Numerical Examination of the Bonding Formation and Coating Build-up in Liquid Cold Spray

Cold spray process uses low-temperature, high-velocity gas to deposit solid-state particles without oxidation nor phase transformation. For the technology to become more cost-effective, feedstock material costs must first be reduced by the ability to spray coarser particles with a wider size cut. To achieve this goal, liquid cold spray techniques (LCS) was developed by using water as the propellant. Although LCS was successful in fabricating metallic coatings, the use of water as the propellant negatively affects the deformation of the deposited particles. Due to particle high strain rate deformation, elastic-plastic numerical methods can be used to analyze it. In this paper, the consequences of wetting the particle and substrate on their deformation is investigated. The results show that the water wetting the particle is trapped in the contact area which negatively affects the adhesion of the particle. As a way of better understanding water layer effect on the adhesion, numerical method is used to examine the failure of particle and substrate oxide layer. Ultimately, it is necessary to determine whether impinging wet particles on a wet substrate affects the porosity of the samples. The results show that water is trapped between deposited particles, affecting the density of as-sprayed samples.