Title :
Fabrication of high-field Nb3Sn conductors from Sn-Ta/Nb composites
Author :
Tachikawa, K. ; Kato, R. ; Aodai, M. ; Izawa, H. ; Takeuchi, T.
Author_Institution :
Fac. of Eng., Tokai Univ., Kanagawa, Japan
fDate :
6/1/2003 12:00:00 AM
Abstract :
The mechanism of thick (Nb,Ta)3Sn layer synthesis in the Ta-Sn core/Nb (Nb-Ta) sheath composite is studied. The diffusion of Nb from the sheath to the core seems to play a key roll to enhance that of Sn from the core to the sheath synthesizing (Nb,Ta)3Sn layer. A simplified powder core process, in which Ta + Sn mixed powder is used instead of Ta-Sn reacted powder as the core, does not degrade the high-field performance of the (Nb,Ta)3Sn conductor. A finer dispersion of Ta in the core is found to improve the Jc of the conductor below 23 T. New Jelly Roll processed (Nb,Ta)3Sn wires are fabricated using Sn-Ta sheets richer in Sn. The JR wires exhibit attractive high-field performance, and a small amount of Cu addition to the Sn-Ta sheet effectively decreases the reaction temperature.
Keywords :
chemical interdiffusion; composite superconductors; critical current density (superconductivity); niobium alloys; powder metallurgy; tantalum alloys; tin alloys; (Nb,Ta)3Sn wire; (NbTa)3Sn; 23 T; A15 phase; Jelly Roll process; Nb3Sn; Nb3Sn high-field superconductor; Sn-Ta/Nb composite; SnTa-Nb; critical current density; diffusion reaction; fabrication process; powder core process; Conductors; Degradation; Fabrication; Magnetic cores; Magnetic fields; Niobium; Optical microscopy; Powders; Tin; Wires;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2003.812347