US4975416A
Expired / Lapsed
US
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Method of producing superconducting ceramic wire
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1989-11-13
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Granted: 1990-12-04
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Expires: 2009-11-13
Abstract
Abstract A superconducting ceramic wire is prepared from a superconducting ceramic-forming oxide composition by melting, the composition and quenching the melt to form a dense glass, which is soften and wire-drawn in a furnace. The resulting wire is heat-treated to form crystals and made into a superconducting ceramic wire. The wire has a flexibility and remarkable superconductivity which can further be improved by applying pressure to be made more dense and repeating the heat-treatment.
Inventors
- 👤 Masashi Onishi
- 👤 Takashi Kohgo
- 👤 Tetsuya Ohsugi
- 👤 Gotaro Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:05
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/01; H10N60/0268; H10N60/0801; Y; Y10; Y10S; Y10S505/00; Y10S505/725; Y10S505/733; Y10S505/739; Y10S505/74; Y10S505/742
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
81 words
A method of producing a superconducting ceramic wire of a Bi-Sr-Ca-Cu-O system which comprises the steps: (a) homogeneously melting a mixture consisting essentially of oxygen-bearing Bi, Sr, Ca and Cu compounds capable of being converted into a superconducting ceramic and silver in an amount sufficient for accelerating the formation of superconductive crystal nuclei of said system and quenching the melt to form a glass, (b) wire-drawing the glass, and (c) conducting a heat-treatment of the drawn glass to effect recrystallization thereof.
Claim 2
Independent Claim
81 words
A method of producing a superconducting ceramic wire of a Bi-Sr-Ca-Cu-O system which comprises the steps: (a) homogeneously melting a mixture consisting essentially of oxygen-bearing Bi, Sr, Ca and Cu compounds capable of being converted into a superconducting ceramic and silver in an amount sufficient for accelerating the formation of superconductive crystal nuclei of said system and quenching the melt to form a glass, (b) wire-drawing the glass, and (c) conducting a heat-treatment of the drawn glass to effect recrystallization thereof.
Claim 3
Dependent Claim
70 words
A method of producing a superconducting ceramic wire according to claim 1, wherein said method further comprises the steps: (d) applying pressure to the recrystallized drawn glass in step (c) with or without a metal cover to cause crystal cleavage, and (e) conducting further heat-treatment of the crystal-cleaved drawn glass to further recrystallize it, the further heat-treatment being conducted before, during or after the application of pressure in step (d).
Claim 4
Dependent Claim
21 words
A method of producing a superconducting ceramic wire according to claim 2, wherein steps (d) and (e) are repeated several times.
Claim 5
Dependent Claim
25 words
A method of producing a superconducting ceramic wire according to claim 1, wherein the system contains the metals in an atomic weight ratio of Bi:Sr:Ca:Cu=2:2:2:3.
Claim 6
Dependent Claim
21 words
A method of producing a superconducting ceramic wire according to claim 1, wherein said melting is carried out at 1150°±100° C.
Claim 7
Dependent Claim
25 words
A method of producing a superconducting ceramic wire according to claim 1, wherein the quenching is conducted by pouring the glass onto a metal plate.
Claim 8
Dependent Claim
34 words
A method of producing a superconducting ceramic wire according to claim 1, wherein said wire-drawing is effected at a temperature corresponding to a viscosity of 10 6 -10 4 poises of the drawn glass.
Claim 9
Dependent Claim
18 words
A method of producing a superconducting ceramic wire according to claim 7, wherein said temperature is 450°±50° C.
Claim 10
Dependent Claim
39 words
A method of producing a superconducting ceramic wire according to claim 1, wherein said heat-treatment is conducted at a temperature of 420°to 430 ° C. to form crystal nuclei and then at 800°to 870° C. to effect recrystallization growth.
Claim 11
Dependent Claim
25 words
A method of producing a superconducting ceramic wire according to claim 1, wherein said heat-treatment is conducted at a temperature of 800° to 870° C.
