Investigation of Orthogonal Experiment for Fabrication of a Soldering Joint for a 4-T HTS Coil

The joining process of individual BSCCO conductors is inevitable because the double pancake coils need to be connected with each other. Since the resistance characteristics of the joint can affect the stability of nuclear magnetic resonance system seriously, we did a research on soldering joint in this paper. As resistance characteristics of a soldering joint can vary with conditions such as joint length, thickness, temperature, and so on, we conducted short sample joint experiments with orthogonal experimental design. The significance of each condition's influence was quantitatively calculated, and an appropriate soldering condition was put forward, under which the lowest joint resistance can be obtained. We also applied this appropriate soldering condition to fabricate joints for a 4-T high-temperature superconductivity coil and tested its practical electrical properties.