Structure and critical current of Ni-sheathed PIT MgB2 tapes with In metal powder addition

PIT MgB2 tapes have been prepared through an ex situ process using a Ni sheath. Different kinds of metal powder were added to the MgB2 core. Soft metals like Ag and Cu show an elongated morphology in the core after the fabrication. Low melting point metal powder like In impregnates into gaps among MgB2 grains due to the heat generated during the fabrication. The addition of In and Sn produces an appreciable increase in the Jc of MgB2 tapes. The annealing at 200 deg. C yields further increase in the tape with In and Sn addition. The enhancement of Jc by the In addition and the 200 deg. C annealing reaches a factor of ∼7. The In addition also improves the n value and the strain tolerance of the tape. The improvement in the linkage of MgB2 grains seems to be the major origin for the enhancement in Jc by the In addition