; Y10S72/70; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49075; Y10T29/49076
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
81 words
A method of making anisotropic permanent magnet which comprises the steps of (1) preparing a polycrystalline body of an alloy comprises of the Mn-Al-C system by melting and casting (2) subjecting said alloy to heat treatment, and (3) warm extruding at a temperature of 530° to 830° C in order to make said alloy anisotropic, said warm extruding step being performed by pushing said polycrystalline body through a converging die with lubricant interposed between said polycrystalline body and said converging die.
Claim 2
Independent Claim
81 words
A method of making anisotropic permanent magnet which comprises the steps of (1) preparing a polycrystalline body of an alloy comprises of the Mn-Al-C system by melting and casting (2) subjecting said alloy to heat treatment, and (3) warm extruding at a temperature of 530° to 830° C in order to make said alloy anisotropic, said warm extruding step being performed by pushing said polycrystalline body through a converging die with lubricant interposed between said polycrystalline body and said converging die.
Claim 3
Dependent Claim
24 words
A method of making a permanent magnet according to claim 1, wherein the semiangle α of the converging die is in the range 2.5°≦α≦30°.
Claim 4
Dependent Claim
24 words
A method of making a permanent magnet according to claim 1, wherein the semiangle α of the converging die is in the range 5°≦α≦20°.
Claim 5
Dependent Claim
32 words
A method of making a permanent magnet according to claim 1, wherein the converging die comprises a axi-symmetric internal die surface which bounds said polycrystalline body in order to deform the same.
Claim 6
Dependent Claim
36 words
A method of making a permanent magnet according to claim 1, wherein the converging die comprises a pair of inclined internal die surfaces which is plane-symmetric about the meridian plane including the axis of the die.
Claim 7
Dependent Claim
21 words
A method of making a permanent magnet according to claim 1, wherein the converging die comprises a curved internal die profile.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-03 | 1981-04-04 | 1981-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-03 | 1985-04-04 | 1985-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-03 | 1989-04-04 | 1989-10-04 | $7700.00 | Window Closed / Lapsed |