The effect of wire drawing and cold rolling on the precursor 2212 phase texture and its subsequent influence on the (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ texture in Ag-clad tapes

Abstract

Abstract-We have studied the effect of wire drawing and cold rolling on the texture development of precursor (Bi,Pb)2Sr2CaCu20, (2212) phase and its influence on the subsequent (Bi,Pb)2Sr2Ca2Cu30, (2223) phase texture in Ag-clad tapes. A mixture of (Bi,Pb)zCu04 and SrCaCu03 powders having an overall 2223 composition was reacted to form the 2212 phase at different stages of deformation. X-ray diffraction peak height analysis was used to quantify the 2212 texture F2212=

Fabrication and characterization of green-state Bi-2212 ribbons

“…Each of these attempts has been carried out with the hopes of reducing the porosity within heat treated conductors, as well as enhancing the connectivity of the conductors. The current work differs from these previous efforts in that the continuous length roll processed ribbons texture and densify loose powder, while examples from the literature are focused on composite conductors [11,12], texturing Bi-2212 as a precursor to Bi-2223 tapes [13], or to alter texture during melt processing [14,15]. Improvements in both density and texture are thought to enhance J c within the non-silver portion of the conductors by creating a more uniform microstructure within the filaments.…”

Optimal reduction in rolling Ag-sheathed Bi-2223 multifilamentary tapes

“…The texture of the filaments also influences the current carrying capabilities [9,17]. The alignment of the Bi-2212 precursor powder influences the formation of the texture of 2223 phase during later annealing [16][17][18]. In our IR deformation procedure, we increase the shear stress on the oxide core gradually in order to allow powder to flow freely; this made the IR tape have better textured filaments after final mechanical deformation.…”

Heating rate effect on the evolution of texture in (Bi,Pb)2Sr2Ca2Cu3O10Ag-sheathed tapes

“…The thickness of this textured layer is however limited to a few micrometres [6][7][8]. On the other hand, within the bulk of the ceramic core, the Bi2223 grains inherit the average texture of the (Bi, Pb) 2 Sr 2 CaCu 2 O 8 (Bi2212) precursor material as a result of their formation and growth under geometrical constraints via a transient liquid phase [9][10][11]. It is therefore crucial to optimize the preferential orientation of the Bi2212 phase present in the precursor powders prior to the formation of Bi2223.…”

“…The deformation from wire to tape geometry is usually performed by rolling. This process induces a texturing of the Bi2212 plate-shaped grains [1,3,9,12,13] in spite of the extended milling resulting from the strains acting on the ceramic core [14,15].…”