1238 Deposition of fine metallic particle by cold spray
Details
To improve the deposition efficiency of 5 μm Cu particle onto metallic substrate by cold spray, optimization in nozzle design was performed by numerical simulation. In the spraying of copper particle onto normal steel substrate, unique lamellar-like microstructure was formed near the interface region in the steel substrate. To reduce the bow shock effect on the substrate surface region in cold spray process, special nozzle was newly designed. The deposition efficiency, Vickers hardness and coating adhesion strength increased significantly especially in the case of fine particle and higher pressure level of the working gas, while nominal particle velocity decreased with the special nozzle. Numerical simulation indicated that the pressure levels on the substrate surface decreased effectively in the nozzle newly designed. The results indicate that the decrease of particles velocity due to bow shock was suppressed effectively in the special nozzle as compared with conventional one.
