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 on the powder before and after deposition. Deposition of 2 copper powders on aluminium and Ta6V substrates has been done at different stagnation temperatures and pressure using nitrogen. The effect of the grain size distribution on the deposit efficiency and the mechanical properties of the coating are discussed .Hardness profiles show how the speed of the particles induces shot peenning the surface. The  interaction between the hot gas jet and the surface may recristallise the surface of the copper. The effect on the substrate hardness has also been investigated.