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

In previous studies at McGill University, tin has successfully been cold sprayed onto carbon fiber reinforced polymers (CFRPs) and, with the idea of improving the coating conductivity, 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 deposition of tin on CFRPs. The top-surface and cross section of the coatings were examined, and DE and coating thicknesses were measured. Profilometric data were acquired on some coating top surfaces, as well as directly on some substrates after coatings peeled off. 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.