THE EFFECT OF DEFORMATION REGIMES ON SUPERCONDUCTING PROPERTIES AND MICROSTRUCTURE OF BI-2223 TAPES

The rolling process of Bi-2223 tape conductors was optimized trough th e regressive analysis of experimental data. This procedure ensures the effective densification of the powder precursor in the core and homog eneous distribution of powder density in conductor cross section, thus shortening the rolling process. The Jc values were realized for the m onofilament and 19-filament conductors processed by ''powder in tube'' method with one step intermediate rolling such as 3.1 x 10(4) A/cm(2) (77 K, OT) and 2,6 x 10(4) A/cm(2) (77 K, OT) respectively. Character istics of single pancake coils are presented fabricated from 19-filame nt conductor: no Jc degradation was observed after 10 steps of thermoc ycling in the range between 77 and 293 K.