Abstract
The deposition mechanism of cold spray process has not been fully understood at present. It has been widely accepted that particle velocity prior to impact is one of the most important parameter for cold spray process, and bonding occurs when the impact velocities of particles exceed a critical value. For cold spray, the splat is the basic element of coatings and determines the coating properties, such as porosity, bonding strength. Therefore, the study of splats is helpful to understand the deposition mechanism of cold spray process. In this work, copper powder was utilized to prepare splats on three substrates, aluminum alloy, copper and stainless steel, under different spray conditions. Particle velocities were measured by DPV-2000 system experimentally. The morphologies of copper splats and cross sections were characterized by scanning electron microscope (SEM). In order to control the cross sections of splatted particle passing the center of particle as much as possible, the cross sections were polished by a new method with ion beam. The influences of particle velocity on cold-sprayed splat morphologies and cross-sections were discussed.
