Reduction in secondary phases and increased transport I/sub c/ of (Bi,Pb)2223/Ag tapes sintered with rapid heating rates

In a two-step heat treatment with one intermediate rolling the final transport critical current, (I/sub c/ at 77 K, self field, 1iV/cm), of 37 filament (Bi,Pb)2223/Ag tapes increases linearly with the heating ramp rate: 20 A to 40 A, ( ~20,000 Acm/sup -2/), for 20(degree)C/hour to 400(degree)C/hour. The principle benefit of the rapid ramp rate is likely to come from ramping fast though 800(degree)C to 832(degree)C in the 1st heat treatment. SEM and XRD analysis on the superconductor-Ag interface show a decrease in the amount of secondary phases, Cu/sub 2/O, Bi/sub 2/(Sr,Ca)/sub 2/Cu/sub 1/O/sub x/, Bi(Sr,Ca)O/sub x/, with increasing ramp rate and critical current.