Materials evaluation for use as plasma brush electrodes with hybrid armatures

There is a strong motivation to develop a railgun armature which will function as a nonarc, solid contact armature throughout the complete projectile acceleration to launch process. Solid contact armatures are more efficient in converting electrical to kinetic energy and generally cause less erosion of the rail. Considerable effort is being directed towards designing armatures capable of reaching 3+km/s while avoiding transition from a solid to an arcing contact. While nearly 2 km/s has been achieved in a nonarcing contact, it may be inevitable that an arcing contact will be unavoidable during the final acceleration to full desired velocities. At present most solid armatures are fabricated from aluminum or copper. While aluminum or copper might be good choices for solid contacts, this paper introduces the possibility that different materials will better serve as electrodes in arcing contacts.<>