Title :
Phase formation and melt textured growth of (Bi,Pb)-Sr-Ca-Cu-O
Author :
Yamada, Y. ; Graf, T. ; Seibt, E. ; Flukiger, R.
Author_Institution :
Kernforschungszentrum Karlsruhe, Inst. fuer Tech. Phys., Germany
fDate :
3/1/1991 12:00:00 AM
Abstract :
A textured structure of (2223) phase in the (Bi,Pb)-Sr-Ca-Cu-O system with grain sizes ⩾200 μm 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 Ca2CuO3 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
Keywords :
bismuth compounds; calcium compounds; crystal growth from melt; grain size; high-temperature superconductors; lead compounds; strontium compounds; Ag-sheathed tapes; BiPbSrCaCuO; Ca2CuO3 segregation; a-b plane parallel; grain sizes; high temperature superconductor; high-volume friction; intermediate precipitates; melt textured growth; rapid cooling; reduced-oxygen atmosphere; slow cooling; volume fraction; Atmosphere; Cooling; Critical current density; Grain size; Heat treatment; Powders; Superconducting films; Superconducting magnets; Superconductivity; Temperature;
Journal_Title :
Magnetics, IEEE Transactions on
