Fabrication of Bi-2223 Superconducting Joint by Hot-Pressing Process

Superconducting joints between Bi-2223 tapes were fabricated by a hot-pressing process with a 24 h heat treatment. We developed specialized equipment to apply pressure to the joint during the heat treatment. Hot pressing is effective for producing practical critical current even by the short heat treatment. The superconducting joint in a closed-loop showed a resistance of 7.3 × 10−15Ω at 4.2 K in self-field. The maximum persistent current that could flow in the loop was estimated to be about 170 A at 4.2 K. The purification and further densification of the intermediate layer in the superconducting joint are issues that need to be addressed. Once these issues are addressed, the hot-pressing process should be a promising method for fabricating high-performance Bi-2223 superconducting joints in high yields within a short processing time.