Experiments to measure wear in aluminum armatures

Although wear in sliding electric contacts has been studied extensively at low velocities (100 mis or less), the phenomenon constitutes uncharted terr itory at conditions of interest in railguns, A fundamental understanding of wear in railguns is important because loss of material from the armature i s one cause of transition from solid to arcing contact, and the resulting d eleterious effects on performance. Sixteen experiments have been conducted at the WT this year to address two fundamental questions related to wear: i ) what is the relative importance of electrical vs, mechanical heat generat ion at the rail/armature interface, and ii) what are the governing paramete rs that affect material loss from the armature. This paper describes the ex perimental techniques used to make wear measurements and discusses results from the experiments.