Microstructure and wear properties of aluminum/aluminum–silicon composite coatings prepared by cold spraying

Composite coatings containing aluminum and aluminum–11.6 wt.% silicon eutectic alloy phases of varying compositions were fabricated using cold spraying. Coating contained a uniform distribution of the two phases. The hardness of the coatings increased as the volume fraction of Al–Si in the coating increased. The length to width ratio of the splats was found to be larger for Al particles compared to Al–Si particles. Dry sliding ball-on-plate wear tests indicated that the wear volume loss was similar for the Al and Al/Al–Si composite coatings in spite of the increase in microhardness. This discrepancy is explained by the inter-splat delamination mechanism. The coefficient of friction of aluminum coating reduced on Al–Si addition.