Influence of Precursor Powder Fabrication Methods on the Superconducting Properties of Bi-2223 Tapes

Bi-2223 precursor powders are prepared by both oxalate co-precipitation (CP) and spray pyrolysis (SP) methods. The influence of fabrication methods on the superconducting properties of Bi-2223 tapes are systematically studied. Compared to the CP method, SP powder exhibits spherical particle before calcination and smaller particle size after calcinations with more uniform chemical composition, which leads to a lower reaction temperature during calcination process for Bi-2223 tapes. Meanwhile, the non-superconducting phases in SP powder are more uniformly distributed with smaller particle sizes. These features result in finer homogeneity of critical current in large-length of Bi-2223 tape, higher density of filaments and better texture after heat treatment. Therefore, the SP method could be considered as a better route to prepare precursor powder for large-length Bi-2223 tape fabrication.