Development of Ag-sheathed Bi2223 superconducting wires and their applications

Silver-sheathed multifilamentary BiPbSrCaCuO 2223 superconducting wires with long length and high Jc of over 10(4)A/cm(2) (77.3K, 0T) were developed by using the powder-in-tube method. A scaling law, which can be adopted in a wide temperature and magnetic field range, was found. Using this scaling law, we can estimate Jc at any temperature and magnetic field by using the wire performance at 77K without external field. Low AC loss wires and high strength wires were also developed for future applications. High electrical resistivity of the matrix and the use of twisted filaments are effective for reducing the AC losses. Good stress and strain tolerant characteristics were obtained for silver alloy sheathed wires. As a result of the progress in wire technology, we were able to fabricate many application prototypes. In high amperage conductor applications, current leads, bus bars and cable conductors were developed. In magnet applications, pancake magnets cooled by a GM refrigerator and solid nitrogen, as well as a layer wound magnet for high magnetic field NMR application at 4.2K, were developed.