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US4866031A
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Process for making 90 K superconductors from acetate precursor solutions
Assignee: EIDP Inc
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Filing: 1987-06-09
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Granted: 1989-09-12
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Expires: 2007-06-09
Abstract
Abstract There is disclosed an improved process for preparing a superconducting composition having the formula MBa 2 Cu 3 O x wherein M is selected from the group consisting of Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu; x is from about 6.5 to about 7.0; said composition having a superconducting transition temperature of about 90 K; said process consisting essentially of preparing a precursor solution, drying the solution of obtain a solid material, and heating and cooling the solid material under specified conditions to obtain the desired product. In another embodiment, a shaped superconducting MBa 2 Cu 3 O x article is prepared by impregnating an article of cellulose material with the precursor solution, drying the impregnated article, and heating and cooling the impregnated article under prescribed conditions to obtain the desired product.
Inventors
- 👤 John D. Bolt
- 👤 Munirpallam A. Subramanian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:40
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/01; H10N60/0268; C; C01; C01G; C01G3/00; C01G3/006; C04; C04B; C04B35/00; C04B35/01; C04B35/45; C04B35/4504; C04B35/4508; C04B35/622; C04B35/626; C04B35/63; C04B35/632; C04B35/636; C04B35/6365; C01P; C01P2002/00; C01P2002/70; C01P2002/72; Y; Y10; Y10S; Y10S264/00; Y10S264/25; Y10S264/36
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
194 words
An improved process for preparing a superconducting composition having the formula MBa 2 Cu 3 O x wherein M is selected from the group consisting of Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu; x is from about 6.5 to about 7.0; said composition having a superconducting transition temperature of about 90 K.; said process consisting essentially of (a) forming in acetic acid a mixture of M(C 2 H 3 O 2 ) 3 , barium acetate and copper acetate in an atomic ratio of M:Ba:Cu of about 1:2:3; (b) heating the resulting mixture to boiling, and adding sufficient formic acid to dissolve any undissolved starting material while maintaining boiling; (c) evaporating the solvent from the resulting solution to form a solid mass; (d) heating the resulting material in an oxygen-containing atmosphere at a temperature from about 850° C. to about 925° C. for a time sufficient to form MBa 2 Cu 3 O y , where y is from about 6.0 to about 6.4; and (e) maintaining the MBa 2 Cu 3 O y in an oxygen-containing atmosphere while cooling for a time sufficient to obtained the desired product.
Claim 2
Dependent Claim
194 words
An improved process for preparing a superconducting composition having the formula MBa 2 Cu 3 O x wherein M is selected from the group consisting of Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu; x is from about 6.5 to about 7.0; said composition having a superconducting transition temperature of about 90 K.; said process consisting essentially of (a) forming in acetic acid a mixture of M(C 2 H 3 O 2 ) 3 , barium acetate and copper acetate in an atomic ratio of M:Ba:Cu of about 1:2:3; (b) heating the resulting mixture to boiling, and adding sufficient formic acid to dissolve any undissolved starting material while maintaining boiling; (c) evaporating the solvent from the resulting solution to form a solid mass; (d) heating the resulting material in an oxygen-containing atmosphere at a temperature from about 850° C. to about 925° C. for a time sufficient to form MBa 2 Cu 3 O y , where y is from about 6.0 to about 6.4; and (e) maintaining the MBa 2 Cu 3 O y in an oxygen-containing atmosphere while cooling for a time sufficient to obtained the desired product.
Claim 3
Dependent Claim
37 words
A process according to claim 1 wherein the solid mass from step (c) is heated to a temperature from about 350° C. to about 700° C. to give a precursor powder prior to heating in step (d).
Claim 4
Dependent Claim
22 words
A process according to claim 2 wherein the precursor powder is pressed into a desired shape prior to heating in step (d).
Claim 5
Dependent Claim
23 words
A process according to claim 2 wherein the solid mass is heated to a temperature from about 375° C. to about 425° C.
Claim 6
Dependent Claim
23 words
A process according to claim 3 wherein the solid mass is heated to a temperature from about 375° C. to about 425° C.
Claim 7
Dependent Claim
15 words
A process according to claim 4 wherein x is from about 6.8 to about 7.0.
Claim 8
Dependent Claim
15 words
A process according to claim 5 wherein x is from about 6.8 to about 7.0.
Claim 9
Dependent Claim
10 words
A process according to claim 6 wherein M is Y.
Claim 10
Dependent Claim
10 words
A process according to claim 7 wherein M is Y.
Claim 11
Dependent Claim
99 words
A process for preparing precursor for a superconducting oxide composition consisting essentially of (a) forming in acetic acid a mixture of M(C 2 H 3 O 2 ) 3 , barium acetate and copper acetate in an atomic ratio of M:Ba:Cu of about 1:2:3, wherein M is selected from the group consisting of Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu; (b) heating the resulting mixture to boiling, and adding sufficient formic acid to dissolve any undissolved starting material while maintaining boiling; (c) evaporating the solvent from the resulting solution to form a solid mass.
Claim 12
Dependent Claim
99 words
A process for preparing precursor for a superconducting oxide composition consisting essentially of (a) forming in acetic acid a mixture of M(C 2 H 3 O 2 ) 3 , barium acetate and copper acetate in an atomic ratio of M:Ba:Cu of about 1:2:3, wherein M is selected from the group consisting of Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu; (b) heating the resulting mixture to boiling, and adding sufficient formic acid to dissolve any undissolved starting material while maintaining boiling; (c) evaporating the solvent from the resulting solution to form a solid mass.
Claim 13
Dependent Claim
29 words
The process of claim 10 wherein the solid mass from step (c) is heated to a temperature from about 350° C. to about 700° C. to form a powder.
Claim 14
Dependent Claim
21 words
The process of claim 11 wherein the solid mass from step (c) is heated to a temperature of about 400° 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) | 1992-09-11 | 1993-03-13 | 1993-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-11 | 1997-03-13 | 1997-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-11 | 2001-03-13 | 2001-09-12 | $7700.00 | Window Closed / Lapsed |