# US 4,391,657 A · Manufacture of niobium-aluminum superconducting material

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- Number: US 4,391,657 A
- Document ID: US4391657A
- Status: Granted
- Kind: A
- Application number: 06/284,523
- Filed: 1981-07-17
- Granted: 1983-07-05
- Earliest claimed: 1981-07-17
- Assignees: Bell Telephone Laboratories, Incorporated
- Inventors: William L. Feldmann; John M. Rowell; Paul H. Schmidt
- Web page: https://patentgrep.com/patent/US4391657A

## CPC

- H10N 60/85: Superconducting active materials
- H10N 60/0184: {of devices comprising intermetallic compounds of type A-15, e.g. Nb3Sn}
- Y10S 420/901: Superconductive
- Y10S 505/813: Wire, tape, or film
- Y10S 505/815: Process of making per se
- Y10S 505/818: Coating
- Y10S 505/919: Reactive formation of superconducting intermetallic compound
- Y10T 29/49014: Superconductor
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Niobium-aluminum superconducting wire and other shaped articles are made by heating a precursor body which comprises niobium, an auxiliary element which is more easily oxidizable than aluminum, and aluminum oxide, the aluminum oxide being supported by a surface or a matrix comprising niobium and the auxiliary element. Among suitable auxiliary elements are zirconium, hafnium, scandium, yttrium, and the nonmagnetic rare earths.

## Claims

### Claim 1

Method for making a Nb.sub.3 Al superconducting shaped article which is superconducting at a temperature which is greater than or equal to 10 degrees Kelvin,
said method comprising heating a precursor body consisting essentially of a supporting component and a supported component,
said supporting component comprising a first element which is niobium and at least one additional element whose chemical affinity for oxygen is greater than the chemical affinity between aluminum an oxygen,
said supported component comprising aluminum oxide, and
heating being at a temperature in the range of from 800 to 1600 degrees Celsius and for a time which is sufficient to reduce the aluminum oxide and to form an oxide of at least a portion of said at least one additional element, whereby at least a layer consisting essentially of superconducting niobium-aluminum is formed.

### Claim 2 (depends on 1)

Method of claim 1 in which a substantial portion of said superconducting niobium-aluminum has beta-tungsten structure.

### Claim 3 (depends on 1)

Method of claim 1 in which, in said supporting component, niobium and said at least one additional element are mixed.

### Claim 4 (depends on 1)

Method of claim 1 in which, in said supporting component, niobium and said at least one additional element are alloyed.

### Claim 5 (depends on 1)

Method of claim 1 in which said supported component is essentially a layer on said supporting component.

### Claim 6 (depends on 1)

Method of claim 1 in which said supported component is dispersed in a matrix consisting essentially of said supporting component.

### Claim 7 (depends on 1)

Method of claim 1 in which said supporting component comprises at least one third element.

### Claim 8 (depends on 7)

Method of claim 7 in which said at least one third element is germanium.

### Claim 9 (depends on 1)

Method of claim 1 in which said supported component comprises at least one additional oxide.

### Claim 10 (depends on 9)

Method of claim 9 in which said at least one additional oxide is germanium oxide.

### Claim 11 (depends on 1)

Method of claim 1 in which said superconducting layer has a thickness which is greater than or equal to 1000 Angstroms.

### Claim 12 (depends on 1)

Method of claim 1 in which said precursor body comprises less than 1 atomic percent magnetic elements.

### Claim 13 (depends on 1)

Method of claim 1 in which said precursor body comprises less than 5 atomic percent hydrogen.