Investigation of the initial stages of processing Bi-2223 multifilamentary tapes by analytical electron microscopy

Analytical transmission electron microscopy (TEM) was used to probe the formation of liquid phases in multifilamentary Bi-2223 tapes. Silver was found to nucleate small amounts of liquid phase early in the processing. However, liquid formation was primarily associated with the 14-24 AEC and time at temperature (induction period) was the major factor determining the amounts of lead-rich liquid phase formation in these tapes. The compositions of the lead-rich liquid phases were measured quantitatively. The data presented is consistent with a mechanism whereby Bi-2223 can precipitate from a liquid phase.