TEXTURED BSCCO/AG SUPERCONDUCTING MICROCOMPOSITES WITH IMPROVED CRITICAL CURRENT-DENSITY THROUGH MECHANICAL DEFORMATION

Mechanical deformation has been used to produce BSCCO/Ag superconducting microcomposite ribbons with a c-axis-oriented texture and greatly improved critical current density, J(c). Melt-spun precursor ribbons were oxidized and annealed to produce a well developed '2223' phase, then subjected to mechanical deformation and annealing to produce a textured microstructure. Superconducting BSCCO/Ag ribbons with T(R=O) = 104-110 K and J(c(77)) of 4000-10 000 A cm-2 have been produced by this method. The Lotgering factor, F, was measured by x-ray diffraction to determine the degree of c-direction texture of the '2223' phase. J(c) in a magnetic field was measured to study the effect of microstructural texturing on the field dependence of J(c). This study concentrated on the interrelations between the deformation processes, the degree of c-axis texturing and J(c). Microstructural observation and electron probe microanalysis were also performed to study the relationships between the processing parameters, microstructure and transport properties. The chemical composition and annealing conditions were optimized to maximize the quantity of the '2223' phase, to reduce the amount of the non-superconducting Ca- and Cu-rich phases, and to produce a high degree of texture.