Investigation of Wetting Property and Joint Fabrication Pressure on the Resistance and Microstructure of Soldering Joints for REBCO Conductors

Abstract

In this work, we systematically investigate the relationship between wetting property, joint resistance, and microstructure for soldered rare-earth Ba₂Cu₃O_7-x (REBCO) joints using six different surface conditions and three different fabrication pressures. As expected, increasing fabrication pressure can decrease the joint resistance. However, it is found that the wetting property can cause significant differences among the different surface conditions. Moreover, a poor wetting property can directly cause higher joint resistance, even under high fabrication pressure. This can partially explain the difference in the joint resistance found in the literature. At the same time, microcomputed tomography was introduced in the investigation of the REBCO joint. This enables nondestructive characterization of the joint microstructure, which can help us better understand the factors influencing microstructure and joint resistance.