Very fast formation of superconducting MgB2/Fe wires with high Jc

Abstract

In this paper we have investigated the effects of sintering time and temperature on the formation and critical current densities of Fe-clad MgB2 wires. MgB2 wires were fabricated using the powder-in-tube process and sintered for different periods of time at predetermined temperatures. All the samples were examined using XRD, SEM and magnetisation measurements. In contrast to the common practice of sintering for several hours, the present results show that there is no need for prolonged heat treatment in the fabrication of Fe-clad MgB2 wires. A total time in the furnace of several minutes is more than enough to form nearly pure MgB2 with high performance characteristics. The results from Tc, Jc and Hirr show convincingly that the samples which were sintered for 3 minutes above 800 oC are as good as those sintered for longer times. In fact, the Jc field performance for the most rapidly sintered sample is slightly better than for all other samples. Jc of 4.5 times 10 ^5 A/cm2 in zero field and above 10 ^5 A/cm2 in 2T at 15 K has been achieved for the best Fe-clad MgB2 wires. As a result of such a short sintering there is no need for using high purity argon protection and it is possible to carry out the heat treatment in a much less protective atmosphere or in air. These findings substantially simplify the fabrication process, making it possible to have a continuous process for fabrication and reducing the costs for large-scale production of MgB2 wires.

15 pages, one table, 9 figures, submitted to Physica C on June 8, 2001

References in corpus (2)

• Superconductivity in Dense $Mg{B}_2$ Wires
• Flux Jumping and a Bulk-to-Granular Transition in the Magnetization of a Compacted and Sintered MgB2 Superconductor

Cited by in corpus (19)

• Effect of carbon nanotube doping on critical current density of MgB2 superconductor
• High performance new MgB2 superconducting hollow wires
• Effect of nano-carbon particle doping on the flux pinning properties of MgB2 superconductor
• Superconductivity, critical current density, and flux pinning in MgB_{2-x}(SiC)_{x/2} superconductor after SiC nanoparticle doping
• Improvement of critical current in MgB2/Fe wires by a ferromagnetic sheath
• Properties of superconducting MgB_2 wires: "in-situ" versus "ex-situ" reaction technique
• Microstructure and high critical current of powder in tube MgB2
• Significant enhancement of flux pinning in MgB2 superconductor through nano-Si addition
• Transport critical current of Solenoidal MgB2/Cu Coils Fabricated Using a Wind-Reaction In-situ Technique
• Study of Ag and Cu / MgB2 powder-in-tube composite wires fabricated by in-situ reaction at low temperature
• The effect of sample size on field dependence of Jc for MgB2 superconductor
• Superconducting screening on different length scales in high-quality bulk MgB2 superconductor
• Improvement of critical current density in the Cu/MgB2 and Ag/MgB2 superconducting wires using the fast formation method
• Transport Properties and Exponential n-values of Fe/MgB2 Tapes With Various MgB2 Particle Sizes
• Interaction between superconductor and ferromagnetic domains in iron sheath: peak effect in MgB2/Fe wires
• Magnetic shielding in MgB2/Fe superconducting wires
• Dendritic flux avalanches in a superconducting MgB2 tape
• Single-filament Composite MgB2/SUS Ribbons by Powder-In-Tube Process
• Supercurrents in Magnesium Diboride/Metal Composite Wire