Erosive wear behavior of a WC-Ni composite coating deposited by cold spray

WC based composites are coatings that are widely used when erosion resistance is required. These coatings are conventionally fabricated by thermal spray processes. However, high temperature of thermal spray often results in decarburization and a deterioration of the erosion resistance. Cold spray has potential to deposit WC based composite coatings and retain the composition of initial WC feedstock. In this study, feasibility of cold spraying WC-Ni coatings was explored. The WC and Ni powders were fed to the gun from separate hoppers with independent feed rates and a composite coating of WC 10vol.%- Ni was sprayed. Microstructural characterization including morphology of Ni splats and retention, distribution, and fragmentation of WC was performed by SEM. Mechanical properties of coatings were investigated by nano- and micro-indentation. In order to assess erosive wear behavior, the material loss mechanisms of WC-Ni coating subjected to solid particle erosion (SPE) was investigated. Microstructural analyses and wear loss measurements were conducted to study the erosive wear behavior at low and normal angle of incidence. Correlations between mechanical properties of the coatings and the erosive wear resistance are discussed with consideration to the effect of deformed cold sprayed microstructure and WC reinforcing particles on erosive wear behavior.