FABRICATION AND CHARACTERIZATION OF HIGHLY TEXTURED (BI,PB)(2)SR2CA2CU3OX SUPERCONDUCTING CERAMICS USING HIGH MAGNETIC-FIELD AND COLD ISOSTATIC PRESSING

High textured (Bi, Pb)(2)Sr2Ca2Cu3Ox ceramics have been fabricated by aligning deflocculated flakes of (Bi, Pb)(2)Sr2Ca2Cu3Ox suspended in a n organic medium by means of a high de magnetic field (6 T) at room te mperature followed by cold isostatic pressing. The proportion of the ( Bi, Pb)(2)Sr2Ca2Cu3Ox phase in the precursor powder was carefully cont rolled, and the characteristics of the powder, such as size distributi on and morphology, were determined. A high degree of grain alignment w as found in the specimens after the magnetic alignment, although the b ulk density of the materials was low. Cold isostatic pressing substant ially increased the density of the magnetically prealigned specimens w hich also resulted in a slight decrease in the degree of grain alignme nt. This minor realignment was found to be due to the various kinds of processing defects that appeared in the specimens during compaction d ue to the grinding and cracking of the grains and their interlocking. The microstructural and superconducting properties of the sintered cer amic have been studied using texture goniometry, high resolution scann ing electron microscopy, transmission electron microscopy, ac magnetic susceptometry, and critical current measurements.