Enhancing connector reliability by using conducting polymer materials to minimise contact fretting

A typical luxury car has in excess of 400 electrical connectors with over 3000 individual terminals. Tin plated terminals are still widely used because of particular technical and commercial advantages, but this type of plating is susceptible to fretting corrosion leading to intermittent high contact resistance. This phenomenon is well known to be the main failure mechanism impairing electrical system reliability.

Novel contact materials, such as conducting polymers, are investigated in this study as a possible replacement for tin plated terminals used in the automotive wiring harness. The design concept behind using a polymer contact is to minimise any fretting motion between two contacting components by the polymer flexing or bending. Fretting studies are conducted on the polymer–tin interface showing the improved mechanical and electrical behaviour of this novel interface. A mechanical model of the polymer interface is developed showing its behaviour under fretting conditions. To achieve a “zero fretting” condition, the elastic force opposing the fretting action of the deflected polymer must be lower than the frictional force at the contact.