Deposition efficiency of low pressure cold sprayed aluminum coating

Low pressure cold spraying (LPCS) is different from high pressure cold spraying because it is capable of onsite operation with compaction system and flexible spray gun. However, the deposition efficiency is much low for efficient onsite reparation, it is important to know more about the influence of spraying parameters on deposition efficiency of LPCS. To verify the relationship between the spray parameters (temperature, standoff distance, powder feeding rate, and transverse speed) and the deposition efficiency, a DYMET413 commercial LPCS system was used to prepare coating under different parameters. The deposition efficiency increases linearly as the gas temperature increases. The optimal alumina content in powders is about 30%, the optimal distance is 25mm for the powder used in this study. The deposition efficiency of powder increases as the transverse speed of nozzle decreases. It is hard to predict the deposition efficiency by numerical methods since the deposition behavior in a composite powder system is influenced by a number of factors. The interaction between particles, the erosion effect of alumina and under critical velocity particles all can influence the deposition behavior.