An investigation on erosion behavior of HVOF sprayed WC-CoCr coatings

Present work is an investigation of slurry erosion behavior of WC-CoCr cermet coatings deposited with two different WC grain sizes. HVOF thermal spray process was employed due to its high velocity and low flame temperature characteristics resulting in quality coating. HVOF spraying was assisted with in-flight particle temperature and velocity measurement system to control its heating. Slurry erosion testing was performed using a pot-type slurry erosion tester to evaluate slurry erosion resistance of the coatings. Two parameters were considered for testing viz. erodent particle size and slurry concentration. Surface morphology was examined using SEM images and phase identification was done by XRD. The erosion behavior and mechanism of material removal was studied and discussed based on microstructural examination. It was observed that WC-CoCr cermet coating deposited with fine grain WC exhibits higher slurry erosion resistance under all testing conditions as compared to conventional cermet coating.

► HVOF sprayed WC-CoCr cermet coatings were deposited with different WC grain size. ► An in-flight particle temperature and velocity measurement system was used. ► Erosion testing was performed using pot-type slurry erosion tester. ► Microstructural analysis had shown the different wear mechanisms. ► Fine WC grain coating exhibits high hardness and better slurry erosion resistance.