Solder joint part and method for manufacturing the same

A method for manufacturing a solder joint part joining a first metal base material and a second metal base material with solder,

• at least one metal base material of the first metal base material and the second metal base material being an alloy including Ni in an amount of more than 0 wt % and less than 44 wt % and Cu in an amount of more than 56 wt %,
• the solder being one of:
• a solder alloy containing Ga and inevitable impurities;
• [or] and a solder alloy containing Ga as a main component and having a melting point of 30° C. or lower, the method comprising:
• applying the solder to a surface of the first metal base material and placing the second metal base material on the applied solder;
• and
• heating the first metal base material and the second metal base material to a temperature of 90° C. or lower in one of a noble gas atmosphere, an atmospheric air, and a liquid, to generate CuGa2 or (Cu, Ni)Ga2 between the first metal base material and the second metal base material, thereby joining the first metal material and the second metal material.