• Shahbazi, Mahboobeh
• Hossain, Shahriar
• Ravishankar, Ramkumar
• Manshadi, Ali Dehghan

Abstract

<p>An intrinsic powder-in-tube technique is used to fabricate Cu-sheathed MgB2 with and without a Ti barrier. The effect of heat treatment on reaction layers between the Cu sheath, Ti barrier, magnesium and boron is evaluated by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray powder diffraction. Annealing the Cu (sheath)/Ti (barrier) prior to in situ heat treatment of the Mg + 2B reaction improves formation of a pure MgB2 core and eliminates subsequent reactions between B powder and the Ti barrier. Microstructural study of the interface between pure MgB2 and annealed Ti/Cu sheath does not show any evidence of reaction and diffusion between B and Ti which is beneficial for superconducting properties. Magnetization measurements of MgB2 superconducting wires have shown that the critical current density, Jc, of a Cu-sheathed wire combined with a Ti barrier can significantly enhance performance compared with a Cu-sheathed MgB2 wire without a Ti barrier. This enhancement is due to elimination of a MgCu2 interface layer between the copper sheath and magnesium powder for wires when a Ti barrier is involved. Pre-annealing of the Cu (sheath)/Ti (barrier) does not affect the Jc of MgB2 wires. This could make a positive effect on the Jc of the wires with finer filaments. </p>

Topics

• density
• impedance spectroscopy
• microstructure
• scanning electron microscopy
• Magnesium
• Magnesium
• copper
• Boron
• annealing
• current density
• wire
• magnetization
• X-ray spectroscopy