Tribo-erosion performance of few HVOF coated micron layers subjected to equi-sized slurry particles

A comparative study on characteristic and erosion behavior of the 4 different high velocity oxy-fuel sprayed WC-10Co-4Cr, Colmonoy-88, Stellite-6 and Ni-Cr coatings on pump impeller stainless steel (SS 410) has been evaluated in the current investigation. First, the various micron layers were characterized by using energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), scanning electron microscopy (SEM), micro hardness and micro roughness, and after that were subjected to erosion wear testing. Ducom slurry pot test rig with fly ash as erodent was used for erosion wear experiments, and the impact of four process parameters, namely, rotational speed, average particle size, solid concentration and time duration on slurry erosion of SS 410 were investigated. From erosion wear experimentation, it was concluded that the erosion wear highly depends upon the effecting parameters. The erosion resistance of coatings is found to be in following order WC-10Co-4Cr > Colmonoy-88 > Stellite-6 > Ni-Cr. It might be because of the higher hardness of WC-10Co-4Cr coating as compared to other coatings. Further the results show that the erosion wear of WC-10Co-4Cr, Colmonoy-88, Stellite-6 and Ni-Cr coatings was observed maximum at impact angle of 30 degrees, 45 degrees, 60 degrees and 90 degrees respectively.