Cold Spray of Mixed Sn-Zn and Sn-Al Powders on Carbon Fiber Reinforced Polymers

Carbon fiber reinforced polymers (CFRPs) have been increasingly used in the latest generations of aircraft and helicopters for lightweight purposes, but this leaves vulnerability against lightning strike. Cold spray is one coating approach to metallize the polymers, thus making them lightning strike proof. It has been reported that direct cold spray of metals onto CFRP is difficult. However, research at McGill University has shown that tin coatings can be cold sprayed on CFRP, but the deposition efficiency is very low. In this work, aluminum and zinc powders were mixed with tin to investigate the effect of mixing on deposition efficiency of the coating. The mixed metal powders were cold sprayed on CFRP with a low-pressure cold spray system at various conditions. It was found that the addition of aluminum or zinc resulted led to increased deposition efficiencies compared to pure tin, but there are many differences in the details of the effect of Al and Zn additions on the deposition characteristics. The deposition mechanism of the mixed metal powders on CFRP is discussed, and the effect of mixing powders on the deposition efficiency is evaluated.