Increased Superconducting Critical Current Density in Internal Tin Niobium-Tin (Nb3Sn) Composite Wires by Magnesium Doping

  • J. C. McKinnell
  • M. B. Siddall
  • P. M. O’Larey
  • D. B. Smathers
Part of the An International Cryogenic Materials Conference Publication book series (ACRE, volume 40)


Requirements for AC superconducting machines such as ITER, MagLev, and power applications continue to drive the development of superconducting wires. There are several challenges in producing wire with good properties for AC applications. Nb-Ti composite wires have been manufactured with sub-micron filaments, often at the cost of a significant reduction in the critical current density (Jc).1 For Nb3Sn wire, the physical filament diameter (d) is often much smaller than the effective filament diameter (deff) due to coupling of the filaments during the reaction heat treatment. Filament coupling causes significant increases in the cooling load per cycle relative to uncoupled filaments. The increase in power dissipation per cycle may affect the magnet stability and in the case of cable in conduit conductors it may shorten the length of cable cooled by a single helium inlet.


Critical Current Density United States Patent Electromagnetic Test Composite Wire Nb3Sn Layer 
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Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • J. C. McKinnell
    • 1
  • M. B. Siddall
    • 1
  • P. M. O’Larey
    • 1
  • D. B. Smathers
    • 1
  1. 1.Teledyne Wah Chang-AlbanyAlbanyUSA

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