▎ 摘　　要

In thermally sprayed tungsten carbide-cobalt (WC-Co) coatings, the hard WC particles perform as the wear-resistant part, while the cobalt act as binder and provides toughness. Due to their excellent properties, thermally sprayed WC-Co coatings have been widely used in many industrial applications requiring sliding, abrasion, erosion resistance, and fretting. The Tribological characteristics of nanostructured WC-25%Co coatings obtained using high velocity oxy-fuel (HVOF) spraying were investigated. The feedstock powder of nanostructured WC-25%Co used to deposit the coatings was mixed with the reduced graphene oxide (rGO) as an additive at three different weight percentages proportions of 0.5, 1.0, and 1.5 wt% to investigate its effect on the characteristics of coatings. The microstructural and tribological characteristics of obtained coatings were evaluated. The worn-out surfaces of coatings in the wear track were characterized to identify the wear mechanism involved. It is found that abrasion wear is the most predominant wear mechanism causing the wear loss of coatings. It is also found from wear track analysis that wear tracks are evident at 1.5 and 1.0 kgf loading conditions, while they are very lightly visible at 0.5 kgf loading condition because of lesser impact of WC ball over the coating surface. Microstructural characteristics of the coatings are altered, and the rGO bridges in the middle of the splats are also identified in coating's microstructure. Also, a significant improvement is observed in the microhardness and surface roughness with rGOs reinforcement in the nanostructured coatings.