Influence of Secondary Component Hardness when Cold Spraying Mixed Metal Powders on Carbon Fiber Reinforced Polymers

Tin has successfully been cold sprayed onto carbon fiber reinforced polymers (CFRPs) in previous studies at McGill University. To improve the coating conductivity for lightning strike protection (LSP) purposes, other metal powders (aluminum, copper and zinc) were added to tin and also sprayed. Results indicated that addition of any of the aforementioned secondary components (SCs) provided a noticeable increase in deposition efficiency (DE); it was hypothesized that a tamping mechanism might explain the improvement. In this study, aluminum and several aluminum alloys (5083, 6061, 7075) were mixed with tin powders to understand how the hardness of secondary components with similar densities may affect the DE. Mixing tin with other metallic powders is discussed and a refined “crack filling” mechanism related to SC hardness is explored as an improvement mechanism in the cold spraying of mixed powders on CFRPs.