A low-friction graphene nanoplatelets film from suspension high velocity oxy-fuel thermal spray

The addition of graphene-based nanomaterials is known to improve the tribology properties of materials by lowering the coefficient of friction and reducing wear. The covering of small areas with thin graphene-based films is routinely carried out; however, a fast and efficient way of covering large areas represents an outstanding challenge. Here we present a method for the deposition of graphene nanoplatelets (GNPs) on stainless steel substrates based on suspension high-velocity oxy fuel thermal spray. GNPs were radially injected into the combustion jet, providing sufficient momentum and moderate heat transfer to facilitate effective bonding with the substrate. Upon unlubricated ball-on-disc wear testing against an alumina counterbody, GNPs undergo gradual exfoliation, covering the substrate and thus lowering the friction coefficient (