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

We have studied the effect of wire drawing and cold rolling on the texture development of precursor (Bi,Pb)₂Sr₂CaCu₂0_x (2212) phase and its influence on the subsequent (Bi,Pb)₂Sr₂Ca₂Cu₃0_y (2223) phase texture in Ag-clad tapes. A mixture of (Bi,Pb)₂Cu0₄ 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= I(OOS)/[I(OO8)+I(115)] at various oxide filament thickness. Wires containing powder reacted to the 2212 phase prior to loading into a Ag tube had F_{2212≈0.3 after drawing. This texture increased to F2212=0.7 upon rolling. Two other composites reacted to the 2212 phase immediately after drawing, and after being drawn and partially rolled, had worse initial textures, but improved during rolling to FzZl2≈0.7. Samples reacted to 2212 after rolling was complete had F2212≈0.35. The results indicate that the 2212 texture reaches a maximum value of F2212≈0.7 and remains at that level upon subsequent rolling. Samples of filament thickness ≈80 μm were then reacted to form 2223. For the samples which contained 2212 that had received at least some mechanical deformation, the 2223 phase formed with a texture factor F2223 > 0.9, while the tape that contained 2212 formed after rolling developed a 2223 texture of only F2223≈0.75. The results show that there is a substantial texture enhancement upon reaction to 2223, which could be the result of either the 2223 formation mechanism or geometrically constrained grain growth.}