Phase formation and melt textured growth of (Bi,Pb)-Sr-Ca-Cu-O

Abstract

A textured structure of (2223) phase in the (Bi,Pb)-Sr-Ca-Cu-O system with grain sizes >or=200 mu m was successfully obtained by melt-textured growth using Ag-sheathed tapes and a reduced-oxygen atmosphere. The (2223) phase occupied more than 80% in volume fraction and was oriented within the a-b plane parallel to the tape flat surface. This high-volume friction was achieved by suppressing the Ca/sub 2/CuO/sub 3/ segregation which prevents homogeneous reaction. Melting, rapid cooling, and slow cooling in the present process were found to have a crucial effect on the complete mixing of the elements, suppressing the intermediate precipitates and promoting the crystal orientation, respectively. Consequently, this resulted in the oriented (2223) phase with grain sizes up to several hundred microns.