WO1989007161A1 - Preparation of superconducting oxides by electrochemical oxidation: anodic superconductors - Google Patents
Preparation of superconducting oxides by electrochemical oxidation: anodic superconductors Download PDFInfo
- Publication number
- WO1989007161A1 WO1989007161A1 PCT/US1989/000308 US8900308W WO8907161A1 WO 1989007161 A1 WO1989007161 A1 WO 1989007161A1 US 8900308 W US8900308 W US 8900308W WO 8907161 A1 WO8907161 A1 WO 8907161A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- anode
- superconducting oxide
- alloy
- superconducting
- oxide
- Prior art date
Links
- 238000006056 electrooxidation reaction Methods 0.000 title abstract description 5
- 239000002887 superconductor Substances 0.000 title description 3
- 238000002360 preparation method Methods 0.000 title description 2
- 238000000034 method Methods 0.000 claims abstract description 13
- 239000000956 alloy Substances 0.000 claims abstract description 12
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 12
- 239000003792 electrolyte Substances 0.000 claims abstract description 11
- 239000002243 precursor Substances 0.000 claims abstract description 10
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 4
- 238000007712 rapid solidification Methods 0.000 claims description 3
- 229910052691 Erbium Inorganic materials 0.000 claims description 2
- 229910052693 Europium Inorganic materials 0.000 claims description 2
- 229910052688 Gadolinium Inorganic materials 0.000 claims description 2
- 229910052771 Terbium Inorganic materials 0.000 claims description 2
- 229910052775 Thulium Inorganic materials 0.000 claims description 2
- 229910052769 Ytterbium Inorganic materials 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 229910052746 lanthanum Inorganic materials 0.000 claims description 2
- 230000001590 oxidative effect Effects 0.000 claims description 2
- 229910052692 Dysprosium Inorganic materials 0.000 claims 1
- 229910052689 Holmium Inorganic materials 0.000 claims 1
- 230000003647 oxidation Effects 0.000 description 9
- 238000007254 oxidation reaction Methods 0.000 description 9
- 230000015572 biosynthetic process Effects 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000011255 nonaqueous electrolyte Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 1
- -1 La2-xBaxCuO4-y Chemical class 0.000 description 1
- 239000007832 Na2SO4 Substances 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- ZOMNIUBKTOKEHS-UHFFFAOYSA-L dimercury dichloride Chemical class Cl[Hg][Hg]Cl ZOMNIUBKTOKEHS-UHFFFAOYSA-L 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000009689 gas atomisation Methods 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000012442 inert solvent Substances 0.000 description 1
- 238000002074 melt spinning Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/34—Anodisation of metals or alloys not provided for in groups C25D11/04 - C25D11/32
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N60/00—Superconducting devices
- H10N60/01—Manufacture or treatment
- H10N60/0268—Manufacture or treatment of devices comprising copper oxide
- H10N60/0296—Processes for depositing or forming copper oxide superconductor layers
Definitions
- This invention relates to superconducting materials.
- Superconductors are materials having zero resistance to the flow of electrons below a certain critical temperature, T c . It is known that certain metal oxides, e.g., La 2-x Ba x CuO 4-y , La 2-x Sr x CuO 4-y , Ba 2 YCu 2 O 9-Y , etc. exhibit superconductivity. It is desirable to provide such oxides in forms, e.g., wires or thin films, that permit practical utilization of their superconductive property.
- the invention features preparing a superconducting oxide by electrochemical oxidation.
- an electrochemical cell containing an anode made of an alloy of the metallic precursors of the superconducting oxide is provided.
- a surface of the anode is in contact with the electrolyte of the cell, and the anode is electrochemically oxidized to form the superconducting oxide.
- the metallic precursors are present in the alloy in the stoicherr.etric proportions of the metals in the oxide.
- the metallic precursors are La, M, and Cu and the superconducting oxide has the formula La 2-y M x CuO 4-y .
- M is an alkaline earth element such as Ba, Sr, or Ca.
