THE FABRICATION AND THERMOMECHANICAL PROCESSING OF AG-BI-2223 JELLY-ROLL WIRES

For this feasibility study, silver/superconductor jelly-roll samples w ith a superconductor composition of Bi1.8Pb0.4Sr2Ca2Cu3Ox (2223), were fabricated via a thick-film processing technique. It was found that t he densification and alignment of 2223 grains along the Ag layers was crucial to achieving high critical current densities (J(c)). The effec ts of cyclic mechanical working and heat treatment were investigated t o develop a scheme to maximize J(c). The highest zero-field J(c) value of 2650 A CM-2 (I(c) = 43 A) was obtained in a jelly roll heat treate d at 815-degrees-C, where the majority of the mechanical deformation w as performed prior to the first heat treatment. Magnetic-field-depende nce measurements made in a 50 G field showed a 23% reduction in J(c) w hen the field was applied parallel to the current flow, and a 30% redu ction when the field was applied perpendicular to the current flow. Th is was superior to the best comparable powder-in-tube samples.