Accelerated Lifetime Testing of the Tribo-Electrical Properties of a Lubricated Tin Contact System

For the development and validation of lubrications for tin contact systems in connector applications fundamental, systematical investigations by means of DOE are inevitable. Such investigations are performed on abstracted model contacts, whereas different lubricant modifications, contact geometries, layer thicknesses and load collectives considering both micro- and macrotribological loads must be considered. Once a suitable solution guaranteeing a reliable tribo-electrical function over the contact lifetime is found, the results must be validated within product tests exceeding the normative requirements. This work presents the results of the development and validation process of a lubricated tin contact system for a PCB connector, considering both fundamental DOE investigations on model contacts and the validation for the finished product. For the latter, methods of accelerated lifetime testing were used to investigate aging mechanisms such as wear, fretting corrosion or thermal aging. Special focus was laid on the influence of current loads on the aging under thermal stress and corresponding relative movements. The results reveal significant differences between standardized and customer-specific test setups.