Microstructural and magneto-optical characterization of high J(c) BSCCO-2223/Ag tapes

The phase and microstructural evolution, and critical current density of (B i,Pb)-2223/Ag tapes prepared from a variety of precursor powders have been in,investigated. Correlations between the reaction kinetics, the microstruc ture and the critical current density are developed. A mechanism for the BS CCO-2223 phase formation depending on the precursor phase assemblage is pre sented. Magneto-optical imaging shows that high J(c) samples (J(c)(77K, 0T) similar to 35kA/cm(2)) are well connected longitudinally but strongly sub- divided by longitudinal cracks. The performance of BSCCO-2223 tapes should be further improved by controlling the liquid phase to better heal the crac ks.