Wear performance of graphene nano platelets incorporated WC-Co coatings deposited by hybrid high velocity oxy fuel thermal spray

WC-Co coatings have been used as wear resistant coatings in aero engines for decades, and research is still ongoing to further improve the performance of these coatings through compositional modifications to reduce wear. The coatings are used for unlubricated sliding wear protection in aero compressor parts such as; compressor, disc mid-span stiffeners and compressor aerofoils. In this study, two different graphene nanoplatelets (GNPs) were introduced into the WC-Co (88-12 wt %) coating through a hybrid thermal spray technique. Under the correct injection conditions, hybrid HVOF thermal spray leads to in-situ powder mixing which eliminates the need for premixed powder. The addition of GNPs into the WC-Co coating led to an increase in the porosity of coatings. Both GNPs improved the wear performance of the system against alumina and reduced damage to the counter surface. Against the WC-Co counter body, although in a few cases the GNP incorporated coatings had a higher wear rate, lower deformation on counter bodies were obtained. When wear of counter surfaces and coatings were combined, GNPs improved the wear performance of the system as a whole.