▎ 摘　　要

Graphene is an emerging solid lubricant that improves the tribological properties of materials by lowering the coefficient of friction and reducing wear. However, the industrial-scale fabrication of graphene is still limited by the lack of a fast, inexpensive, and efficient coating deposition method on large areas. Here, we developed a new one-step process in which graphene nanoflakes (GNFs) are synthesized in-flight by methane decomposition using an inductively-coupled plasma (ICP) torch and are uniformly sprayed over stainless-steel substrates with a deposition rate of 25 mu m/min. The uniform nanostructure and quality of the GNFs are demonstrated by transmission electron microscopy, scanning electron microscopy and Raman spectroscopy. Using a ball-on-three-plates tribometer, the friction coefficient of the GNFs-coated steel decreases significantly from 0.90 to 0.17 (10 N load) and the corresponding wear rate decreases by a factor of similar to 10 compared to the uncoated steel. The wear results are discussed in the framework of a frictional behaviour mechanism and we argue that the wear improvement by the GNFs coating is explained by self-lubrication.