IMPORTANT PARAMETERS FOR PROCESSING LONG LENGTHS OF AG-SHEATHED BI2SR2CACU2OX CONDUCTORS

The key issues that limit the critical current density across the enti re length of long Ag-sheathed Bi2Sr2CaCu2Ox conductors are identified. They are bubbling of the Ag sheath and nonuniform distribution of non superconducting phases throughout the conductor. The causes of bubblin g are identified and methods to eliminate bubbling are discussed. The microstructure of Ag-sheathed conductors fully processed in atmosphere s with different pO(2) are summarized. The most homogeneous microstruc tures are for tapes made with powder of composition 2.1:2:1:1.95 that is processed in 0.4 to 1 atm O-2.