Improved J(c) of multifilamentary Bi,Pb(2223)/Ag tapes by periodic pressing

Critical current densities of multifilamentary Ag-sheathed Bi(2223) tapes u p to about 35 000 A/cm(2) have been achieved at 77 K and self field for len gths of several meters using an improved route: Periodic Pressing. This cor responds to an increase by 30-40 % compared to the values obtained for conv entionally roiled tapes starting from the same powders. Several pressing st eps have been introduced during the anneal instead of the only standard rol ling step (based on previous studies performed on both mono- and multifilam entary tapes). In contrast to earlier attempts by pressing techniques, Peri odic Pressing is a practical and scaleable process for the fabrication of l ong lengths of Bi(2223) conductor as the standard intermediate rolling step . Engineering critical current densities of 8 000 A/cm(2) have successfully been obtained for tapes with high filling factor (35%).