PURPOSE: To provide a high strength oxide superconductive wire rod capable of withstanding the stress due to a self magnetic field in high intensity magnetic field.
CONSTITUTION: A composite tube (a sheath material) as shown by the following (1) and (2), and a manufacturing method for a superconductive wire as shown by the following (3) are provided: (1) A composite tube 3 for manufacturing an oxide superconductive wire whose inner layer 1 is made of Ag, the external layer 2 made of an alloy consisting of Ni and Ag, and the Ni content of the Ag-Ni alloy in the external layer satisfies expression I; 4.6 (1+S)/S≤Ni (at. %)≤15. (2) A composite tube 3 for manufacturing an oxide superconductive wire whose inner layer 1 is made of Ag, the inner layer 2 made of an alloy consisting of Cr and Ag, and the Cr content of the Ag-Cr alloy in the external layer satisfies expression II; 5.6 (1+S)/S≤Cr (at. %)≤18. (3) A manufacturing method for a superconductive wire comprising the steps; The composite tube 3 as shown by (1) or (2) is used to fill a calcined Bi-based superconductor powder therein, followed by drawing, then cold rolled followed by heat- treatment at the temperature of 830-890°C. In the expressions I and II, S represents a clad ratio and is the ratio of So relative to the cross-sectional area Si of the inner layer as shown in the figure, that is So/Si.
Shunichi Nishida
Fukushima Kensuke
Akihiko Endo
