Metallurgical bonding between metal matrix and core-shelled reinforcements in cold sprayed composite coating

The cohesion mechanism of cold sprayed metal matrix composite coating reinforced with core-shell structured particles was studied. Al and Cu-Ni-coated diamond were used as the matrix and the reinforcement, respectively. The two components were found metallurgically bonded as evidenced by a formation of CuAl2 layer at the interface. Owing to this enhanced matrix-reinforcement bonding, the core-shelled diamond particles delivered superior deposition (i.e., higher diamond deposition efficiency, higher diamond content, better fracture resistance) than conventional uncoated diamond particles. Despite the metallurgical bonding, the coating cohesion strength was not improved, with the limiting factor likely being insufficient cohesion of the core-shelled diamonds. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.