Fast joining YBCO bulks with melt Ag doped Y-Ba-Cu-O solder

Y-Ba-Cu-O is a promising high temperature superconductor material because of its good electrical and magnetic properties. However, large and complex bulks cannot be made directly, and joining is a good way to solve this problem. Joining Y-Ba-Cu-O with filler material was widely used and reported, but sliced melt solder was rarely reported, especially the one that required relatively short time. In this paper, sliced melt Ag doped Y-Ba-Cu-O was used as filler material and the joining time is relatively shorter compared with most of the published paper. The melt solder was fabricated and tested, the melting temperature is 975°C and there is much less pores found in the solder compared with the sintered solder. The bonding result is very encouraging: the superconductivity recovery ratio is 97.3%, which is about 5% higher than as sintered filler material. The microstructure in the bonding zone is very similar to that in the base material, no Y₂BaCuO₅ (Y211) phase accumulated during the joining process, which reveals that high quality superconductive bonding was achieved.