Interface irregularity and texture evolution of Bi-Sr-Ca-Cu-O superconductor tape processed by PIT method

We evaluated the degree of texture and the interface irregularity between t he Ag sheath and the superconductor core of Bi-Sr-Ca-Cu-O (BSCCO) supercond uctor tape during drawing and rolling processes, The degree of texture and the interface irregularity were characterized by pole figure analysis and t he coefficient of variation in thickness (COV) Factor, respectively. It was observed that the interface became gradually irregular during the drawing and rolling processes. On the other hand; the degree of texture improved si gnificantly during rolling process, but little during the drawing process, The critical current of the tape depended remarkably on the combined effect s of the interface irregularity and the degree of texture. As the dimension of the wire/tape was changed from a diameter of 3.25 mm to a thickness of 0.20 mm, the critical current increased by 10 times. Microstructural invest igation showed that grain alignment was Locally degraded by the existence o f both second phases and interface irregularity. It was observed that large r grain size and better texturing developed near the relatively straight in terface compared to those inside the superconducting core.