Superconducting Properties and Structure of In-Situ MgB$_{2}$ Tapes With SiC and TiC Addition Prepared by Hot Pressing

Abstract

In-situ powder-in-tube MgB2 tapes have been prepared through a hot pressing process. Magnesium hydride MgH2 and amorphous B powders were mixed to synthesize MgB2 superconductor. The mixed powder was encased in a steel tube and rolled into a monocore tape of about 4 mm in width and 0.5 mm in thickness. Nano-sized SiC and TiC powders were added to the MgB2 core. The tapes were hot-pressed under 100 MPa during the heat treatment in Ar gas atmosphere. The Ic for the hot-pressed tapes with 5 mass% SiC addition exceeds 300 A at 4.2 K and 5 T, which corresponds to a core Jc of nearly 1,000 A/mm2. The core Jc is enhanced by more than a factor of two compared to that of tapes without pressing during the heat treatment. The higher Jc in hot pressed tapes results from the improvement of the denser MgB2 structures with less voids and better linkage among MgB2 grains.