A systematic comparison of the phase development in PBSCCO 2223 precursor powders prepared by solid-state processing, co-precipitation, citrate gel and spray pyrolysis.

摘要

PBSCCO 2223 ((Bi,Pb)_2Sr_2Ca_2Cu_3O_10+delta) precursor powders have been prepared by solid-state procesing, co-precipitation, citrate gel and spray pyrolysis. Phase development as a functio nof both the calcination temperature and holding time has been studied; powders synthesised from the different routes undergoing remarkably different phase transformations with temperature. Above 700 deg C, the superconducting Bi-2201 ((Bi,Pb)_2Sr_2Cu_1O_6+delta) phase is found to be the mayor phase present, at 800 deg C the Bi-2212 ((Bi,Pb)_2Sr_2CaCu_2O_8+delta) phase co-exists with minority phases, including Ca_2PbO_4 and cuO. The conversion of the precursors to the PBSCCO 2223 phase has also been followed and reveals that the powders produced from the spray pyrolysis process transform to the PBSCCO 2223 phase far faster than the other powders. Effective control of this fast transformation to the PBSCCO 2223 phase would offer significant advantage in OPIT processing.