Superconducting Joint of Y-Ba-Cu-O Using Various Superconducting Solders

Two blocks of single grain Y-Ba-Cu-O superconductors were welded with various solder materials that have lower decomposition temperature than that of Y-Ba-Cu-O superconductors. Microstructural analyses revealed that no segregation of the secondary phase and/or the residual liquid phase was observed at the joint when the (110) surfaces were directed parallel to the welded region. We also found that Y-Ba-Cu-O joined with a sintered Y-Ba-Cu-O/Ag bar exhibited the strongest coupling.