Furukawa Electric Review No.55Development of Cu-Nb Reinforced Nb₃Sn Wires

Masahiro Sugimoto, Ryo Taniguchi, Koichi Ebisawa, Ka Kei Mun, Hiroyuki Fukushima, Kengo Nakao, Hidekazu Hara, Kiyoshige Hirose, Hirokazu Tsubouchi

We have developed Nb-rod method Cu-Nb reinforced Nb₃Sn wires (Cu-Nb/Nb₃Sn wires), which have significantly improved superconducting characteristics under mechanical stress compared to conventional Nb₃Sn wires. Cu-Nb/Nb₃Sn wires can be manufactured into coils not only with the conventional wind-and-react (W&R) method but also with the react-and-wind (R&W) method, and the superconducting performance and the mechanical characteristics are both improved by a strain control through pre-bending treatment. Furthermore, elemental technology developments for a higher strength, a higher critical current density, a rectangularization, an enamel coating, a thinner wire for small radius bending, and a stranded wire have made them practical wires with an excellent manufacturability. In the future, Cu-Nb/Nb₃Sn wires will be expected to be applied in advanced superconducting equipment such as a high magnetic field NMR/MRI, a particle accelerator, and a large fusion reactor.