The barrel life of a solid armature rail gun is a critical issue. Arcing along the barrel pathway at the interfaces between the armature and the rails produces severe damage. The ability to protect the rails and yet provide sufficient electrical contact to sustain arc-free high-current flow is desirable. This thesis investigates the use of liquid metal as an interface material between the sliding electrical contact surfaces of the armature and the barrel rails. Experiments were conducted with the Naval Postgraduate Schoolαs 4-inch Rail Gun and liquid metal interface coatings were applied to the armatures. Results indicated that the liquid interface protects the rails and projectile surfaces for static electrical contact. Apparatus has been design to investigate sliding electrical contact between armature and rails in a controlled manner. New rails with a novel Adamy-Maier grooved rail design were fabricated to facilitate coating rails. Various groove patterns have been designed to control the current flow through the rails and across the interface surfaces, while maintaining lateral stability and interface integrity. These experiments are still in progress at the time of this writing.
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