Distribution of inhomogeneities across the ceramic core in monocore (Bi,Pb)-2223/Ag tapes

Monocore (Bi,Pb)-2223 tapes have been made by a sequence of thermomechanical steps involving two-axial and eccentric rolling and annealing for between 20 and 100 h. The purpose of this treatment was to differentiate tapes in texturization degree and phase content allowing for texture and phase development monitoring during the thermomechanical treatment. Texture degrees, phase content and purity were measured by x-ray diffraction (XRD). Results obtained have confirmed different susceptibility to texturization between the two main phases ('high' for 2223 and 'weak' for 2212) and have visualized differences between ceramic at the Ag interface versus core centre. Evidence of a c -axis constant decrease, 2223-phase content and purity increase, higher texturization degree and smaller volume of secondary phases has been found and demonstrated for this interfacial layer. Observed properties are discussed and related to process parameters and the critical current density Jc in final tapes. (author)