Very fast formation of superconducting MgB2/Fe wires with high Jc
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 min above 800°C are as good as those sintered for longer times. In fact, the Jc field performance for the most rapidly sintered sample is slightly bette r than for all other samples. Jc of 4.5×105 A/cm2 in zero field and above 105 A/cm2 in 2 T 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.
X. L. Wang, S. Soltanian, J. Horvat, A. H. Liu, M. J. Qin, H. K. Liu, and S. X. Dou. "Very fast formation of superconducting MgB2/Fe wires with high Jc" Physica C: Superconductivity and its Applications 361.3 (2001): 149-155.
Available at: http://works.bepress.com/ssoltanian/20