Explosive Consolidation of (Bi, Pb)-Sr-Ca-Cu-0 Superconductor Powders
Superconducting (2212 phase) Bi-Sr-Ca-Cu-0 (BSCCO) and BSCCO-Ag composites were explosively consolidated in silver tubing and then drawn and rolled into tapes. These silver-sheathed tapes were then subjected to repeated cycles of pressing and heat treatment, which resulted in enhanced texturing and grain growth and a subsequent increase in critical current density (Jc). The effect of Ag powder additions to the superconducting powder further increased texturing and Jc, with optimal properties occurring with 10 vol.% silver powder additions. Scanning electron microscopy indicated that grain alignment increased and grain structure became refined after the thermomechanical treatment. X-ray diffraction studies indicated that grain orientation and conversion of 2212 phase to 2223 phase are improved when explosive consolidation is introduced before the drawing step in the powder-in-tube process.