Reaction for high performance (Bi,Pb).sub.2 Sr.sub.2 Ca.sub.2 Cu. sub.3 O. sub.y composites

摘要

The present invention provides a (Bi,Pb)SCCO-2223 oxide superconductor composite which exhibits improved critical current density and critical current density retention in the presence of magnetic fields. Retention of critical current density in 0.1 T fields (77 K, ab plane) of greater than 35% is disclosed. Significant improvements in oxide superconductor wire current carrying capacity in a magnetic field are obtained by subjecting the oxide superconductor composite to a post- processing heat treatment which reduces the amount of lead in the (Bi,Pb) SCCO-2223 phase and forms a lead-rich non- superconducting phase. The heat treatment is carried out under conditions which localize the lead- rich phase at high energy sites in the composite.