Method fabricates stabilized composite conductor, for use in construction of magnets, using equal amounts of superconducting and metal materials, thus reducing weight, cost and size

Gavaler, J. R.

Jones, C. K.

English

NASA Technical Reports Server

August 1972	 B72-10465 
NASA TECH BRIEF 
NASA Headquarters 
NASA Tech Briefs announce now technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Magnets with Stabilized Conductors 
The problem: 
In the fabrication of large superconducting magnets, 
the high percentage of metal used to overcome instability 
(flux movement) is very costly. In a typical composite 
superconducting coil, the amount of metal used is about 
100 times that of the superconductor material. 
The solution: 
A method has been developed to fabricate a stabilized 
composite conductor (for use in the construction of 
magnets) using equal amounts of superconducting and 
metal materials, thus reducing the weight, cost, and size. 
How it's done: 
A composite conductor is fabricated by preparing 
individual thin layers of a superconducting material 
(niobium nitride) and a high purity normal metal 
(copper). These layers are deposited on an appropriate 
substrate (stainless steel) in an alternate fashion. Super-
conducting films having excellent conducting properties 
are produced down to a thickness of about 200 x 108 
cm. Once a layer of this film has been deposited on a 
substrate, a second layer consisting of a metal (having the 
desired electrical and thermal characteristics) is embedded 
onto the film. Alternate layers are then deposited until a 
sufficient thickness is achieved, which yields the desired 
current carrying properties. 
When a magnet is in use, it is found that instability 
(flux motion) results in short sections of the super-
conducting solenoid becoming resistive, and the heat 
generated by passing currents through these resistive 
sections results in the loss of superconductivity in the 
magnet.
Use of very thin superconductor layers restricts the 
movement of flux and eliminates the fundamental 
cause of magnet instability. Even if flux motion did occur, 
the growth of the stabilizing normal metal onto the super-
conductor presents a low, thermal resistance interface 
between the two materials. Any excessive heating 
generated by flux motion is dissipated. 
This composite conductor, when used in the windings 
of magnets or in rotating machinery, minimizes or 
eliminates the problems of instability that now exist. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
NASA Headquarters 
Code KT 
Washington, D.C. 20546 
Reference: TSP72-10465 
Patent status: 
Title to this invention has been waived under the 
provisions of the National Aeronautics and Space Act 
[42 V.S.C. 2457 (P)], to the Westinghouse Electric 
Corporation, Pittsburgh, Pennsylvania. 
Source: C. K. Jones and J. R. Gavaler of

Westinghouse Electric Corp. 
under contract to

NASA Headquarters
(HQN- 10727) 
r
	
Category 04, 03 
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Aeronautics and Space Administration. Neither the United States	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately owned rights.
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Magnets with stabilized conductors

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