- the metallic precursors are rare earth elements (N), Ba, and Cu and the superconducting oxide has the formula NBa 2 Cu 3 O 7-y .
- rare earth elements are Y, La, Eu, Gd, Tb, Dy, Hu, Er, Tm, Yb, or Lu.
- the alloy is formed using rapid solidification techniques to provide a homogeneous alloy.
- Formation of superconducting oxides by electrochemical oxidation allows considerable control over the structure, composition, and thickness of the oxide through adjustment of oxidation conditions, e.g., electrolyte composition, temperature, applied voltage or current and duration of oxidation.
- oxidation conditions e.g., electrolyte composition, temperature, applied voltage or current and duration of oxidation.
- the thickness of the superconducting oxide layer formed can be controlled by electrochemically oxidizing until the desired thickness is obtained.
- the Figure is an electrochemical cell.
- an electrochemical cell 10 includes a container 12, an anode 14, a reference electrode 16, a counter electrode 17, a power supply 18, and an electrolyte 20.
- the container 12 is made of an inert material, such as glass.
- the anode 14 is made of an alloy of the precursor metals of the superconducting oxide.
- the precursor metals are present in the stoichiometric proportions of the metals in the target oxide.
- the alloy is homogeneous, i.e., the chemical composition and microstructure of the alley is substantially uniform throughout. Homogeneity is achieved by using standard rapid solidification techniques such as melt spinning or inert gas atomization.
- the surface of the anode should be smooth to achieve a reproducible surface condition; the smoothness can be generated through conventional abrasion or polishing (e.g., electropolishing) methods.
- the alloy may also be degassed in a suitable inert solvent, e.g., cyclohexane.
- the reference electrode 16 provides a reference potential for the applied voltage (or current) used to form the oxide.
- the preferred reference electrode is a high impedence glass electrode such as a saturated calomel electrode.
- the counter electrode completes the electrochemical circuit and allows electric current to pass between itself and the anode.
- Suitable counter electrodes include standard platinum and graphite electrodes.
- the power supply 18 provides a constant voltage to the cell during the oxidation. Where the oxidation is by galvanostatic techniques, a constant current supply is used. Current and voltage metering instruments are incorporated into the power source configuration.
- the electrolyte 20, in which the electrodes are immersed may be aqueous, non-aqueous, or a molten salt, depending upon the alloy composition and desired film characteristics.
- Non-aqueous electrolytes are most preferred.
- suitable aqueous electrolytes include sulphuric acid and sodium hydroxide solutions.
- non-aqueous electrolytes which should be used where oxide formation in the absence of water is desired, includes solvents such as ethanol, ammonia, and acetonitrile.
- the ionic strength of the electrolyte can be increa-rrd by the addition of, e.g., hydrochloric acid.
- molten salt electrolytes are LiCl and Na 2 SO 4 .
- the oxidations events are carried out using standard methods well known to those skilled in the art.
- the potential is kept constant (perferably between 2.5 V and -2.5 V, with respect to the reference electrode), and the current passed by the anode is monitored to follow the rate of oxide formation.
- the current is kept constant (preferably between 10 -1 A and 10 -6 A/cm 2 ) and the anode potential is monitored to follow the rate of oxide formation.
- the cell can also contain a means for temperature control of the electrolyte and a means for regulating the gas content of the eiectrolyte.
- the oxidation can be performed with an open circuit, thereby making a counter electrode unnecessary.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
Disclosed is a method for preparing superconductive oxides by electrochemical oxidation. An electrochemical cell includes an anode made of an alloy of the metallic precursors of the superconducting oxide. A surface of the anode is in contact with an electrolyte of the cell, and the anode is electrochemically oxidized to form the superconducting oxide.
Description
PREPARATION OF SUPERCONDUCTING
OXIDES BY ELECTROCHEMICAL OXIDATION
ANODIC SUPERCONDUCTORS
Background of the Invention
This invention relates to superconducting materials.
