Precursor for a Nb₃Sn superconductor wire, method for manufacturing the same, Nb₃Sn superconductor wire, and superconducting magnet system

摘要

A precursor for a Nb3Sn superconductor wire to be manufactured by the internal diffusion method. The precursor includes Nb-based single core wires, Sn-based single core wires, and a cylindrical diffusion barrier made of Ta or Nb. Each Nb-based single core wire includes a Nb-based core coated with a Cu-based coating made of a Cu-based matrix. Each Sn-based single core wire includes a Sn-based core coated with a Cu-based coating made of a Cu-based matrix. The Nb-based single core wires and the Sn-based single core wires are regularly disposed in the diffusion barrier. The Nb-based single core wires includes at least two kinds of Nb-based single core wires having different Cu/Nb ratios and the Cu/Nb ratio is a cross sectional area ratio of the Cu-based coating to the Nb-based core.

主权项

1. A method for manufacturing a precursor for a Nb3Sn superconductor wire, said method comprising:
coating a Nb-based core with a Cu-based matrix to provide a plurality of Nb-based single core wires; coating a Sn-based core with a Cu-based matrix to provide a plurality of Sn-based single core wires; inserting the plurality of Nb-based single core wires and the plurality of Sn-based single core wires that are bundled regularly into a cylindrical diffusion barrier comprising Ta or Nb; and inserting a bulk comprising the plurality of Nb-based single core wires, the plurality of Sn-based single core wires and the diffusion barrier into a Cu-tube, wherein the plurality of Nb-based single core wires comprises Nb-based single core wires having a Cu/Nb ratio of 0.4 or more and Nb-based single core wires having a Cu/Nb ratio of less than 0.4, wherein the Cu/Nb ratio is a cross sectional area ratio of the Cu-based coating to the Nb-based core, and wherein a diameter of a region, in which the Nb-based single core wires having the Cu/Nb ratio of less than 0.4 are adjacent to each other, is 300 μm or less.