Application of coatings for electromagnetic gun technology

Copper and aluminum are used extensively in various parts of electromagnetic (EM) gun systems. Copper is used for rail design in railguns because it has favorable electrical and thermal properties. Aluminum is used for armature and sabot fabrication because it is lightweight and has favourable thermal properties. Extensive degradation of the copper rail and aluminum armature occurs owing to the severe heating and thermomechanical deformation of these components during operation of the EM gun. In this research effort, several modification techniques were used to protect the rail and armature materials from these degradation processes. These include application of plasma source ion implantation (PSII) and ion beam enhanced deposition (IBED). By using these techniques, the copper rails and aluminum armatures were coated with TiN and TaN. Several characterization techniques were used to assess the chemical, mechanical and other properties of these modified surfaces. Optical microscopy, scanning and transmission electron microscopy and scanning auger spectroscopy techniques were also used. Microhardness measurements have also been performed. From the results of this preliminary investigation, it has been concluded that the surface properties of the coated rail and armature materials have been improved and the extent of wear and spark erosion from these surfaces has been reduced.<>