Hot isostatically pressed Bi2Sr2Ca2Cu3O10 coils made with novel precursors

HIPPING in an autoclave has the potential for closing the cracks in coiled Ag clad superconductor tapes through densification and sintering. Bi2Sr2Ca2Cu3O10 (Bi2223) poses problems, however, because of the narrow temperature window (about 5 C) required for reaction from a competing family of compounds. It is therefore necessary to find precursors that speed up the reaction rate to provide near equilibrium products in a reasonable time without repeated grinding. This letter reports on Bi2223 coil HIPPING experiments with novel precursors in various environments. It is concluded that this technique can successfully restore Jc in Ag-clad tapes of Bi2223. In addition, it was showed that the formation temperatures, from both starting powders and precursors are very dependent on the partial pressures of O2 and N2 and this must be taken into account. 11 refs.