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Patent US5053384A successfully refreshed from Google Patents.
US5053384A
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Method of producing superconducting fibers of bismuth strontium calcium copper oxide (Bi(2212) and Bi(2223))
Assignee: Iowa State University Research Foundation Inc
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Filing: 1990-03-12
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Granted: 1991-10-01
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Expires: 2010-03-12
Abstract
Abstract Fibers of Bi(2212) have been produce by pendant drop melt extraction. This technique involves the end of a rod of Bi(2212) melted with a hydrogen-oxygen torch, followed by lowering onto the edge of a spinning wheel. The fibers are up to 15 cm in length with the usual lateral dimensions, ranging from 20 um to 30 um. The fibers require a heat treatment to make them superconducting.
Inventors
- 👤 Louis A. Schwartzkopf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:44
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/45; C04B35/4504; C04B35/4508; C04B35/622; C04B35/62227; C04B35/62231; C04B35/62254; H; H10; H10N; H10N60/00; H10N60/01; H10N60/0268; H10N60/0801; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/93; Y10S505/00; Y10S505/70; Y10S505/704; Y10S505/725; Y10S505/733; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49014
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
125 words
A method of pendant drop melt extraction forming of superconductive fibers of Bismuth (2212) or (2223) compounds, comprising: (a) heating to a temperature above the melting point of Bi(2212) or (2223) compounds, a superconductive ceramic; (b) contacting said drops with an edge of a cool wheel rotating at a speed of from about 230 rpms to about 430 rpms, which results in formation of fibers from said liquid drops on said wheel; (c) heat treating said fibers at a temperature at from about 820° C. to about 870° C. in air from about 16 hours to about 24 hours to allow crystals of Bismuth ceramic to form within said fibers; and (d) slowly cooling said fibers in to a temperature of at least 200° C.
Claim 2
Independent Claim
125 words
A method of pendant drop melt extraction forming of superconductive fibers of Bismuth (2212) or (2223) compounds, comprising: (a) heating to a temperature above the melting point of Bi(2212) or (2223) compounds, a superconductive ceramic; (b) contacting said drops with an edge of a cool wheel rotating at a speed of from about 230 rpms to about 430 rpms, which results in formation of fibers from said liquid drops on said wheel; (c) heat treating said fibers at a temperature at from about 820° C. to about 870° C. in air from about 16 hours to about 24 hours to allow crystals of Bismuth ceramic to form within said fibers; and (d) slowly cooling said fibers in to a temperature of at least 200° C.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein the heating is above 890° C.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein the speed of revolution is from about 230 rpm to about 300 rpm.
Claim 5
Dependent Claim
28 words
The method of claim 1 wherein the heating treatment of the fibers in step (c) is at a temperature of from about 820° C. to about 850° C.
Claim 6
Dependent Claim
30 words
The method of claim 1 wherein the slow cooling is to a temperature of at least 200° C. over a time of from about 9 hours to about 16 hours.
Claim 7
Dependent Claim
21 words
The method of claim 3 wherein the temperature of the cool wheel is from about 100° C. to about 300° C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-09-30 | 1995-04-01 | 1995-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-30 | 1999-04-01 | 1999-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-30 | 2003-04-01 | 2003-10-01 | $7700.00 | Window Closed / Lapsed |