Solid particle erosion of HVOF sprayed WC-Co/NiCrFeSiB coatings

It is a well-known fact that materials that consist of both brittle and ductile constituents can show erosion behavior in either a ductile or a brittle manner. The high-velocity oxy-fuel (HVOF) sprayed WC-Co/NiCrFeSiB coatings on GrA1 boiler tube steel exhibit composite ductile and brittle modes of erosion under angular silica sand erodent of size 125-180 μm impacted at 40 m/s. The HVOF spraying leads to a high retention of WC in the coating matrix accompanied with lower porosity. The as-sprayed as well as eroded coatings have been characterized using scanning electron microscope and optical profilometer.