Microtexture and electrical and mechanical properties of the cold-sprayed copper deposit

Cold-spray (CS) technique is a new coating technology that is based on the high-velocity impinging of small solid particles on a substrate. The CS technique can make a thick deposit with less heat influence. Recently, this CS technique has been applied to the formation of an electrically conductive copper layer on dielectric materials such as polymers or ceramics. Previous researches show that the deposits made by the CS technique have high strength and residual stress comparing with bulk copper. However, since the deposits show brittle fracture and cracks propagate along the interfaces of the deposited particles, the deposits can not be applied to the products for which high reliability is indispensable. Therefore, it is very important to clarify the dominant factors which change the crystallinity of the deposits comparing with that of bulk copper in order to improve the quality of the deposits. One of the important factors should be the integrity of the interfaces between the deposited fine particles. This study is to evaluate the micro-texture and physical properties of the cold-sprayed copper deposit. Electron back-scatter diffraction method was applied to the evaluation of the crystallinity of the deposits. In addition, the relationship between the crystallinity with both mechanical and electrical properties of the deposits was clarified quantitatively.