Residual stress and adhesive/cohesive strength in cold-sprayed coatings are extremely important factors, and the balance between them can be a determining factor in coating failure, such as by delamination or cracking. Dominated residual stress to bonding stress should lead to coating peel off from its substrate. Up to now, it is still difficult to measure the residual stress of cold-sprayed coating especially inside it. In the present study, a high-energy X-rayed beam was utilized to penetrate the cold-sprayed coatings and the change of its diffraction angle can be detected. This gave a way to measure the residual strain inside the cold-sprayed coatings. With the scanning of the X-rayed beam and the detector at different locations, the strain of cold-sprayed coating at 2 directions can be obtained. Moreover, the residual stress of cold-sprayed coating can be calculated with the measured strain.

A kinetic metallization technique, which is one of the cold spraying systems, has been studied as a new coating system for metallic bond coats of thermal barrier coatings for components used in hot section of advanced gas turbines. In this study, in-situ residual stresses in atmospheric plasma sprayed yttria-stabilized zirconia (YSZ) top coating with two different bond coat spraying systems, deposited by a low pressure plasma spraying and a cold spraying, were evaluated and compared by thermal cycle tests. From the results of 1st thermal cycle, in the case of the plasma sprayed bond coat, a tensile residual stress was observed at the elevated temperature up to 400°C. Relaxation of the residual stress was started beyond 400°C. On the other hand, the gradual increase of tensile residual stress was observed up to 1000 °C in the case of cold sprayed bond coat. In addition, transition behaviors of residual stress between plasma sprayed and cold sprayed coatings were varied in 3-thermal cycles.