High electrical performance Ag-sheathed Bi-2223 multifilamentary tapes prepared by an optimised PIT processing route

An optimised PIT processing route is introduced and discussed, using results from experiments investigating the effect of processing on microstructure, and subsequently on J/sub c/ in PIT tapes. At 77 K and self-field, the highest J/sub c/ performance of 51000A/cm/sup 2/ has been obtained for 69-filament tapes. High critical current samples with I/sub c/=108A and J/sub c/=36000A/cm/sup 2/ have been measured at 77 K and self-field for 361-filament tapes. Our results indicated that J/sub c/ is influenced by the Pb distribution of Pb-2212, phase composition for the precursor powder, the deformation reduction rate, and the core thickness. Intermediate processing (cooling, deformation and heating) between thermal-mechanical cycles and finally cooling procedures also play an important role on Bi-2223 phase purity and achievement of such high electrical performance in the tapes.