Preparation and Characterization of Tl-2223 Superconductor Coating Using the Electrophoretic Deposition Method

Abstract

Tl2Ba1.6Sr0.4Ca2Cu3O10+y(Tl-2223) superconductor coatings on Ag substrates were prepared using the electrophoretic deposition method. The Tl-2223 single phase was obtained by applying a high Tl composition of superconducting powder at the proper sintering conditions in order to prevent evaporation of Tl during the sintering process. Nominal Tl compositions of the superconducting powders were 2.00-2.50, which were stoichiometric and excess compositions. Electrophoretically deposited coatings using these superconducting powders were buried in the superconducting powder and sintered at 815°C for 6h in air. For the case of the nominal Ti compositions of 2.20-2.30, superconducting powders were used for the electrophoretic deposition, the Tl compositions of sintered superconductors were 1.80-1.87, the critical temperature (Tc, zero) was 110-112K, and these samples were almost single phase. On the other hand, Ag2O powder was electrophoretically deposited onto the Tl-2223 electrophoretic deposition coating. After heat treatment at 315°C for 2h, the Tl-2223 pre-sintered superconductor coating was coated with silver. It was then sintered at 815°C for 6h. Although they were not buried during the sintering process, the Tl compositions of the obtained samples were 1.81-1.83 with a Tc, zero of 111-113K. This silver coat acts to restrain Tl evaporation and protects the coating of the superconducting layer. Moreover, the critical current density (Jc) of silver coated superconductor coating was 67A/cm2 (77K, 0T) when a nominal Tl composition of 2.30 superconducting powder was used for the electrophoretic deposition.