Present Status and Future Perspective of Bismuth-Based High-Temperature Superconducting Wires Realizing Application Systems

Among a series of high-temperature superconducting materials that have been discovered to date, (Bi, Pb)(2)Sr2Ca2Cu3O10-x is the best candidate for superconducting wires that are long with commercial productivity, and critical current performance. In particular, the controlled overpressure (CT-OP) sintering technique gave us a 100% density of (Bi,Pb)(2)Sr2Ca2Cu3O10-x portion, which leads to robustness, increase in critical current, and mechanical tolerance. Many application prototypes are already verified and are being evaluated worldwide. Current leads for large magnets and magnetic billet heaters are already commercial products. Commercial applications for power cables, motors for ship propulsion and electric vehicles, and many kinds of magnets are promising in the near future. (C) 2012 The Japan Society of Applied Physics