Research on Soldering Technology of YBCO Splice Joint

Due to the limitations of the YBCO tape production process, the length of a single YBCO tape is restricted. A joint is created to unite two YBCO tapes when winding superconducting coils with short YBCO tapes. Superconducting magnet functioning is adversely affected by poor joint quality. Soldering experiments of short YBCO–YBCO splice joint samples are performed utilizing a self-made joint soldering device in order to investigate the impact of various parameters on the quality of YBCO tape to YBCO tape splice joints. The influence mechanisms of seven parameters, including soldering temperature, current, holding time, joint length, pressure, type of solder, and type of flux, were examined using the design of experiment approach. In addition, a technique is suggested to improve the conditions for testing and soldering success rate by fitting the response function of various influencing variables through a small number of trials. With a success rate of greater than 96%, the splice joint resistivity at zero field and 77 K was stabilized below 80
${\rm{n\Omega }} \cdot \mathrm{c}{\mathrm{m}}^2$
.