Comparison of the Electrical Properties of Copper Diffusion-Bonded Joints and Solder Joints for \mathrm\text\mathrm Tapes

• Published in: IEEE transactions on applied superconductivity Vol. 35; no. 5; pp. 1 - 5
• Main Authors: Berthet, Gael, Jung, Wonju, Park, Hyunsoo, Hahn, Seungyong, Lee, Sangjin
• Format: Journal Article
• Language: English
• Published: IEEE 01.08.2025
• Subjects: Clamps; Conductivity; Copper; diffusion bonding; Electrical resistance measurement; Ethanol; HTS; joint; REBCO tape; Resistance; Soldering; Surface resistance; Temperature measurement; Torque
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2025.3530325

HTS tapes are central to many future technologies and, as such, are the subject of significant research aimed to improve their properties. The production of long and high-quality <inline-formula><tex-math notation="LaTeX">\mathrm{(RE)Ba}_{2}\text{Cu}_{3}\mathrm{O}_{7-\delta }</tex-math></inline-formula> (REBCO) tapes being a challenging task, spools commercially available tend to be relatively short. Therefore, joints are critical points during applications, prompting extensive efforts to develop joints with low resistivity and good mechanical properties. Consequently, this study focuses on the recently developed copper diffusion bonding (diff. bond.) method. Using three different spools, the properties of the copper diff. bond. joints are compared to the solder joints. The results indicate that copper diff. bond. joints generally have lower surface resistivity compared to their soldered counterparts. Additionally, the results also showed a slightly better repeatability in joints resistance compared to the solder joints. On the other hand, one spool gave contradictory results having lower joint resistance and better repeatability for the soldering method which could not be explained.