The effects of rail coatings on melt-wave erosion in block armatures

In this paper we investigate the influence of different rail coatings on melt-wave erosion (MWE) in block armatures. A two-dimensional numerical model is developed and the finite difference method is used to simulate the transient evolution of MWE. The results of numerical calculations show a local concentration of current and joule heating at the interface, and MWE occurs at the trailing corner of the block armature. Five different pure metals are used as the rail coatings to improve the launching performance of the railgun. Important electrical parameters of coatings are analyzed through comparing the axial erosion distance and the vertical gap thickness. It is observed that the coating materials with a higher electrical conductivity than that of rail material are helpful to delay the spread of MWE. The results are inspiring and contribute to apply the rail coatings to solid-armature railguns.