Dual Flow Cold Spraying Cu Conductive Coatings on Aluminum Components

Dual Flow Cold Spraying (DFCS) is modification of low pressure cold spraying to enhance a coating adhesion strength and diminish the internal stresses due to substrate intensive cooling. In this case, a surface preparation is very important for reliable adhesive bonding of cold sprayed coatings to the substrate. In this work, the grit blasting of Al alloy substrates with Al2O3 particles was studied and the roughness parameters Ra and Rt of the grit blasted surfaces were then measured. The influence of the roughening of the Al alloy substrate, and the resulting effect on the roughness of the Cu coating – Al alloy interface were studied. The results showed that variations of the DFCS had significantly affected the resultant Cu coating conductivity, density and adhesion strength. The adhesive strength about 120MPa was achieved due to effect of vortex formation at the interface. The specific features of the Cu coating-Al alloy interface topography were examined and discussed.