Field dependence of the critical current density of MgB₂/Cu wire for coil development

Abstract

The critical current density (J c ) of monofilament Cu/MgB 2 wire was measured between 4.2 and 30 K with a variable temperature insert (VTI) in a 20 T superconducting magnet using the DC pulse four-wire method with a 1 μV cm −1 criterion. The critical current density, J c , was measured to be 0.83 × 10 4 A cm −2 at 3 T at 21 K and 0.66 × 10 4 A cm −2 at 8 T at 4.2 K for the MgB 2 sample, which was annealed at 700 • C for 30 min with 5.8 • C min −1 heating rate under 4% H 2 -Ar gas flow. Scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS) and x-ray diffraction (XRD) analysis were used to characterize the microstructure of the samples.

Magnezyum Di̇borür Telleri̇n Mi̇kro Yapisi Ve Geri̇lme Anali̇zi̇ - Microstructure and Stress Analysis of the Magnesium Diboride Wires

“…Magnezyum Diborür telleri, transformatör, jeneratör, solenoid, manyetik rezonans görüntüleme (MRI) ve yarış pisti bobinleri gibi uzun ömürlü uygulamalar için birçok gruptan tüp içinde toz prosesi ile üretilmiştir [1][2][3][4][5]. 2003 yılından bu yana Magnezyum Diborür bobinlerini geliştirmek için pek çok çalışma gerçekleşmiştir [6].…”

Stress analysis of ceramic insulation coating on Cu/MgB2 wires for W&R MgB2 coils

“…In the last few years, many groups fabricated MgB 2 wires using powder in-tube process for long length applications such as transformer, generator, solenoids, the Magnetic Resonance Imaging (MRI) and racetrack coils [1][2][3]. Numerous efforts to develop MgB 2 coils are ongoing.…”

The electric field jump—detection of damaged Nb barrier in MgB2wires annealed under pressure

“…This damaged area (green circle) is five times greater than the area of damage in wire with monel sheath and three times larger than the area of damage in wire with glidcop sheath.Construction of the wires indicates that damaged area could lead to creation of phases of CuMg 2 and Cu 2 Mg (on the outside of the filament). These phases are formed in MgB 2 wires in copper sheath without Nb barriers[24,25]. A smaller amount of Mg in the filament might result in creation of higher borides, e.g.…”