Investigation on the influence of particle preheating temperature on bonding of cold-sprayed nickel coatings

Spherical nickel (Ni) particles were deposited onto aluminium (Al) substrates in order to investigate the deformation and bonding mechanisms of particles as a function of their temperature. The particles were preheated to 473 K, 673 K and 873 K prior to be sprayed onto the substrates. The microstructure and microhardness of the coatings were evaluated. Results show that the microhardness of the coatings deposited using preheated particles decreased due to the elimination of work hardening after coating deposition. The relationship between the adhesion strength of coatings and the preheated temperature of particles was also discussed. The result shows that a stronger adhesion strength can be obtained using preheated particles. However, the adhesion strength decreased when the preheated temperature of particles was too high. Ni-Al diffusion layer generated during annealing process was also used to explain the effect of particle preheating temperature on the bonding mechanism of coatings. (C) 2016 Elsevier B.V. All rights reserved.