Fabrication and characterization of BSCCO-2212 tube prepared by centrifugal casting

We fabricated a BSCCO-2212 (2212) tube by the centrifugal casting process for the application in a fault current limiter and evaluated the effect of the processing variables on its microstructure and superconducting properties. Specifically, the effects of the preheating temperatures of the mold and the rotating ingot in the mold on the microstructure, texture, and critical current (I_c) were characterized. We observed that the formability of the tube was dependent on the mold temperature and the optimum temperature was found to be 500-600 °C. When the ingot was annealed at 800 °C for 120 h, the I_c was measured to be 378-450 A at 77 K. To improve the I_c value still further, we modified the centrifugal casting method such that the ingot was rotated in the mold at 870-880 °C, followed by annealing. The I_c of the tube was increased to 678-820 A and this improvement was probably due to its larger grain size and more preferred orientation based on the pole-figure and SEM analyses.