LONG-LENGTH PROCESSING OF BSCCO-2223 TAPES MADE BY USING AG ALLOYS SHEATH

To improve the smoothness of BSCCO/Ag interface as well as to increase strength and resistivity, we have fabricated various compositions of Ag-Mg alloy, Ag-Au alloy, Ag-Pd-Mg alloy, and Ag-Au-Mg alloy. These sh eath alloys were evaluated for hardness, resistivity, and microstructu re to find out alternative candidate to pure Ag for sheath materials i n powder-in-tube (PIT) processing of BSCCO-2223 tapes. For a long-leng th process, these sheath alloys were extruded into commercial size (OD :12.7mm, ID:9.5mm, 200mm long) of hollow tube, and were investigated f or sausaging effect, microstructure, and compatibility (Ic measurement ) with 2223 BSCCO superconductor during processing. The alloying of Au and Pd increased resistivity but is ndt very effective in increasing hardness. Addition of small quantity of Mg to Ag-Au and Ag-Pd increase d hardness significantly due to dispersion hardening. Microstructural studies of BSCCO-2223/Ag-Au-Mg tapes revealed a more dense and aligned BSCCO structure.