| 摘要 |
PROBLEM TO BE SOLVED: To suppress the damage of an oxidized film by handling and minimize the AC loss by providing an oxidized film layer having a prescribed thickness on an aluminum layer of surface skin. SOLUTION: In a superconductor formed by stranding a plurality of superconductive element wires having a surface skin formed of aluminum, an oxidized film layer having a thickness of 0.1-10μm is provided on the aluminum layer. This film is formed in the stage of element wires or after they are stranded into a stranded wire by means of chemical film processing, anode oxidation, heating oxidation in atmosphere, or oxidation in hot water. Since a stable insulating resistance value is thus obtained, the effect of reducing AC loss can be sufficiently exhibited, and the current distribution of the element wires is uniformed so that a large current can be carried to the superconductive coil. Further, the surface can be also sufficiently protected because of its high hardness. The superconductive stranded wire having the oxidized film layer provided thereon is preferably formed of a rectangular stranded wire, or a multiple stranded wire in which the stranded wire is repeatedly stranded a plurality of times.
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