A new method for joining of Bi(2223)/Ag tapes

A superconducting joint between Bi(2223)/Ag-sheathed tapes has been fabricated with approximately 90% of the current capacity of the tape itself. The silver sheath was mechanically or chemically removed from one side of each tape without disturbing the superconducting core. The exposed superconducting cores of the two tapes are brought into contact, wrapped up with a thin silver foil, and pressed so as to again seal the superconductor in a silver sheath. Then a series of different reaction anneal and mechanical treatments were performed on the joined tapes to obtain an optimum heat-treatment condition. The optical micrographs of a longitudinal section of the entire joint shows that there is no constriction of the superconducting core throughout the joint.