Fabrication and properties of high-T/sub c/ tapes and coils made from silver-clad Bi-2223 superconductors

Long lengths of flexible silver-cell Bi-2223 high-T/sub c/ (critical temperature) superconductors have been fabricated by the powder-in-tube technique. By improving process conditions DC transport measurement at liquid helium (4.2 K) and hydrogen (20 K) temperatures yield J/sub c/'s (critical current densities) greater than 10/sup 5/ A/cm/sup 2/ at zero field and exceed 3*10/sup 4/ A/cm/sup 2/ at liquid nitrogen (77 K) temperature in short tape samples. Detailed microstructural analysis and J/sub c/ measurements with applied fields up to 20 T are reported. Coils have been fabricated from 1-m lengths of conductor with J/sub c/'s at 77 K approaching 10/sup 4/ A/cm/sup 2/. Measurements on small pancake coils made from 10-m tapes are also reported.<
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