Influences of Cu composition and sintering condition in Bi-2223 tapes using Ag-Cu alloy sheath doped with Ti, Zr or Hf

Bi-2223 Ag-Cu alloy sheathed tapes doped with Ti, Zr or Hf were fabricated by a powder-in-tube technique using intermediate uniaxial presses and variations in total sintering times. Increasing Cu compositions in the Ag-Cu alloy sheath doped with certain elements into the sheath, combined with appropriate total sintering times were found to lead good superconducting properties. Furthermore, the best total sintering time varied according to the amount of Cu in the Ag-Cu alloy sheath and the existence of doping elements. A transport critical current density, J(c),, of 4.1 x 10(4) A/cm(2) at 4.2 K, 14 T and 2.2 X 10(4) A/cm(2) at 77 K, 0 T was achieved in Ag-10 at% Cu-0.1 at% Hf sheathed Bi-2223 tapes sintered for total 200 h. (C) 1997 Elsevier Science B.V.