Claim 12
Dependent Claim
34 words
A method of producing a superconducting ceramic wire according to claim 1, wherein the mixture, contains a metal carbonate, and is calcined at about 800° C. so as to remove the resulting carbon therefrom.
Claim 13
Independent Claim
101 words
A method of producing a superconducting ceramic wire of a (Bi plus Pb)-Sr-Ca-Cu-O system in which Pb is present in an atomic weight of up to 35% of (Bi plus Pb); which comprises the steps: (a) homogeneously melting a mixture consisting essentially of oxygen-bearing Bi, Sr, Ca, Cu and Pb compounds capable of being converted into a superconducting ceramic and silver in an amount sufficient for accelerating the formation of superconductive crystal nuclei of said system and quenching the melt to form a glass, (b) wire-drawing the glass, and (c) conducting a heat-treatment of the drawn glass to effect recrystallization thereof.
Claim 14
Independent Claim
101 words
A method of producing a superconducting ceramic wire of a (Bi plus Pb)-Sr-Ca-Cu-O system in which Pb is present in an atomic weight of up to 35% of (Bi plus Pb); which comprises the steps: (a) homogeneously melting a mixture consisting essentially of oxygen-bearing Bi, Sr, Ca, Cu and Pb compounds capable of being converted into a superconducting ceramic and silver in an amount sufficient for accelerating the formation of superconductive crystal nuclei of said system and quenching the melt to form a glass, (b) wire-drawing the glass, and (c) conducting a heat-treatment of the drawn glass to effect recrystallization thereof.
Claim 15
Dependent Claim
70 words
A method of producing a superconducting ceramic wire according to claim 12, wherein said method further comprises the steps: (d) applying pressure to the recrystallized drawn glass in step (c) with or without a metal cover to cause crystal cleavage, and (e) conducting further heat-treatment of the crystal-cleaved drawn glass to further recrystallize it, the further heat-treatment being conducted before, during or after the application of pressure in step (d).
Claim 16
Dependent Claim
21 words
A method of producing a superconducting ceramic wire according to claim 12, wherein steps (d) and (e) are repeated several times.
Claim 17
Dependent Claim
27 words
A method of producing a superconducting ceramic wire according to claim 12, wherein the system contains the metals in an atomic weight ratio of (Bi plus Pb):Sr:Ca:Cu=2:2:2:3.
Claim 18
Dependent Claim
21 words
A method of producing a superconducting ceramic wire according to claim 12, wherein said melting is carried out at 1150°±100° C.
Claim 19
Dependent Claim
25 words
A method of producing a superconducting ceramic wire according to claim 12, wherein the quenching is conducted by pouring the glass onto a metal plate.
Claim 20
Dependent Claim
34 words
A method of producing a superconducting ceramic wire according to claim 12, wherein said wire-drawing is effected at a temperature corresponding to a viscosity of 10 6 -10 4 poises of the drawn glass.
Claim 21
Dependent Claim
18 words
A method of producing a superconducting ceramic wire according to claim 18, wherein said temperature is 450°±50° C.
Claim 22
Dependent Claim
40 words
A method of producing a superconducting ceramic wire according to claim 12, wherein said heat-treatment is conducted at a temperature of 420° to 430° C. to form crystal nuclei and then at 800° to 870° C. to effect recrystallization growth.
Claim 23
Dependent Claim
25 words
A method of producing a superconducting ceramic wire according to claim 12, wherein said heat-treatment is conducted at a temperature of 800° to 870° C.
Claim 24
Dependent Claim
34 words
A method of producing a superconducting ceramic wire according to claim 12, wherein the mixture, contains a metal carbonate, and is calcined at about 800° C. so as to remove the resulting carbon therefrom.
Claim 25
Dependent Claim
30 words
A method of producing a superconducting ceramic wire according to claim 12, wherein Pb is present in said system in an amount from 10 to 35% of (Bi plus Pb).
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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) | 1993-12-03 | 1994-06-04 | 1994-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-03 | 1998-06-04 | 1998-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-03 | 2002-06-04 | 2002-12-04 | $7700.00 | Window Closed / Lapsed |