SiC addition for MgB/sub 2/ superconducting wire by suspension spinning

Abstract

The effect of nanoscale SiC addition on the field dependence of J c for MgB 2 superconducting wire by suspension spinning was examined to enhance the flux pinning. The suspension spinning of commercially available MgB 2 and SiC powders was examined to fabricate a long superconducting MgB 2 wire by using the spinning medium of poly(vinyl alcohol) (PVA) or polyacrylonitrile (PAN). The as-drawn filaments were uniaxially pressed under 20 MPa at 200 C for 8 h to remove volatile components and connect the MgB 2 grains. The filamentary samples were enveloped by an iron sheet with a pellet of mixed powder of Mg and B to prevent Mg loss, and vacuum-sealed in a fused quartz tube and sintered. The field dependence of J c for the samples was examined at 4.2 K in magnetic fields up to 14 T. The J c of the sample was strongly dependent on the spinning medium and sintering condition. Addition of 5 at% SiC in the sample spun by PVA medium attained the maximum J c value more than 1000 A cm 2 at 4.2 K by applying the field of 14 T.