Co-reaction of textured superconducting, conducting and insulating multilayer composites

Many applications of superconductors are limited by low values of the engineering critical current density (J/sub cc/). Significant improvements are possible through the merger of green tape and composite reaction texturing technologies. Tape casting and elastomer processing techniques have produced insulating (MgO and Al/sub 2/O/sub 3/), conducting (Ag) and superconducting (Bi-2212+MgO-fibre) tapes with uniform thickness ranging from 0.1-2 mm. Green tapes of the desired thickness can be laminated into multilayer structures and co-reacted; the superconducting layer occupying over 50% of the cross section allows the engineering of an artefact for optimal I/sub c/, and maximum J/sub c/c. The texture observed in the Bi-2212 layer is induced by specifically aligned MgO-fibres. As a necessary step in developing this technology, results are presented on (1) additions of 0-10 %wt Ag to Bi-2212 in order to modify its partial melt behaviour, (2) control of the shrinkage and densification of individual layers which is critical to uniformity and (3) chemical buffering of the Bi-2212 layer from insulating layers of doped MgO and Al/sub 2/O/sub 3/ during co-reaction.