Fabrication of BSCCO Tube by Centrifugal Melting Process

Bi-22l2 tubes for fault current limiter (FCL) were fabricated by centrifugal melting process. SrSO4 (10 wt. %) was added to Bi-2212 powder to lower the melting point of Bi-22l2 and to improve the mechanical properties. The BSCCO powder was completely melted at 1300 degree C using the RF furnace and then poured into rotating steel mold. The steel mold, preheated at 450 degree C - 550 degree C for 2 hour was rotated at 1020 - 2520 RPM. The solidified BSCCO tube was cooled down to room temperature in the furnace for 48 hours and separated from the mold between Bi-2212 and the mold. ZrO2 solution was used to separate it easily from the mold and Ag tape was attached in the mold inner wall of the mold to analysis electrical property. Bi-22l2 tube was often cracked when the cooling rate was high. BSCCO tubes with 70 φ x 100 mm, 50 φ x 100 mm and 30 φ x 150 mm size were fabricated by centrifugal melting process. The Jc3 of tubes with 50 φ x 100 mm x 4.0 t and 50 φ x 100 mm x 4.0 t were 178 and 74.2 A/cm2 at 77K, respectively. The processing condition for Bi-2212 tube fabrication was investigated using XRD and SEM analyses.