Development of (Nb, Ti)3 Sn and Nb-Ti conductors for 15 T superconducting magnet of 40 T class hybrid magnet

Materials for classical and high- superconducting tapes and wires at 4.2 K

“…The highest magnetic field value produced by an Nb 3 Sn magnet is actually 21.8 T at T = 1.8 K. Various methods are used for the industrial fabrication of Nb 3 Sn multifilamentary wires: (a) bronze route, by VAC (Germany) [1], Kobe Steel (Japan) [2], Hitachi (Japan) [3], Furukawa (Japan) [4] and Kurchatov Institute, (b) internal Sn route (separate filaments), by IGC (USA) [7], Alsthom (France) and Eurometalli (Italy) [8], (c) internal Sn route (jelly roll), by TWC (USA)/Oxford (USA) [6], (d) Nb tube technique, by Showa (Japan) [9], (e) NbSn 2 route, by SMI (Netherlands) [10] and (f) Nb 6 Sn 5 compound route (Tokai University, Japan) [11]. The observed difference in j c for the various methods is essentially due to the total amount of Sn in the wire, which varies from 13.5 wt% (bronze route) to >30 wt.% (NbSn 2 route), as indicated in table 1.…”

“…The effect of various additives on j c is shown in figure 1. At 4.2 K and 20 T, the known j c values are 100-130 A mm −2 for the bronze route [1][2][3]7], 150-180 A mm −2 for the internal Sn route [6][7][8], 230 A mm −2 for the Nb tube route [9], >230 A mm −2 for the NbSn 2 route [10] and 320 A mm −2 for the Nb 6 Sn 5 route [11], j c scaling with the total Sn content.…”