Recent progress in high-t c superconducting wires and their applications for electric power apparatus

Abstract

The development of superconducting wires is one of the key issues in realizing superconducting equipment. Superconducting wires made of alloys such as NbTi have already been commercialized and applied to MRI and NMR, and superconducting wires made of metal compounds such as Nb 3Sn have been manufactured for use in high-field applications such as accelerators and nuclear fusion. Since a high-T C superconductor (over 77 K) was discovered approximately 25 years ago, it has been expected that they will be used in electric power apparatus such as cables and electricity storage devices. Among the various high-T C superconductors, Bi 2Sr 2Ca 2Cu 3O 10 (Bi2223) and REBa 2C u3O y (RE123) (RE: rare earth elements) have mainly been investigated with aim of producing superconducting wires. Among the other superconductors, MgB 2 superconductors, which are expected to lead to a lower manufacturing cost, and the recently discovered ironbased superconductors are being studied at present. This article is focused on the development of superconducting wires for superconducting electric power apparatus reviewing the recent progress in RE123 and Bi2223 superconducting wires and their applications. © IEICE 2012.