Development of a Scalable Tl-1223 Tape Process — Thallination of Powder Precursor Coatings
Superconducting tapes, 10–20 cm long, of TlBa2Ca2Cu3O9 on Ag have been fabricated by deposition of a thallium-free powder precursor on Ag followed by reaction with a thallium oxide vapor species. Single-sided and two-sided coatings are prepared using a spray-deposition or dip-coating, respectively. The coated tapes are annealed and then mechanically processed to density the precursor. Continuous thallination of precursor tapes is performed by pulling the coated tape through a two-zone furnace at constant velocity and gave similar results as batch processing. Critical currents of the order 10–20 A at 77K, zero field for a 5 mm wide tape are observed. Properties as a function of magnetic field indicate reduced flux creep compared to the more anisotropic bismuth cuprate superconductors and make thallium 1223 an attractive material for conductor applications at high temperatures.
KeywordsCritical Current Critical Current Density Spray Pyrolysis Precursor Powder Silver Foil
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