Structural Analysis of Cold-Sprayed Nickel-Based Metallic and Metallic-Ceramic Coatings

In cold spraying, many factors, e.g., powder characteristics and compositions, spraying parameters, and post-treatments affect coating formation. Cold spraying is the optimal technique to produce highly dense coatings. Furthermore, denseness and impermeability are the criterions for the corrosion resistance of anodically protective coatings. Therefore, this study focuses on denseness improvement of cold-sprayed (CS) metallic coatings. The aim of this study was to characterize structural details of CS Ni, Ni-20Cu, Ni-20Cr, Ni-20Cr + Al2O3, and Ni-20Cr + WC-10Co-4Cr coatings in order to produce dense coatings by optimizing the affecting factors. Denseness of Ni coating was improved with optimized spraying parameters whereas denseness of Ni-20Cr coatings was increased with added hard particles in the powder mixture. In addition, denseness of Ni-20Cu coatings was improved by heat treatments. Denseness of the coatings is evaluated by corrosion tests. In addition, fracture behavior, microstructures, and hardness studies of the coatings are performed.