Evaluation of Parameters for Assessment of Inter-Splat Bond Strength in Cold-Sprayed Coatings

The quality and performance of cold spray coatings are largely determined by the extent and strength of bonding between the adjacent splats. Usually, the extent of inter-splat bonding is only qualitatively estimated by examining the polished and etched sectioned surfaces of the coated sample. Thus, there is a clear need for indirect techniques to quantitatively estimate the extent of inter-splat bonding so that they can serve as quality control tools. In this study, elastic modulus, electrical conductivity, and critical load for inter-splat debonding as determined using a scratch test are considered as possible parameters for the estimation of the extent of inter-splat bonding using four different cold spray coatings (Ag, Cu, 316 Stainless Steel, and Zn) as model coatings. It is demonstrated that all the three parameters are capable of quantifying the extent of inter-splat bonding.