The effect of the standoff distance on the microstructure and mechanical properties of cold sprayed Cr3C2-25(Ni20Cr) coatings

Abstract In this study, coatings were obtained by spraying two Cr 3 C 2 -25(Ni20Cr) powders, possessing different morphology and grain size distributions, on an Al 7075 alloy substrate at various standoff distances. The applied powders and process parameters allowed to produce deposits characterised by a compact microstructure and negligible porosity. Depending on the used powder, the obtained coatings showed variations in surface roughness and how the Cr 3 C 2 particles were incorporated into the Ni20Cr matrix. The standoff distance significantly affected the coatings microstructure, mechanical properties, and deposition efficiency. The coatings obtained at a standoff distance of 50 mm were characterised by the highest hardness and amount of incorporated Cr 3 C 2 particles. In turn, coatings sprayed at the distance of 30 mm possessed the highest microhardness and Young modulus, as well as lowest surface roughness.