Optimization of the Bi(Pb)-2223 bulk technology

• Published in: Physica. C, Superconductivity Superconductivity, 1997-08, Vol.282-287, p.2585-2586
• Main Authors: Pollert, E., Plechácˇek, V., Hejtmánek, J., Hudáková, N., Chval, J., Jirák, Z., Knízˇek, K., Sˇíma, V.
• Format: Article
• Language: English
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/S0921-4534(97)01429-9

Bulk Bi(Pb)-2223 ceramics affords a possibility for various applications like current leads, fault current limiters, magnetic shields and magnets. Evidently their practical use depends on the properties gained by the applied processing i.e. on a number of the technological parameters. In spite of their complex character several steps were distinguished and investigated. The optimum starting composition was found to be x∼0.3, and the optimum sintering temperature for x = 0.26 at ∼835° C (Bi2.1−xPbxSr2Ca2Cu3O10+δ). The intermediate cold pressing enhances significantly the exaggerated growth of highly oriented Bi-2223 grains. With respect to the required grains orientation either uniaxial or isostatic pressing should be applied. The investigation of the texture “gradient” across the walls of the superconducting tubes resulted to, their optimized thickness of ∼2 mm. On the basis of the study the superconducting magnet with the trapped magnetic flux density of 0.5 T at 20 K inside the magnet hole was constructed.