Deposition Behavior of Copper Particle Onto Flat Substrate Surface in Cold Spraying

Cold spray is a promising process for fabrication of high quality copper coatings. However, it is necessary to improve some properties especially of adhesion strength and to clarify the deposition mechanisms of solid particles. In this study, deposition behavior of cold sprayed copper particles was observed and the adhesion strength of the deposited particles was evaluated. Self designed cold spray equipment was installed in our laboratory and deposition behavior of sprayed individual copper particles on mirror polished stainless steed substrate surface was fundamentally investigated. Adhesion strength of individual particles deposited on the substrate was evaluated by nano-scratch test. Morphology of cold sprayed particles was almost same as each spraying conditions. The adhesion strength of the deposited particles was approximately 70 MPa. It was much higher than that of coating fabricated with same spraying conditions. It is considered that the cold sprayed particles are bonded by counter diffusion of the coating and the substrate materials in their interface. The diffusion is one of the most important factors to deposit the particles in cold spray process.