Extrusion of superconducting wires of YBa2Cu3O7−x

Abstract

High T_c superconductors need to be fabricated into desirable configurations such as wires for practical applications. Toward this objective, the plastic extrusion process was applied to the fabrication of wires and rods of YBa₂Cu₃O_7−x. The ceramic oxide powder is combined with several organic additives to form a slurry which is extruded by forcing it through a small aperture. This is subjected to a sequence of heat treatments for drying, binder burn-out, and sintering. The critical current density of these wires ranges from 800 A/cm² to 1500 A/cm² depending upon the diameter and the current-carrying capacity is uniform over long lengths of up to 140 cm. This process was also applied to fabrication of larger cross-sectional area rods and hollow cylinders, capable of carrying up to 245 A. The mechanical properties of these wires were also investigated.