Development of high performance Ag sheathed Bi2223 wire

• Published in: Physica. C, Superconductivity Superconductivity, 2004-10, Vol.412, p.1066-1072
• Main Authors: Kato, T., Kobayashi, S., Yamazaki, K., Ohkura, K., Ueyama, M., Ayai, N., Fujikami, J., Ueno, E., Kikuchi, M., Hayashi, K., Sato, K.
• Format: Article
• Language: English
• Subjects: Bi2223 phase homogeneity; Bi2223 wire; Connectivity; Pressure sintering; Relative mass density
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2004.05.006

A silver sheathed Bi2223 wire is widely used to build various prototype models taking advantage of longer length wires with a relatively high critical current. The Bi2223 wire is expected to early realize full-scale practical use in the area of cables, magnets and so on. However, further improvements in some aspects of performance are required to realize commercial products. In view of critical current ( I c), I c at around 77 K in lower magnetic fields and at a lower temperature in higher magnetic fields are important for a cable system and a magnet system, respectively. The improvements in phase homogeneity, grain alignment and good connectivity between grains are mainly necessary for I c at a higher temperature. For I c at a lower temperature, the improvement in the property of grain boundary is considered to be effective due to the decrease of the coherent length. In order to drastically change the above factors, we have been studying a new sintering process under a pressurized atmosphere. This new process has a significant effect on the increase of the critical current, and further on the enhancements of mechanical properties and reliability in thermal cycles.