Large field generation with a hot isostatically pressed powder-in-tube MgB₂coil at 25 K

Abstract

Abstract. We present the fabrication and test results of Hot-Isostatic-Pressed (HIPed) Powder-in-Tube (PIT) MgB 2 coils. The coils properties were measured by transport and magnetization at different applied fields (H) and temperatures (T ). The engineering critical current (J e ) value is the largest reported in PIT MgB 2 wires or tapes. At 25 K our champion 6-layer coil was able to generate a field of 1 T at selffield (I c > 220 A, J e ∼ 2.8 × 10 4 A/cm 2 ). At 4 K this coil generated 1.6 T under an applied field of 1.25 T (I c ∼ 350 A, J e ∼ 4.5 × 10 4 A/cm 2 ). These magnetic fields are high enough for a superconducting transformer or magnet applications such as MRI. A SiC doped MgB 2 single layer coil shows a promising improvement at high fields and exhibits J c > 10 4 A/cm 2 at 7 T.

The effect of doping level and sintering temperature on Jc(H) performance in nano-SiC doped and pure MgB2 wires

“…The exceptional properties of SiC as a dopant have been verified by a number of groups over the past few years. [7][8][9][10][11][12][13][14][15][16][17][18] However SiC doping was found to have some negative effect on J c in the low field region. The J c for SiC doped MgB 2 was lower than that for undoped MgB 2 below 4 T at 5 K and below 2.5 T at 20 K. 2,13,17 There are many applications in the low field region such as in open magnetic resonance imaging ͑MRI͒ transformers and electric cables which normally operate at around 1-3 T. Thus it is important that the enhancement of J c by SiC doping can be extended to include all the field regions.…”

Superconducting characteristics of MgB2 wires obtained by Reactive Liquid Mg Infiltration

“…Our aim is to compare the values of SC critical current density of the present wires with those of the old ones produced by the same RLI process [11]. These figures are in the higher levels of the range of similar manufacts published by the major players in this field [1,2,4,5]. Nevertheless the actual wires have a substantially better disposition of the SC material, which induces a big improvement in the engineering critical current density.…”

“…The main processing technologies for the MgB 2 wires and tapes are a variance of the Powders in Tube (PIT) and are performed either via "in situ" or "ex situ" mode [1][2][3][4][5][6][7][8]. increase the thermal stabilization of the wire and improve the transport properties in magnetic fields.…”

Influence of Mg particle size on the reactivity and superconducting properties of in situ MgB2

“…Fabrication of long length MgB 2 conductors is relatively easy and the raw materials Mg, B and the sheath materials are inexpensive as compared to other practical superconductors [2,3]. MgB 2 superconducting magnets and coils, producing 1-2 T field are tested successfully in many laboratories [2][3][4][5][6]. For technological applications long conductors with high irreversibility field (H irr ), upper critical field (H C2 ) and infield critical current density (J C (H)) are required.…”