Fabrication of Aluminum Coating onto CFRP Substrate by Cold Spray

Abstract

Carbon fiber-reinforced plastic (CFRP) has a great potential application in aircraft fuselage due to its light weight, high specific stiffness and high specific strength. It is crucial to coat the CFRP surface with an electrically conductive material to avoid the damage from lightning strike. Cold spray process has been developed for metallic coating technique. In this study, aluminum coating was fabricated onto the CFRP substrate using interlayer was investigated. It was difficult to fabricate cold-sprayed aluminum coating directly on the CFRP substrate. Though smaller size aluminum particles could be deposited on the CFRP substrate, but the coating was peeled off when the thickness was around 30 μm. On the other hand, it was possible to deposit aluminum coating on the CFRP substrate by plasma spray process. Our proposed structure is using a thin plasma-sprayed aluminum interlayer on the CFRP substrate before doing the cold spray. The interlayer with larger contact area could retain on the substrate and able to facilitate the deformation of the next incoming cold-sprayed particles to build a thick coating. The volume resistivity of cold spray coating is lower than the plasma sprayed aluminum coating because of high process gas temperature in the latter case enhances the oxidation of sprayed particle. Therefore, lower process gas temperature should be used to fabricate lower volume resistivity coating on cold spray.