Design and Performance of Armature Surface Coating for Electromagnetic Launcher

Armature is the key component of electromagnetic launcher (EML), but in the process of launching, its working environment is bad and the surface is seriously worn. Excessive wear will seriously weaken the mechanical properties of armature and affect the launching safety. Therefore, it is necessary to deal with the surface state of armature to reduce wear and improve the performance of armature. First, the properties of the candidate materials are analyzed. According to the principle of maximum current carrying capacity per unit mass, aluminum is the most suitable material for armature manufacturing. At the same time, the defects of material selection in single material system are pointed out. Second, based on the above problems, the surface coating design scheme is proposed. From the point of view of material melting point and hardness, it is proposed that tungsten can be used as the coating material for armature surface. According to the wear amount of armature tail under launch condition, the coating shape and thickness are designed. The best coating forming process is determined by calculating the shear force between coating and substrate; finally, the effect of the coating on the electric contact performance, system efficiency, and projectile gouging threshold velocity is analyzed. The results show that the maximum shear force between the coating and the substrate is above 171 MPa under the launching condition, and the laser cladding technology can meet the process requirements. After coating treatment, the contact resistance between the armature and rail (AR) increases by 6%, which has little effect on the system efficiency. Although it will affect the projectile gouging threshold velocity, it can be improved by modifying the tungsten coating or rail surface treatment. The analysis results are of great significance to reduce the armature wear, improve the contact performance between the AR, and improve the launch safety.