Patent US4988673A successfully refreshed from Google Patents.
US4988673A
Expired / Lapsed
US
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Method for producing silver coated superconducting ceramic powder
Assignee: United States Department of the Navy
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Filing: 1989-08-02
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Granted: 1991-01-29
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Expires: 2009-08-02
Abstract
Abstract A process for silver coating superconducting ceramic powder by (1) coating the superconducting ceramic powder particles with AgNO3; (2) melting the AgNO3 so that it wets and forms a uniform coating over the surfaces of the particles; and (3) decomposing the AgNO3 to form a thin, uniform coating of silver metal on the surfaces of the particles. The product is a loose powder of the superconducting ceramic particles which are uniformly coated with silver metal. The powder can be cold worked (e.g., swaged, forged, etc.) to form superconducting structures such as rods or wires.
Inventors
- 👤 William Ferrando
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:35
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/626; C04B35/628; C04B35/62802; C04B35/62842; C04B35/01; C04B35/45; C04B35/4504; C04B35/4508; C04B35/4512; C04B35/4521; C04B35/4525; C04B41/00; C04B41/009; C04B41/45; C04B41/4584; C04B41/50; C04B41/51; C04B41/5116; C04B41/80; C04B41/81; C04B41/85; C04B41/88; H; H10; H10N; H10N60/00; H10N60/01; H10N60/0268; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/32; C04B2235/3205; C04B2235/3208; C04B2235/3213; C04B2235/3215; C04B2235/3224; C04B2235/3225; C04B2235/3281; C04B2235/3282; Y; Y10; Y10S; Y10S505/00; Y10S505/70; Y10S505/725; Y10S505/775; Y10S505/785
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
164 words
A process for coating superconducting ceramic powders with silver metal comprising: (1) coating superconducting ceramic powder particles with AgNO 3 ; (2) heating the AgNO 3 -coated superconducting ceramic powder at a temperature above the melting point of AgNO 3 but below the decomposition temperature of AgNO 3 until the AgNO 3 melts and forms a uniform coating over the surfaces of the superconducting ceramic particles; and (3) heating the molten AgNO 3 -coated superconducting ceramic powder at a temperature from the decomposition temperature of AgNO 3 to 50° C. below the melting point of the superconducting ceramic powder until the AgNO 3 decomposes to form a thin, uniform coating of silver metal over the surfaces of the superconducting ceramic powder particles; wherein an amount of AgNO 3 is used in step (1) which will produce upon decomposition a silver metal coated superconducting ceramic powder composite comprising from about 1 to about 25 weight percent silver metal with the remainder being the superconducting ceramic.
Claim 2
Dependent Claim
164 words
A process for coating superconducting ceramic powders with silver metal comprising: (1) coating superconducting ceramic powder particles with AgNO 3 ; (2) heating the AgNO 3 -coated superconducting ceramic powder at a temperature above the melting point of AgNO 3 but below the decomposition temperature of AgNO 3 until the AgNO 3 melts and forms a uniform coating over the surfaces of the superconducting ceramic particles; and (3) heating the molten AgNO 3 -coated superconducting ceramic powder at a temperature from the decomposition temperature of AgNO 3 to 50° C. below the melting point of the superconducting ceramic powder until the AgNO 3 decomposes to form a thin, uniform coating of silver metal over the surfaces of the superconducting ceramic powder particles; wherein an amount of AgNO 3 is used in step (1) which will produce upon decomposition a silver metal coated superconducting ceramic powder composite comprising from about 1 to about 25 weight percent silver metal with the remainder being the superconducting ceramic.
Claim 3
Dependent Claim
15 words
The process of claim 1 wherein the superconducting ceramic is a yttrium based superconducting ceramic.
Claim 4
Dependent Claim
17 words
The process of claim 2 wherein the superconducting ceramic is YBa 2 Cu 3 O 7-x .
Claim 5
Dependent Claim
15 words
The process of claim 1 wherein the superconducting ceramic is a bismuth based superconducting ceramic.
Claim 6
Dependent Claim
18 words
The process of claim 4 wherein the superconducting ceramic is Bi.sub..7 Pb.sub..3 SrCaCu 1 .8 O x .
Claim 7
Dependent Claim
15 words
The process of claim 1 wherein the superconducting ceramic is a thallium based superconducting ceramic.
Claim 8
Dependent Claim
21 words
The process of claim 6 wherein the superconducting ceramic is Tl 2 Ba 2 Ca 2 Cu 3 O 7-x .
Claim 9
Dependent Claim
46 words
The process of claim 1 wherein an amount of AgNO 3 is used in step (1) which will produce upon decomposition a silver metal coated superconducting ceramic powder composite comprising from 1 to 15 weight percent of silver metal with the remainder being the superconducting ceramic.
Claim 10
Dependent Claim
42 words
The process of claim 8 wherein the amount of AgNO 3 used in step (1) produces upon decomposition a silver metal coated superconducting ceramic powder composite comprising from 10 to 15 weight percent of silver with the remainder being the superconducting ceramic.
Claim 11
Dependent Claim
51 words
The process of claim 1 wherein the molten AgNO 3 -coated superconducting ceramic powder is heated in step (3) at a temperature of from 450° C. to 550° C. until the AgNO 3 decomposes to form a thin, uniform coating of silver metal over the surfaces of the superconducting ceramic particles.
Claim 12
Dependent Claim
23 words
The process of claim 10 wherein the temperature used in step (3) is in the range of from 450° C. to 500° C.
Claim 13
Dependent Claim
48 words
The process of claim 1 wherein in step (1) the superconducting ceramic powder is thoroughly wetted with molten AgNO 3 provided that the amount of AgNO 3 used is sufficient to produce a silver metal coated superconducting ceramic powder composite containing from 10 to 25 weight percent silver.
Claim 14
Dependent Claim
62 words
The process of claim 1 wherein in step (1) the superconducting ceramic powder is wetted with a solution of the AgNO 3 dissolved in an amount of a suitable solvent just sufficient to thoroughly wet the superconducting ceramic powder and then the solvent is removed to leave small crystals of AgNO 3 deposited on the surfaces of the superconducting ceramic powder particles.
Claim 15
Dependent Claim
11 words
The process of claim 13 wherein the solvent is ethylene glycol.
Claim 16
Dependent Claim
23 words
The process of claim 13 wherein the solvent is distilled water provided that the superconducting ceramic is not a yttrium based superconducting ceramic.
References Cited (Backward Citations)
US4826808A
Cited
US4892861A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-28 | 1994-07-30 | 1995-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-28 | 1998-07-30 | 1999-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-28 | 2002-07-30 | 2003-01-29 | $7700.00 | Window Closed / Lapsed |