Relationship among synthesis, microstructure and properties in sinter-forged Bi-2212 ceramics

High quality Bi-2212 powders ware prepared using three different synthetic methods (solid stare, sol-gel and polymer matrix), showing that the polymer matrix method is very promising from the point of view of the synthesis ti me and grain size. The Bi-2212 sintered pellets were then submitted to sint er-forging process to obtain textured ceramic discs. The discs were charact erized by XRD, pole figures and SEM to determine the phase purity, the text ure degree and the microstructure, respectively. Following characterization , the discs were cut into bars and annealed for 12 h at different temperatu res ranging between 845 and 873 degrees C to determine the best thermal tre atment, whereafter they were characterized using resistivity and transport J(c) measurements. It has been found that most of the bars had a T-c around 92 K and that transport properties can be correlated to the samples' micro structure. (C) 1999 Elsevier Science B.V. All rights reserved.