Electrical and mechanical properties of Bi-2223/Ag/barrier/Ag composite tapes

Bi-2223/Ag/barrier/Ag single-core tapes with various oxide barrier material s (BaZrO3, SrCO3, ZrO2 and Al2O3) have been prepared by PIT. The I-V curves and ac susceptibility measurements have been performed for tapes with iden tical heat treatment history. Young's moduli of these tape samples have bee n evaluated by three-point bending and the structure of barrier powders and BSCCO cores was analysed by SEM and XRD, respectively. It was found that t he shape of I-V curves, the current transfer lengths and the mechanical pro perties of tapes are all affected by the oxide barrier type and the barrier thickness, as well as by its porosity and uniformity This is because the o xide barrier controls the oxygen diffusion during the tape heat treatment a nd simultaneously the HTS phase formation kinetics, its purity and content within the superconducting core. On the base of the results obtained for si ngle-core tapes, two kinds of multifilamentary composite were made and test ed.