AC loss and DC critical current densities of Nb3Sn tapes by the solid state diffusion process

The effects of metallurgical processing on 60 Hz ac losses and dc critical currents in Nb3Sn tapes fabricated by the solid state diffusion technique were investigated. An addition of Al to the Cu-Sn alloy for the matrix resulted in large reduction in the ac losses of Nb3Sn tapes, but the highest linear critical current densities were observed in Nb3Sn tapes produced with a Nb-1 wt% Zr core in a Cu-13 wt% Sn matrix. Values of the losses and the critical currents in these tapes can meet the present requirements for the ac superconducting power cables.