Influence of silver cladding on the formation and alignment of the (Bi2−<i>x</i>Pb<i>x</i>)Sr2Ca2Cu3O10+δ phase

Abstract

Cross-section transmission electron microscopy was used to investigate the interaction of silver with (Bi,Pb)-Sr-Ca-Cu-O phases during the formation of (Bi2−xPbx)Sr2Ca2Cu3O10+δ (Bi-2223) in a silver-sheathed wire containing a powder composed of (Bi,Pb)2Sr2CaCu2O8+δ (Bi-2212) plus second phases. Observations of the interfacial regions of samples quenched at different stages of conversion revealed that (1) Bi-2212 is initially in direct contact with silver, with the (001) planes parallel to the interface; (2) an amorphous layer between Bi-2212 and silver appears during the induction period that precedes the conversion reaction; and (3) Bi-2223 is detected at the silver/powder interface hundreds of minutes before it begins to appear in regions of the powder away from the interface. The implications of these results are presented and discussed.