Wear resistance of graphenic-nickel composite coating on austenitic stainless steel

Abstract In order to improve the tribological behavior of austenitic stainless steel, a novel composite coating based on reduced graphene oxide-Ni (rGO-Ni) is presented. These coatings were prepared by sol-gel using a mixture of Ni-rich xerogel films and reduced graphene oxide (rGO), with a heat treatment at 1000 °C for 1 h under an Ar flow. Raman spectroscopy confirmed that the rGO-Ni coating was formed. The rGO-Ni coating demonstrated an unusual surface topography, combined with multiple lamellar carbon growth and refined grains characterized by automatic crystal orientation mapping as determined through electron backscattered diffraction (EBSD). The rGO-Ni-composite coating exhibited a high elastic behavior from a multi-step nanoindentation with a depth of 900 nm and wear loss of ∼0.05 to 0.3 mm3 at 1 to 5 N. It was found that the increase on wear resistance was due to both the self-lubrication properties of the rGO and the harness of refined grains on the coating.