Superconductors are materials having zero resistance to the flow of electrons below a certain critical temperature, Tc. It is known that certain metal oxides, e.g., La2-xBaxCuO4-y, La2-xSrxCuO4-y, Ba2YCu2O9-Y, etc. exhibit superconductivity. It is desirable to provide such oxides in forms, e.g., wires or thin films, that permit practical utilization of their superconductive property. Summary of the Invention
In general the invention features preparing a superconducting oxide by electrochemical oxidation. According to the invention, an electrochemical cell containing an anode made of an alloy of the metallic precursors of the superconducting oxide is provided. A surface of the anode is in contact with the electrolyte of the cell, and the anode is electrochemically oxidized to form the superconducting oxide. Preferably the metallic precursors are present in the alloy in the stoicherr.etric proportions of the metals in the oxide.
In some preferred embodiments, the metallic precursors are La, M, and Cu and the superconducting oxide has the formula La2-yMxCuO4-y. M is an alkaline earth element such as Ba, Sr, or Ca.
In other preferred embodiments, the metallic precursors are rare earth elements (N), Ba, and Cu and the superconducting oxide has the formula NBa2Cu3O7-y. Examples of rare earth elements are Y, La, Eu, Gd, Tb, Dy, Hu, Er, Tm, Yb, or Lu.
In other preferred embodiments the alloy is formed using rapid solidification techniques to provide a homogeneous alloy.
Formation of superconducting oxides by electrochemical oxidation allows considerable control over the structure, composition, and thickness of the oxide through adjustment of oxidation conditions, e.g., electrolyte composition, temperature, applied voltage or current and duration of oxidation. For example, because the oxidation proceeds from the outer surface of the anode towards the center of the anode, the thickness of the superconducting oxide layer formed can be controlled by electrochemically oxidizing until the desired thickness is obtained. Other features and advantages of the invention will be apparent from the description of the preferred embodiments thereof, and from the claims.
Description of the Preferred Embodiments
The Figure is an electrochemical cell.
Referring to the Figure, an electrochemical cell 10 includes a container 12, an anode 14, a reference electrode 16, a counter electrode 17, a power supply 18, and an electrolyte 20.
The container 12 is made of an inert material, such as glass.
The anode 14 is made of an alloy of the precursor metals of the superconducting oxide. The precursor metals are present in the stoichiometric proportions of the metals in the target oxide. The alloy is homogeneous, i.e., the chemical composition and microstructure of the alley is substantially uniform throughout. Homogeneity is achieved by using standard rapid solidification techniques such as melt spinning or inert gas atomization. The surface of the anode should
be smooth to achieve a reproducible surface condition; the smoothness can be generated through conventional abrasion or polishing (e.g., electropolishing) methods. The alloy may also be degassed in a suitable inert solvent, e.g., cyclohexane.
The reference electrode 16 provides a reference potential for the applied voltage (or current) used to form the oxide. The preferred reference electrode is a high impedence glass electrode such as a saturated calomel electrode.
The counter electrode completes the electrochemical circuit and allows electric current to pass between itself and the anode. Suitable counter electrodes include standard platinum and graphite electrodes.
For potentiostatic applications, the power supply 18 provides a constant voltage to the cell during the oxidation. Where the oxidation is by galvanostatic techniques, a constant current supply is used. Current and voltage metering instruments are incorporated into the power source configuration.
The electrolyte 20, in which the electrodes are immersed, may be aqueous, non-aqueous, or a molten salt, depending upon the alloy composition and desired film characteristics. Non-aqueous electrolytes are most preferred. Examples of suitable aqueous electrolytes include sulphuric acid and sodium hydroxide solutions. Examples of non-aqueous electrolytes, which should be used where oxide formation in the absence of water is desired, includes solvents such as ethanol, ammonia, and acetonitrile. Where non-aqueous electrolytes are used, the ionic strength of the electrolyte can be increa-rrd by the addition of, e.g., hydrochloric acid. Examples of molten salt electrolytes are LiCl and Na2SO4.
