Performance of thermal-sprayed WC-Cr 3 C 2 -Ni coatings in slurry erosion for hydrodynamic turbines

Hydrodynamic turbine and slurry pump components are frequently influenced by severe wear due to the impact of solid particles present in the water. A WC-based coatings deposited by thermal spray techniques is known for the protection against slurry erosion. In the present work, WC-Cr3C2-Ni powder was sprayed on a turbine steel substrate using high-velocity oxy-fuel (HVOF) and atmospheric plasma spray (APS) techniques. Microstructural and phase constitutions of as-sprayed coatings were examined. The effect of speed, slurry concentration and particle size on slurry erosion resistances of both coatings and substrate materials was comparatively studied in a slurry pot erosion tester. The results exhibit that the HVOF coating has better properties in terms of density, micro-hardness and slurry erosion resistance than those of APS coating. The improvement in slurry erosion resistance of bare turbine steel by using APS and HVOF coatings is approximately 37% and 62%, respectively.