Enhancement of the critical current density of in-situ powder-in-tube processed MgB2 wires with both xylene and SiC addition

Abstract

The addition of a liquid hydrocarbon, xylene, to the starting powder of in-situ powder-in-tube (PIT) processed MgB2 wires was determined to be effective in enhancing the critical current density (Jc) in both high and low magnetic fields. Unlike the addition of SiC nanopowder, which introduces carbon substitution for boron, xylene addition reduced the amount of boron that remained unreacted after the heat treatment and the MgB2 grain size, which resulted in an almost fully-reacted MgB2 core and more flux pinning centers. The addition of both xylene and SiC powder to the starting powder provided a higher Jc than either separate addition to the wire process because both mechanisms associated with xylene and SiC additions work together. For heat treatment at 650 °C, Jc for the xylene added wire achieved 2.2 × 103 A/cm2 at 10 T, which was triple that of the pure sample. The co-added wire had a Jc of 6.3 × 103 A/cm2 at 10 T, which was higher than the SiC added wire, of which Jc was 4.1 × 103 A/cm2 at 10T.