The Effects of Lubrication on Electroplated Tin Surfaces: A Systematic Approach by DOE-Methodology

The reliability and the functional electric capability of a separable connector contact strongly depend on the tribological properties of the used contact surfaces. The present study addresses the characterization and comparison of these properties of electroplated matte and bright tin surfaces with a special focus on lubrication. Utilizing statistical design of experiments (DOE) methodology and a specially developed tribometer to measure friction forces and contact resistance characteristics, the effects of lubrication on the contact performance are investigated in detail. During the friction experiments several parameters such as lubrication, normal load, sliding distance and velocity were systematically varied. The investigations involved a determination of the coefficient of sliding friction and contact resistance with contact geometries and surfaces used in a typical separable connector contact. It was found, that from a tribological point of view the effectiveness of the lubrication is higher for bright tin than for matte tin surfaces. Lubricated bright tin surfaces excel by their extremely low coefficient of friction, but due to unstable and elevated contact resistance characteristics lubrication of bright tin surfaces is finally not recommended. Based on the DOE-analysis we can furthermore determine the influence of normal load, sliding distance and velocity, to identify parameters for improving the wear characteristics of lubricated tin surfaces.