The fabrication and properties of Nb<inf>3</inf>Sn superconductors by the solid diffusion process

Abstract

It has been demonstrated that the superconducting compound Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn can be produced at the interface of Nb and a Cu-Sn alloy when the composite is heat treated at the proper reaction temperature. This method of Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn preparation was also shown to be particularly suited to the fabrication of (a) Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn multifilamentary composite wires for dc and low frequency applications and (b) low ac loss Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn tapes for 60 Hz applications. The fabrication method and superconducting properties of Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn composite conductors made by this process are reviewed and the metallurgical aspects of the process are discussed. Since practical applications of these composites requires large, high current conductors, methods of producing compound conductors such as cables and braided ribbons which include strengthening and stabilizing components are also discussed and some preliminary results of high current conductors are presented.