Residual Stress Measurement of Cold Sprayed Metallic and Ceramic Coating During Spraying

Cold spraying is a promising process to fabricate functional coatings. Because of the solid state particle deposition, the electrical and chemical properties of the cold-sprayed coatings are almost similar to the bulk materials. On the other hand, the mechanical properties are different from the bulk materials due to the severe plastic deformation of the particles. The residual stress can be considered to become additional reason for the coating property. However, the formation mechanism of residual stress is not entirely clear. In this study, the residual stress of metallic and ceramic coating was measured by two different way. In copper coating, the distribution of internal stress of the coating was examined by X-ray diffraction. As a result, the internal stress is non-uniform in the direction of coating thickness. Especially, there is disproportion of internal stress at the coating interface. It was suggested as a main factor for decreasing the adhesion strength. The stress generation during spraying was examined by a substrate deformation. In spraying, the stress value was strongly affected not deposition but collision.