Properties of Bi(Pb)-2223 precursor powders calcined in reduced oxygen partial pressure

,The : performance of Ag/Bi-2223 superconducting tapes is affected by compl ex processing parameters, especially by the characteristics of the precurso r powder, i.e., the nominal stoichiometry, phase assemblage, purity, partic le size and distribution, etc. Calcination in a low oxygen partial pressure (3 torr oxygen) resulted in a reactive precursor po,,der by the accelerate d decomposition of the carbonates. In addition, the type of second phase an d the distribution of lead in this precursor powder are different compared to those of the powder calcined in atmospheric air. Ag/Bi-2223 tapes have b een fabricated and the phase evolution, critical current density, and micro structure of the two tapes have been compared.