Zone melting-refining in Bi-Pb-Sr-Ca-Cu-O superconductor prepared through the sol-gel method

Abstract

A zone melting-refining technique, with a horizontal sample-holding pattern for incorporating grain orientation in sintered bismuth-based superconductor (BPSCCO) is presented. Acrylate precursor-derived BPSCCO powder was uniaxially compacted into strips of 60 mm×10 mm ×2mm and sintered at 845°C for 20 h to obtain 90% density. These strips were zone melted in a three-zone furnace which had an independent temperature control system for each zone. The grain orientation in the sample was studied by scanning electron microscopy and X-ray diffraction. In the case of a BPSCCO-Ag (5%) composite, the silver was seen to flow along the intergrannular boundaries of the BPSCCO grains. The present technique is an easy and fast method to introduce orientation of grains with large aspect ratio into sintered BPSCCO or Ag-BPSCCO composite under partial melting-refining conditions. The possibility of extending the present technique to silver-sheathed wire and tapes is also indicated.