In this study, two copper powders with different size distribution are applied to aluminum substrates using cold gas dynamic spraying. The powders are sprayed with helium gas at ambient temperature and at 200 °C. Investigators measure oxide content in the powders and correlate it with in-flight particle velocity, deposition efficiency, particle deformation, and coating properties including microhardness, structure, and dislocation density.

Two copper powders were deposited with CGT3000 cold gas dynamic spray system on aluminium substrates. The X-ray diffraction patterns allow the characterisation of the microstructure such as grain size, strain in the coating and dislocation densities. Both powders and coatings have been fully characterised. Three methods have been used to interpret the X-ray patterns: the Warren-Averbach method, the Hall Williamson method and the modified Hall-Williamson method. A comparison between the state of the powders before and after deposition will give an insight on the metallurgical processes that take place during the formation of the coating. The influence of the grain size distribution will also be discussed. This article is a follow up of the publication done at ITSC2006: “Comparison Between Coatings from two Different Copper Powders: Mechanical Properties, Hardness and Bond Strength”.

Cold sprayed copper coatings have been widely studied but the effect of substrate properties and spraying conditions on the bond strength still needs further investigations. Using nanoindentation, it is possible to compare the effect of spray parameters on the change in hardness of the coating due to the difference in size distribution of the powder. Deposition of 2 copper powders on aluminium and Ta6V substrates has been done at different stagnation temperatures and pressures using nitrogen as process gas. Hardness profiles show how the speed of the particles induces shot peening effects on the surface. The interaction between the hot gas jet and the surface may modify the hardness profiles. The effect on the substrate hardness has also been investigated.