Contact welding strength measurement for metal electrode materials conducting inrush electrical current.

Contact welding is considered the major failure mechanism for electromechanical switch applications. There has been increasing demand to research the measurement method to characterize the anti-welding ability of metal electrode materials. In this paper, the contact welding phenomenon of closed electrodes is made to reoccur by using our novel designed test rig. The welding strength and welding area of typical electrode materials, including silver, copper, silver tin oxide, and silver nickel alloy, are explicitly measured and compared. In addition, the effects of electrical current and mechanical load force on welding strength and welding trace are presented. The calculation method of the threshold welding current is introduced for elastic contact situation in low current switching devices.