High Critical Current Densities in SiC Doped In-Situ${\hbox{MgB}}_{2}$ Wires Prepared by Continuous Tube Forming and Filling Technique

Abstract

20 meters long length of in-situ SiC doped MgB2/Fe, MgB2/Nb/Cu/stainless steel (SS) mono- or MgB2/Nb/Cu/Fe multi- filamentary wires with high critical current densities have been prepared by combining both powder in tube (PIT) and continuous tube forming & filling (CTFF) processes. Particular efforts were made in view of the optimization of the manufacturing and annealing processes of the wires. The as obtained mono- wires were sintered under a vacuum furnace and the effects of the sintering temperature on the properties of the MgB2 wires were investigated by the analysis of XRD, SEM and the Jc measurements. The optimized sintering process was found to be 830degC for 15 minutes. It was shown that the magnetic Jc value of MgB2/Nb/Cu/SS wire reaches 6times105 A/cm2 (10 K, 0 T), while the transport Jc value in this 8 at.% SiC doped MgB2/Fe mono- filamentary wire is more than 104 A/cm2 at 4.2 K and a field of 11 T. The estimated Jc value approaches 106 A/cm2 at 4.2 K and zero field. Further enhancement of Jc in both mono- and multi- wires is expected for improving the filling density of the CTFF + PIT processing.