| Summary: | Bi-2212/Ag superconducting wires are being considered as key conductor candidates for the development of high field magnets (up to 25 T), but it is recognised that a reliable joining process between these wires is a critical challenge for most high-field applications. This work focuses on the design and testing of jointing processes between multifila-mentary Bi-2212 wires to make persistent mode joints using soldering techniques. The ability of several different su-perconducting solder alloys from the PbBi and SnInBi sys-tems to remove and replace the Ag matrix in fully reacted Bi-2212 wires has been explored. The SnInBi lead-free sol-der was found to be relatively effective at removing the Ag matrix, but does not make good contact with the Bi-2212 filaments. PbBi solder wets the Bi-2212 filaments more ef-fectively, but is slower at removing the Ag matrix. There-fore, a two-stage process has been developed using molten Sn to first remove the Ag matrix followed by PbBi to re-place the non-superconducting Sn. Joints made using this two-stage process have higher critical currents (133 A in self-field and 4 K) than joints made using PbBi alone (120 A in self-field 4K).
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