Superconducting Wires Obtained by Bi-2223 Coating, or Bi-2223 Synthetization from Precursors, on a Metal Core
Abstract
Superconducting wires have been prepared by Bi1.6Pb0.4Sr2Ca2Cu3O10 (Bi-2223) coating of a great number of different metallic cores. The best electrical results (high Tc0 and small Tc) were obtained with silver and silver coated iron cores for a sintering temperature Ts = 835 °C. For short sintering durations (less than 32 h) the resistance-versus-temperature curves R = f(T) presented several drops revealing the existence of several phases. In most cases one of these phases at least presents a large T_c value that can be estimated by a percolation based parametrization method. For very long sintering durations, up to six days, and with addition of an excess of PbO (the percentage of PbO in excess is related to the sintering duration), these curves presented only one drop. In the latter case Tc0 = 108 K, corresponding to 60% Bi-2223, as shown by the percolation based parametrization method. It has been shown also that it is not necessary to use a good Bi-2223 ceramic to obtain these results, even precursors can be used, the Bi-2223 coating being then synthesized on the silver core. The role of the substrate, sintering temperature and of the excess of PbO will be discussed.
- Publication:
-
Physica Status Solidi Applied Research
- Pub Date:
- June 1997
- DOI:
- 10.1002/1521-396X(199706)161:2<429::AID-PSSA429>3.0.CO;2-H
- Bibcode:
- 1997PSSAR.161..429L