Superconducting joint between Bi-Pb-Sr-Ca-Cu-O superconductor tapes

We evaluated the effects of joining processes such as contact method, shape of joined area and pressure on the electrical and mechanical properties of Bi-2223 superconducting tape. Specifically, the current carrying capacity and bonding strength of the lap-joined tape were measured as a function of uniaxial pressure and correlated to the microstructural evolution. It was observed that the current carrying capacity was reduced in the transition region of the jointed tape and was significantly dependent on the uniaxial pressure. The jointed tape, fabricated with a pressure of 1,600 MPa, showed the highest value of current capacity 90% of the tape itself. It is believed that the highest value of current capacity results from improvements in core density, contacting area and grain alignment. In addition, bonding strength of the jointed tape was evaluated and correlated to the microstructural evolution.