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US4917736A
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Method of transforming a passive ferromagnetic material into a permanent magnet
Assignee: United States Department of the Army
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Filing: 1989-03-20
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Granted: 1990-04-17
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Expires: 2009-03-20
Abstract
Abstract A passive ferromagnetic material is transformed into a permanent magnet with more than double the existing energy product or "strength" by encasing a bar of the passive ferromagnetic material in an annular shell of superconductive material at a temperature above the transition temperature of the superconductive material, placing the encased ferromagnetic material into an axial magnetic field providing sufficient oersteds to magnetize the passive ferromagnetic material thereby enclosing a large amount of flux in the superconducting shell, lowering the temperature to below the transition temperature of the superconductive material whereupon all of the enclosed flux is permanently trapped, and removing the axial magnetic field.
Inventors
- 👤 Herbert A. Leupold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:15
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/012; C; C21; C21D; C21D1/00; C21D1/04; H01F41/00; H01F41/02; H01F41/0253; H01F41/0273; Y; Y10; Y10S; Y10S505/00; Y10S505/70; Y10S505/725; Y10S505/727
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
113 words
Method of transforming a passive ferromagnetic material into a permanent magnet with more than double the existing energy product or, said method including the steps of: (A) encasing a bar of the passive ferromagnetic material in an annular shell of superconductive material at a temperature above the transition temperature of the superconductive material, (B) placing the encased ferromagnetic material into an axial magnetic field providing sufficient oersteds to magnetize the passive ferromagnetic material, thereby enclosing a large amount of flux in the superconducting shell, (C) lowering the temperature to below the transition temperature of the superconductive material whereupon all of the enclosed flux is permanently trapped, and (D) removing the axial magnetic field.
Claim 2
Dependent Claim
113 words
Method of transforming a passive ferromagnetic material into a permanent magnet with more than double the existing energy product or, said method including the steps of: (A) encasing a bar of the passive ferromagnetic material in an annular shell of superconductive material at a temperature above the transition temperature of the superconductive material, (B) placing the encased ferromagnetic material into an axial magnetic field providing sufficient oersteds to magnetize the passive ferromagnetic material, thereby enclosing a large amount of flux in the superconducting shell, (C) lowering the temperature to below the transition temperature of the superconductive material whereupon all of the enclosed flux is permanently trapped, and (D) removing the axial magnetic field.
Claim 3
Dependent Claim
48 words
Method according to claim 1 wherein the passive ferromagnetic material is selected from the group consisting of iron, nickel-iron alloys containing from 40 to 80% nickel and having high magnetic permeability and electrical resistivity and an alloy of 58 parts iron, 40 parts cobalt and 2 parts vanadium.
Claim 4
Dependent Claim
12 words
Method according to claim 2 wherein the passive ferromagnetic material is iron.
Claim 5
Dependent Claim
27 words
Method according to claim 2 wherein the passive ferromagnetic material is nickel-iron alloys containing from 40 to 80% nickel and having high magnetic permeability and electrical resistivity.
Claim 6
Dependent Claim
24 words
Method according to claim 2 wherein the passive ferromagnetic material is an alloy of 58 parts iron, 40 parts cobalt and 2 parts vanadium.
Claim 7
Dependent Claim
27 words
Method according to claim 3 wherein the superconductive material is CuBa 2 Y 3 O 7 and the temperature above the transition temperature is about 90° K.
Claim 8
Dependent Claim
27 words
Method according to claim 3 wherein the superconductive material is CuBa 2 Y 3 O 7 and the temperature below the transition temperature is about 70° K.
Claim 9
Dependent Claim
21 words
Method according to claim 1 wherein the axial magnetic field is less than 100 oersteds and provided by an electrical solenoid.
Claim 10
Dependent Claim
21 words
Method according to claim 1 wherein the axial magnetic field is less than 100 oersteds and provided by a permanent magnet.
Claim 11
Dependent Claim
111 words
Method of transforming an iron bar into a permanent magnet with more than double the existing energy product said method including the steps of: (A) encasing the iron bar in an annular shell of CuBa 2 Y 3 O 7 material at about 90° K., (B) placing the encased iron bar into an axial magnetic field of less than 100 oersteds provided by an electrical solenoid to magnetize the iron bar, thereby enclosing a large amount of flux in the CuBa 2 Y 3 O 7 shell, (C) lowering the temperature to about 70° K. whereupon all of the enclosed flux is permanently trapped, and (D) removing the axial magnetic field.
Claim 12
Dependent Claim
111 words
Method of transforming an iron bar into a permanent magnet with more than double the existing energy product said method including the steps of: (A) encasing the iron bar in an annular shell of CuBa 2 Y 3 O 7 material at about 90° K., (B) placing the encased iron bar into an axial magnetic field of less than 100 oersteds provided by an electrical solenoid to magnetize the iron bar, thereby enclosing a large amount of flux in the CuBa 2 Y 3 O 7 shell, (C) lowering the temperature to about 70° K. whereupon all of the enclosed flux is permanently trapped, and (D) removing the axial magnetic field.
References Cited (Backward Citations)
No citation records indexed.
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) | 1993-04-16 | 1993-10-16 | 1994-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-16 | 1997-10-16 | 1998-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-16 | 2001-10-16 | 2002-04-17 | $7700.00 | Window Closed / Lapsed |