Composite superconductive wire-material, manufacturing method of composite superconductive wire-material, and superconductive cable

A manufacturing method of a composite superconductive wire-material, which comprises the steps of:

• preparing a composite superconductive wire-material comprising:
• a thin-film superconductive wire-material including:
• a substrate;
• a superconductive layer;
• and a stabilizing layer;
• arranged in this order;
• abutting the thin-film superconductive wire-material and an electroconductive tape to each other;
• immersing at least a part of an abutment area, the abutment area comprising the thin-film superconductive wire-material and the electroconductive tape abutted to each other, into a molten solder in a solder bath to bond the thin-film superconductive wire-material and the electroconductive tape to each other, thereby forming a composite superconductive wire-material bondedly formed by the solder;
• and
• transporting the composite superconductive wire-material to the outside of the solder bath;
• and
• that the solder is a lead-free solder comprising at least Sn and Bi,
• wherein at least the part of the abutment area is immersed into the solder at an immersion temperature between 160° C. and 200° C.;
• and the immersion temperature has a relationship with an immersion time, during which at least the part of the abutment area is immersed into the solder, as follows,
• immersion temperature≧(−10/3)×immersion time+210, where 3 sec≦immersion time≦15 sec, and
• immersion temperature≦(−4/3)×immersion time+280, where 60 sec ≦immersion time ≦90 sec.