Characteristics of reduced graphene oxide (rGO) mixed HVOF-sprayed nanostructured coatings

ABSTRACT High-velocity oxyfuel (HVOF) sprayed ceramic coatings possess less porosity and exceptional cohesive strength as compared to the air plasma sprayed ceramic coatings. In particular, the HVOF-sprayed tungsten carbide-cobalt (WC-Co) coatings have the disadvantage of unexpected brittle fracture. These coatings usually fail at higher levels of stress because of their lower fracture toughness that results due to decarburization occurring during the deposition of the coatings. In this work, the HVOF-sprayed nanostructured WC-25wt-%Co coatings have been investigated with and without the addition of rGO. It was found in the microstructure of 1.5% rGO-added WC-25wt-%Co coatings that the rGO has been pulled out from the matrix and wrapped in the fractured regions. It was also observed with an increasing percentage of rGO addition that the porosity in the WC-25wt-%Co coatings has been reduced due to a reduction in the number of pores.