Development of Ti-sheathed MgB₂wires with high critical current density

Abstract

Working towards developing lightweight superconducting magnets for future space and other applications, we have successfully fabricated mono-core Ti-sheathed MgB 2 wires by the powder-in-tube method. The wires were characterized by magnetization, electrical resistivity, x-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry measurements. The results indicate that the Ti sheath does not react with the magnesium and boron, and the present wire rolling process can produce MgB 2 wires with a superconducting volume fraction of at least 64% in the core. Using the Bean model, it was found that at 5 K, the magnetic critical current densities, J c , measured in magnetic fields of 0, 5, and 8 T are about 4.2 × 10 5 , 3.6 × 10 4 , and 1.4 × 10 4 A cm −2 , respectively. At 20 K and 0 T, the magnetic J c is about 2.4 × 10 5 A cm −2. These results show that at zero and low fields, the values of the magnetic J c for Ti-sheathed MgB 2 wires are comparable with the best results available for the Fe-sheathed MgB 2 wires. At high fields, however, the J c for Ti-sheathed MgB 2 wires appears higher than that for the Fe-sheathed MgB 2 wires.

Properties of stabilized MgB2composite wire with Ti barrier

“…Recently, titanium as a sheath material has been used for single-core MgB 2 wires by Serquis and Alessandrini et al [9,10]. They did not observe any reaction or diffusion up to 900 • C and the manufacturing process for titanium grade 2 was similar to that used for iron sheathed wires [10,11].…”

Negative effects of crystalline-SiC doping on the critical current density in Ti-sheathed MgB2(SiC)ysuperconducting wires

“…Recently we have successfully fabricated Ti-sheathed, undoped MgB 2 wires with high J c and demonstrated that the performance of a Ti-sheath on J c is comparable to or even better than an Fe-sheath [15]. To further increase J c for future applications of Ti-sheathed MgB 2 wires in lightweight superconducting magnets, we fabricated Ti-sheathed MgB 2 wires doped with crystalline nano-SiC (20 nm) at different doping levels.…”

The Combined Influence of SiC and Rare‐Earth Oxides Doping on Superconducting Properties of MgB 2 Wires

“…We also reported the effect on Ti-sheathed MgB 2 wires dual doped with nanosized rare-earth oxides and SiC. Our selection of titanium as sheath material was based on the following facts: (1) the performance of Ti-sheathed wires is comparable to or even better than iron-sheathed wires [21]; (2) the magnetic measurement is much easier on Ti-sheathed wire than ferromagnetic metal sheathed wire.…”