Materials Considerations in using Voltage Drop for Power Rating

Voltage drop, and change in voltage drop after aging, are considered in rating the performance of gold plated power contacts. In this case, samples are exposed to high current cycling at current levels that produce very high temperature rises. This created conditions that caused degradation due to thermal aging and possibly electro- migration. It is shown that the failure criterion for gold is similar, but not equal, to tin. Based on these results, it's concluded that loss of metallic contact regardless of plating type is the common factor in the tin and gold performance. Moreover, current density and contact voltage are discussed as basic physical parameters that provide links to aging and failure criteria. The aim is to develop a method using voltage drop for various contact materials to quantify power rating of contacts for reliable use in the field.