Application of laser shock adhesion testing to the study of the interlamellar strength and coating-substrate adhesion in cold-sprayed copper coating of aluminum

Compared with conventional thermal spraying, cold spraying should exhibit specific interlamellar (i.e., at sprayed particle boundaries) properties and coating-substrate interface due to certain characteristics of this process. These characteristics result from the spraying of particles at a low (cold) temperature combined with a high velocity, which leads to a low oxidation and a limited residual porosity in the sprayed coating. Due to the fairly recent development of cold-spray processing and to investigation difficulty in this field, very little is known about interface properties, primarily interlamellar strength and coating-substrate adhesion. In this study, laser shock adhesion testing, namely, LASAT, was developed to be suitable for the determining of both the interlamellar strength and the coating-substrate adhesion. LASATesting of cold-sprayed Cu onto Al showed that Cu-Cu interlamellar strength was about of the same order as that of Cu-Al coating-substrate adhesion. Results are discussed in the light of a parallel microstructural investigation into Cu-Cu and Cu-Al interfaces. More generally, this study demonstrated the feasibility of the LASATesting as a powerful tool for the measuring of adhesion, including in local zones. © 2004 Elsevier B.V. All rights reserved.