The use of the Bi-2223 superconducting tubes

• Published in: IEEE transactions on applied superconductivity Vol. 7; no. 2; pp. 703 - 706
• Main Authors: Plechacek, V., Hejtmanek, J., Sima, V.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01-06-1997; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Electric connection. Cables. Wiring; Electrical engineering. Electrical power engineering; Exact sciences and technology; Fault current limiters; Heat treatment; Magnetic flux; Magnetic materials; Permanent magnets; Pressing; Shape; Superconducting films; Superconducting magnets; Superconducting materials; Various equipment and components
• DOI: 10.1109/77.614601
• EISSN: 1558-2515
• ISSN: 1051-8223

The work is mainly devoted to the possibility of the use of the BPSCCO tubes as permanent superconducting magnets, i.e. to the increase of the critical current density J/sub c/ and the trapped magnetic flux density B/sub tr/. The obtained results are also applied for the superconducting current leads and fault current limiters. The Bi-2223 tubes were prepared by the isostatic pressing using a pressing mandrel and they were thermomechanically processed several times. It was shown that the texture formed during the process and favorably influencing J/sub c/ is more pronounced in tubes with thinner walls. With regard to this fact, a superconducting magnet composed of many thinner tubes was prepared. The trapped magnetic flux density in the hole of the magnet reached up to 0.5 T at 20 K and, after cooling the magnet at 15 K, the B/sub tr/ value of 0.5 T was maintained seemingly without relaxation for five days. This multi tubes magnet was also compared with one composed of two tubes of thicker walls. The J/sub c/ of about 1000 A/cm/sup 2/ (at 77 K and under self field of about 20 mT) achieved for the single tubes indicates an advantage of the use of relatively thin Bi-2223 tubes for the superconducting current leads and fault current limiters.