Connection structure of high temperature superconducting wires, method for forming same, high temperature superconducting wire, and high temperature superconducting coil

A formation method of a connection structure of high temperature superconducting wires, the method comprising:

• a coating film formation step of forming a coating film by coating an organometallic solution containing a metal forming a superconducting connection portion and allowing to dry, on a surface portion of an exposed oxide superconducting layer by separating a part of protective layers of each of a first superconducting wire and a second superconducting wire, which are two high temperature superconducting wires respectively having a band-shaped base material consisting of metal or alloy, the oxide superconducting layer formed on a surface side of the base material, and the protective layer formed on a surface of the oxide superconducting layer;
• a pre-calcining step of forming a pre-calcined film by heating the coating film to a first temperature;
• and
• a main calcining step of forming a superconducting connection portion between the first superconducting wire and the second superconducting wire, by bringing surfaces of the pre-calcined films of the first superconducting wire and the second superconducting wire on which the pre-calcined films are formed into contact in a positional relationship facing each other, and heating to a second temperature which is higher than the first temperature, and forming a joint portion which joins the first superconducting wire and the second superconducting wire by the superconducting connection portion,
• wherein, in the base material of at least one superconducting wire among the first superconducting wire and the second superconducting wire, a first portion constituting the joint portion is thicker than a second portion not constituting the joint portion in the same base material, at least prior to performing the main calcining step.