Progress towards a long length metallic precursor process for multifilament Bi-2223 composite superconductors

A process based on metal precursors has been developed for fabricating 361-filament Bi-2223 oxide superconductor-silver composite tapes with oxide and whole wire critical current densities of 20.8 kA/cm/sup 2/ and 3.74 kA/cm/sup 2/ at 77 K over 85 m (1 /spl mu/V/cm criterion). Fabrication of approximately 50 m lengths for a cumulative 1 km yielded average oxide critical current densities of 15.2 kA/cm/sup 2/ and 11.9 kA/cm/sup 2/ using 1 /spl mu/V/cm and 10/sup -11/ /spl Omega/ cm criteria. Within tape I/sub c/ variability was less than 5% except for I/sub c/ drop-offs near the tape ends. The oxide superconductor exhibited a high degree of the required texture. A 1.12 T (at 4.2 K) instrumented magnet with a 2.5 cm bore was fabricated by a react- and-wind approach from the tapes and delivered to Oak Ridge National Laboratory for quench studies.<
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