27 August 2017 to 1 September 2017
RAI Congress Center, Amsterdam, The Netherlands
Europe/Amsterdam timezone

Present status of Bi-2212 conductor technology

31 Aug 2017, 10:00
15m
Emerald Room

Emerald Room

Regular 15 minutes Oral Presentation F2 - High-Tc Wires and Cables Thu-Mo-Or30

Speaker

David Larbalestier (National High Magnetic Field Laboratory)

Description

A critical stage for any conductor technology, especially a wind and react (W&R) technology like Bi-2212 or Nb3Sn occurs when manufacturing becomes sufficiently mature for magnet use. This is now the case for Bi-2212, the only round wire, twisted, multifilamentary HTS conductor. Bi-2212 had fallen out of favor a decade ago because of its inferior Jc and complex heat treatment for W&R use. In the last 5-7 years, with support from the US DOE-HEP Office, all facets of the conductor technology have now been demonstrated. After losing the legacy powder provider 3 years ago, good powder is now being manufactured by two sources (MetaMateria and nGimat) and one wire company (OST) is making very high critical current density wire in single, multi-km piece lengths on the 10 kg scale. Although the highest Jc values are only presently obtained with overpressure heat treatments at ~ 50 bar, such heat treatments also considerably broaden the heat treatment window, making the heat treatment compatible with full-scale coil manufacture. Insulation schemes fully appropriate for magnets have also been demonstrated. The current density properties are very attractive for use in high fields: for example, Jc(16T, 4.2K) now reaches 4000 A/mm2, some 3 times the value possible with Nb3Sn, while Jc(30T) can reach 2900 A/mm2. Hysteretic losses of twisted wires are very comparable to ITER Nb3Sn wires, much less than for REBCO and Bi-2223 tape conductors. While the Ag matrix has low E and generally low yield stress, reinforced, slightly rectangular conductors with high strength properties are being developed by Solid Materials Solutions. At the MagLab we are applying Bi-2212, Bi-2223 and REBCO to high field magnets with fields >20 T. Our view is that there are clear advantages to using Bi-2212 for high homogeneity magnet applications and those requiring flexible conductor architectures.

Submitters Country USA

Primary authors

David Larbalestier (National High Magnetic Field Laboratory) Prof. Eric Hellstrom (National High Field Lab, FSU) Jianyi Jiang (Florida State University) Prof. Fumitake Kametani (NHMFL)

Presentation Materials