Fabrication and properties of Nb3Sn tapes by the "Bronze process" application to superconducting power transmission lines

Long lengths of Nb
3
Sn tapes have been prepared by extrusion and rolling of bronze clad niobium billets. Fine grained layers up to 5 μm thick, were formed by heat treating at 750°C for several hours. By combining the "bronze-process" with an external Sn diffusion technique layers up to 15 μm thick were produced. Loss data at 60 Hz are given for various configurations with and without copper stabilizing layers. DC critical current densities are also given.