Effect of sintering temperature on phase composition and Jc of Ag-sheathed Bi-2223 single and multifilamentary tapes

摘要

The sintering temperature window of Ag sheathed Bi-2223 tapes was studied by a temperature gradient method for fabrication of tapes. The I c of the tapes was found to be very sensitive to the sintering temperature. For the single filament tapes, the Ic reaches the maximum value at a temperature higher than that at which the 2212 percentage reaches the minimum. Around 6.5% of 2212 still exists in the best single filamentary tapes, while just a half of this 2212 fraction (about 3.5%) remains in the best 19 filamentary tapes. The J c was found to be more sensitive to Bi-2212 phase content in the multifilamentary tapes than that in the single core tapes. A Jc of 4.5×104 A/cm2 (Jc 1×104 A/cm2) for single core tapes and of 3.3×104 A/cm2 (Jc 0.65×10 4 A/cm2) for 19 core multifilament tapes were achieved reproducibly with sintering time of 100 hours and one intermediate pressing. 70% of maximum Ic can be retained within 4 degrees sintering temperature window for both single and 19 filamentary tapes