High-Tc Bi-Pb-Sr-Ca-Cu-O Superconductor Prepared by Plasticized Extrusion

By using plasticized superconducting raw compounds, we extruded string-shaped and tape-shaped wires. Adopted Bismuth-lead-strontium-calcium-copper oxides (Bi-Pb-Sr-Ca-Cu-O) have been produced by solid-state reactions. They were calcined at 850°C for 50 hours, ground, re-calcined and re-ground. The composition of Superconducting pawders were Bi0.7Pb0.3SrCaCu1.5Oy.Plasticized superconducting raw compounds consist of the binders(PVB), the plasticizers(DOP), the dispersants and ceramic powders. Raw compounds were ex-truded to the 1.5mm∅ strings and the 0.5×3.0 or 5.0(thickness×width, mm) tapes.These strings and tapes were sintered, and the superconducting properties(Tc, Jc, SEM, XRD) were measured.The sintering conditions were at 830-850°C, for 50-200 hours. Tc's were not so differed by sintering temperatures and times.The sintered tape-shaped specimens seemed to have the c-axis orientations with the observation of XRD-patterns and SEM-fractured surface.Jc's of tape-shaped wires were superior than string-shaped wires. These values were 60-85, 163-174A/cm2 at 77K OT respectively.The Jc of the wire added about 0.3 wt.mole silver to 1.0 wt.mole BSCCO was 268A/cm2.