PROCESSING AND CHARACTERIZATION OF AG-CLAD BI-2223 SUPERCONDUCTORS

Practical applications of high-temperature superconductors will be gov erned by their current transport and mechanical characteristics. With careful control of the processing parameters high-quality long-length mono- and multifilament Bi-2223 conductors have been fabricated by the powder-in-tube technique. A critical current density (J(c)) of up to 1.2 x 10(4) A cm(-2) has been observed at 77 K in a 1260-m-long multif ilament conductor containing 37 monocore filaments. A high-temperature superconducting magnet and a prototype transformer were fabricated an d characterized from such long-length conductors. Extensive studies on the in-situ strain characteristics of the mono- and multifilament con ductors have been conducted. Multilayer silver/superconductor composit e tapes, fabricated by a novel chemical etching technique, were also o bserved to exhibit improved strain tolerance characteristics. To furth er improve the current characteristics of the Bi-2223 tapes the wire-i n-tube technique was adopted. A J(c) value > 10(5) A cm(-2) at 77 K an d in self field have been obtained in a Bi-2223 tape fabricated by the wire-in-tube method.