The oxidations events are carried out using standard methods well known to those skilled in the art. In general, for potentiostatic oxidation, the potential is kept constant (perferably between 2.5 V and -2.5 V, with respect to the reference electrode), and the current passed by the anode is monitored to follow the rate of oxide formation. For galvanostatic oxidation, the current is kept constant (preferably between 10-1 A and 10-6 A/cm2) and the anode potential is monitored to follow the rate of oxide formation.
Other Embodiments Other embodiments are within the following claims. For example, the cell can also contain a means for temperature control of the electrolyte and a means for regulating the gas content of the eiectrolyte. Moreover, in a limited number of applications, the oxidation can be performed with an open circuit, thereby making a counter electrode unnecessary.
Claims
1. A method of preparing a superconducting oxide comprising the steps of providing an electrochemical cell comprising an anode having a surface in contact with an electrolyte, said anode comprising an alloy of the metallic precursor of the superconducting oxide to be produced, and electrochemically oxidizing said anode to form said superconducting oxide.
2. The method of claim 1 wherein said metallic precursors comprises La, M, and Cu and said superconducting oxide has the formula
La2-xMxCuO4-y, wherein M is an alkaline earth element.
3, The method of claim 1 wherein said metallic presursors comprises N, Ba, and Cu and said superconducting oxide has the formula NBa2Cu3O7-y, wherein N is a rare-earth element.
4. The method of claim 3 wherein said rare-earth element is selected from the group consisting of La, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu.
5. The method of claim 1 wherein said alloy is formed using rapid solidification processing.
6. The method of claim 1 wherein said metallic precursors are present in said alloy in stoichiorcetric proportions.
7. The method of claim 1 wherein said electrolyte is aqueous, said method further comprising dehydrating said superconducting oxide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US14962188A | 1988-01-28 | 1988-01-28 | |
| US149,621 | 1988-01-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1989007161A1 true WO1989007161A1 (en) | 1989-08-10 |
Family
ID=22531132
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US1989/000308 WO1989007161A1 (en) | 1988-01-28 | 1989-01-25 | Preparation of superconducting oxides by electrochemical oxidation: anodic superconductors |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0400057A4 (en) |
| JP (1) | JPH03503548A (en) |
| WO (1) | WO1989007161A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2655356A1 (en) * | 1989-12-01 | 1991-06-07 | Rhone Poulenc Chimie | Process for electrochemical treatment of a material in oxide form, application to superconductors and superconductors thus obtained |
| EP0434480A1 (en) * | 1989-12-01 | 1991-06-26 | Rhone-Poulenc Chimie | Process of electrochemical treatment of oxide materials |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63291318A (en) * | 1987-05-23 | 1988-11-29 | Fujikura Ltd | Manufacture of oxide superconductive wire |
-
1989
- 1989-01-25 WO PCT/US1989/000308 patent/WO1989007161A1/en not_active Application Discontinuation
- 1989-01-25 JP JP1502483A patent/JPH03503548A/en active Pending
- 1989-01-25 EP EP19890902671 patent/EP0400057A4/en not_active Withdrawn
Non-Patent Citations (1)
| Title |
|---|
| Journal of the Electrochemical Society, Volume 135, No. 6, June 1988, D.B. ZURAWSKI et al, "Towards the Electrochemical Synthesis of High Temperature Supercinductors", pp. 1607-1608 (see entire article). * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2655356A1 (en) * | 1989-12-01 | 1991-06-07 | Rhone Poulenc Chimie | Process for electrochemical treatment of a material in oxide form, application to superconductors and superconductors thus obtained |
| EP0434480A1 (en) * | 1989-12-01 | 1991-06-26 | Rhone-Poulenc Chimie | Process of electrochemical treatment of oxide materials |
| FR2665713A2 (en) * | 1989-12-01 | 1992-02-14 | Rhone Poulenc Chimie | Process for electrochemical treatment of a material in the form of oxide |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0400057A4 (en) | 1990-12-19 |
| EP0400057A1 (en) | 1990-12-05 |
| JPH03503548A (en) | 1991-08-08 |
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