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

摘要

20 meters long length of in-situ SiC doped ${rm MgB}_{2}/{rm Fe}$, ${rm MgB}_{2}/{rm Nb/Cu/Stainless} {rm Steel}$ (SS) mono- or ${rm MgB}_{2}/{rm Nb/Cu/Fe}$ multi- filamentary wires with high critical current densities have been prepared by combining both powder in tube (PIT) and continuous tube forming u00026; 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 ${rm MgB}_{2}$ wires were investigated by the analysis of XRD, SEM and the $J_{rm c}$ measurements. The optimized sintering process was found to be 830$^{circ}{rm C}$ for 15 minutes. It was shown that the magnetic $J_{rm c}$ value of ${rm MgB}_{2}/{rm Nb/Cu/SS}$ wire reaches $6times 10^{5} {rm A/cm}^{2}$ (10 K, 0 T), while the transport $J_{rm c}$ value in this 8 at.% SiC doped ${rm MgB}_{2}/{rm Fe}$ mono- filamentary wire is more than $10^{4} {rm A/cm}^{2}$ at 4.2 K and a field of 11 T. The estimated $J_{rm c}$ value approaches $10^{6} {rm A/cm}^{2}$ at 4.2 K and zero field. Further enhancement of $J_{rm c}$ in both mono- and multi- wires is expected for improving the filling density of the CTFF $+$ PIT processing.