Superconducting Cu-Nb<inf>3</inf>Sn composites produced by cold extrusion of fine powders

Abstract

Multifilamentary Cu-Nb composites were produced by cold P/M processing. Elementary powders of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\leq 40 \mu</tex> m diameter were first cold extruded and subsequently drawn to wires or ribbons. Cu-Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn composites were produced by electrochemical Sn plating of the Cu-Nb composite, followed by a reaction annealing at temperatures between 650 and 850°C. After cross-sectional reduction by a factor R = 500, a sample of the composition Cu-30%Nb (20 at%Sn) had a J <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> value of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 12 T, which is comparable to the values obtained by other techniques. This cold P/M technique is adaptable to a wide range of superconducting systems and appears to be promising for industrial applications.