Coefficient of Friction Measurement in the Presence of High Current Density

On the microscale, armature-rail interface contact is accomplished through surface asperity interaction. In this imperfect contact model (a version of the Bowden-Tabor model), we postulate the coexistence of one or more contact regimes, such as solid-solid contact, liquid-metal lubricated contact, and arcing contact. We are developing microscopic models and experimental apparatus to study this postulate. This work, in particular, describes the experimental apparatus developed to assist in the investigation of possible contact regimes and presents preliminary data that indicate a possible decrease in coefficient of friction in the presence of high current density when compared to a no-current condition