Laser-induced damage in cold-sprayed composite coatings

Ag–Ni composite coatings were achieved using the cold spray process. In this work, two blends were sprayed to lead to coatings with different mechanical properties, which corresponded to either a fine or a coarse microstructure. These coatings were studied using SEM and X-ray microtomography (XMT) to determine the best coating quality through characterization of particle-to-particle bonding. The fine microstructure showed better properties than the coarse microstructure. id time-consuming characterization techniques such as SEM and XMT, an innovative laser characterization test was developed. The principle of this test is based on the thermal shock-induced by a laser pulse at the surface of the coating. Thus, particle interfaces were stressed and cracking damage could occur. SEM observation of cross-sections and top views was carried out to rank the coatings as a function of the generated damage. The influence of heat treatments was also studied. ance the approach, thermomechanical simulations have been performed on a real meshed microstructure. The influence of layering effect in the cold spray was shown to be detrimental due to local concentrated stresses.