Durability of some asymmetrical contact pairs for connector application

Overview & Synopsis

Reliability of connectors is still a major concern for end users in many applications. One way to improve it is to optimize the surface coatings deposited on base substrates. Although gold remains the most widely used contact plating material, many alternative coatings have been developed in the past or recent years. Among these alternatives are silver final coatings and gold flash over palladium-nickel plated alloy. The properties of these two platings have been mainly investigated in symmetrical configurations where male and female contacts have similar deposits. In this work, asymmetrical configurations - where platings on male and female contacts are dissimilar - are studied. Wear behaviour was investigated with friction and fretting tests. The aim was to characterize the role of the various layers on the wear performances of contacts. Contact resistance behaviours were measured and correlated to the wear tracks investigated with various techniques such as SEM, EDS and 3D-Profilometry. It is shown that in some cases dissimilar final coatings on male and female contacts can significantly improve durability.