Metallurgical study and tribological properties of edge card connector spring/tab interface

Summary form only given, as follows. The influence of composite metallurgical structure on the tribological behavior of an edge-card connector was studied. The study centered on the metallurgy of the card tab, which is a multilayer structure consisting of a printed circuit board with an overplated copper layer, nickel, hard gold, and soft gold. These experiments were performed under both dry friction and thin-film polyolester lubricated conditions. The thickness of each was found to alter the frictional characteristics of the surface. The experimental data were found to agree with Finkin´s theoretical model for solid-film lubrication. The role of the soft-gold layer was identified as a friction/wear riser, rather than a solid lubricant. It was found that the addition of a minimum layer of lubricant can provide lower friction on contact surface and eliminate fretting wear. The lubricant also made the behavior less sensitive to the metallurgy. When the amount of lubricant was increased the coefficient of friction stayed almost the same from thin-film to flooded conditions. The difference in wear between the dry and thin film lubrication conditions was minor.<>