Experiments to measure wear in aluminum armatures [in railguns]

Although wear in sliding electric contacts has been studied extensively at low velocities (100 m/s or less), the phenomenon constitutes uncharted territory at conditions of interest in railguns. A fundamental understanding of wear in railguns is important because loss of material from the armature is one cause of transition from solid to arcing contact, and the resulting deleterious effects on performance. Sixteen experiments have been conducted at the IAT this year to address two fundamental questions related to wear: (1) what is the relative importance of electrical vs. mechanical heat generation at the rail/armature interface?; and (2) what are the governing parameters that affect material loss from the armature? This paper describes the experimental techniques used to make wear measurements and discusses results from the experiments.