Metallization of Carbon Fiber-Reinforced Polymers (CFRPs) Via a Two-Step Process of Electroless Plating and Thermal Spraying

Carbon fiber-reinforced polymers (CFRPs) are commonly used materials within the aerospace industry due to their low density and favorable mechanical properties. Nevertheless, while CFRPs are optimal for applications requiring low weight and high strength, applying thermal spray coatings to these composites presents significant challenges, including distortion, oxidation, and poor coating adhesion. This study presents a new technique that combines electroless plating processes and thermal spray for depositing metals onto polymer-reinforced composites. The process addresses both the technical hurdles of bonding dissimilar materials and the need for lightweight, durable composites in aerospace manufacturing with low cost of production and high scalability factor. Samples of low-melt polyaryletherletone thermoplastic polymer reinforced with carbon fibers aligned in the normal direction (ZRT film) are plated with Ni, Cu, or Ag to provide an adhesion layer for the thermal spray processes. Subsequently, pure Sn and Ti-6Al-4V are deposited on the samples using high-velocity air fuel and atmospheric plasma spray (APS) processes. Characterization of the samples was conducted to demonstrate the cracking in the Ti-6Al-4V coating on the Ni plating, which was attributed to the interlayers’ thermal properties. Additionally, the variation in the coating thickness according to the interlayer, the thermal resistance of the resulting samples, and the splat morphology of the Sn and Ti-6Al-4V coatings were evaluated. Overall, the Sn coating applied via APS on the nickel plating exhibited the optimal performance in terms of the evaluated parameters in this study.