Multiple pairs of bronze pieces were joined along a common seam and then exposed to Nb vapor via sputter deposition during heating at ∼715 ∘C to form a diffusion bond between the pieces. Polishing and alignment of the pieces created smooth surfaces normal to the Nb flux with seams perpendicular to the surface (i.e. parallel to the Nb flux). Conversion of Nb to Nb3Sn took place simultaneously with diffusion bonding, resulting in Nb3Sn thin films that coated bronze surfaces and spanned seams with uniform thickness. Characterization of superconducting properties via magneto-optical imaging suggests that supercurrent flows freely across the seam in several examples when cooled to 9 K and shielding or trapping low magnetic field. Modification of the process to coat the pieces with Nb prior to diffusion bonding and Nb3Sn formation resulted in varying degrees of seam coverage by the resultant Nb3Sn films. The pre-coating method did not produce any example with quality comparable to the examples obtained by the hot bronze approach. This work could enable new approaches to joining Nb3Sn materials in magnet conductor and RF cavity applications.
@article{arxiv.2603.18351,
title = {Nb$_3$Sn Films Exhibiting Continuous Supercurrent Across a Diffusion Bonded Seam},
author = {Andre Juliao and Wenura Withanage and Nikolya Cadavid and Anatolii Polyanskii and Lance D Cooley},
journal= {arXiv preprint arXiv:2603.18351},
year = {2026}
}
Comments
11 pages, 8 figures, submitted to Superconductor Science and Technology