Copper sheath MgB2 wires fabricated by an in situ PIT method

✍ Scribed by S. Shimura; T. Machi; M. Murakami; N. Koshizuka; K. Mochizuki; I. Ishikawa; N. Shibata

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 371 KB
• Volume: 412-414
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2004.02.222

✦ Synopsis

We investigated the applicability of Cu as sheath materials for MgB 2 wires prepared by in situ PIT (powder-in-tube) method in comparison with stainless steal. Since the critical current density of MgB 2 increases with TiH 2 doping, we prepared TiH 2 doped MgB 2 Cu sheath wires 40 m in length and £ 1.0 mm or 0.5 • 1.0 mm 2 in cross section by rotary swaging, drawing, and two-axial rolling under cold working. We then annealed the samples at 600-850 °C for 1-2 h in Ar gas atmosphere. The critical current of TiH 2 (6%) doped MgB 2 /Cu short sample annealed at 650 °C reached 208 A (J c ¼ 230 kA/cm 2 ) at 4.2 K and self-field. We also fabricated several coils using these wires. The I c value was 100 A at 4.2 K for a coil prepared with use of a 5 m length wire. These results suggest that it is possible to fabricate Cu sheathed MgB 2 wires with good performance by using the in situ PIT method.