REACTION INDUCED TEXTURE OF (BI,PB)2SR2CA2CU3O10+DELTA AG COMPOSITE CONDUCTORS/

A considerable body of evidence collected on silver-sheathed (Bi,Pb)2S r2Ca2Cu3O10+delta (Bi-2223/Ag) composite conductors heat treated witho ut any additional rolling or pressing (beyond fabrication of the initi al composite) has revealed that significant texturing of the Bi-2223 g rains occurs as the Bi-2223 formation reaction takes place. During hea t treatment, Bi-2223 is produced via a reaction between Bi-2212 and se cond phases in the core of the composite. As the Bi-2223 forms, it dev elops texture by what appears to be a grain growth mechanism. These co ncurrent processes ultimately result in a well-textured, single-phase conductor even when no additional rolling or pressing is done to the i nitial composite. This observation raises important questions about th e relative contributions of the heat treatment and deformation steps t o texture development during conventional oxide-powder-in-tube process ing of Bi-2223/Ag composite conductors.