Resistance Welding of Dissimilar Metals

This paper is concerned with the resistance welding of various dissimilar metals, primarily component parts such as ribbons, leads, and cases to one another. The study was made and is being continued to improve production welding in the manufacture of aluminum electrolytic, and tantalum capacitors. Resistance welding is primarily used by capacitor production because it is a fast, economical process, which lends itself readily to automation. The welds associated with the higher conductive, dissimilar metals are not fusion welds, but can be described as solid state bonds. There are some inherent defects in the solid state bond that do not normally affect the fusion bond. These are: (1) crystal lattice defects such as vacancies, (2) crystal deformation, and (3) atomic size mismatch. In spite of these inherent defects, excellent AQL´s can be expected, provided certain requirements are met. The requirements include an overall program of weld design, equipment, schedules, process control, and component design, materials, and material control.