Argonne National Laboratory. Materials and Components Technology Division.
Abstract
Long lengths of flexible Ag-clad Bi-2223 Superconductors have been fabricated by the powder-in-tube technique using prereacted, poly-phase, Pb-doped Bi-Sr-Ca-Cu-O powders. At liquid helium (4.2 K) temperature, improved process conditions yielded transport critical current density (J[sub c]) values greater than 10[sup 5] A/cm[sup 2] at zero field; at liquid nitrogen (77K) temperature, the J[sub c] values of short tape samples exceeded 4 [times] 10[sup 4] A/cm[sub 2]. Rolled tapes are cut into lengths up to 2 - meters long and are used in parallel to fabricate small superconducting pancake coils by the wind-and-react'' technique. The cots are characterized at 77K and 4.2 K. The J[sub c] of the coils are up to 80% of the short, rolled sample result at 77 K. The coils exhibited these results even after being cooled and warmed several times between ambient, 77 K and 4.2 K, indicating their stability following thermal cycling
