The influence of physical separation between cycles on the wear behavior of connector contact materials

The wear behavior of connector contact materials has traditionally been evaluated using reciprocating motion with continuous contact between the rider and flat up to the end-of-test. Initial contact establishes the location of the wear tracks and spots. Connector members, on the other hand are physically separated between cycles. Further, because of manufacturing tolerances, the wear tracks for each cycle may not coincide. This study characterizes the influence of physical separation between cycles on the wear behavior of connector contact materials. Both electroplated and metallurgically processed contact materials were cycled under load first without, then with, physical separation between cycles. Two mating geometries were employed representing "preferred" and "troublesome" contact geometries as defined by the magnitude of Hertz stress. Methods of evaluation included determination of the coefficient of friction and quantitative metallography. It was found that, high contact material hardness reduces the initial coefficient of friction but does not assure acceptable wear behavior, the wear behavior of each material correlated with a basic model, physical separation can lead to multiple wear spots on the riders forestalling the onset of asperity junction growth, and the mating geometry did not affect wear behavior.