A new one-step deposition approach for a low friction graphene nanoflakes coating

Since 2004, when it was first isolated, graphene has been the subject of great attention both in scientific research and in various industrial applications, thanks to its excellent physical, chemical and mechanical properties. Recently, studies have shown graphene as a new solid lubricant that improves the tribological performances of materials by lowering the coefficient of friction and increasing the wear resistance. However, the industrial-scale manufacture of graphene has been limited by the lack of a fast, inexpensive and effective coating method for large surfaces. As part of our work, we have developed a versatile RF inductively-coupled plasma technology process in which graphene nanoflakes (GNFs) were synthesized in-flight and uniformly deposited on metallic substrates. The coatings and the quality of the graphene flakes were characterized, and the macroscale tribological performance of the GNFs coating was studied using a ball-on-three-plates tribometer. The results showed that the GNFs coating reduced the coefficient of friction (COF), the loss of wear volume and the wear rate compared to an uncoated substrate. The innovative approach to GNFs-coating preparation provided in this work is expected to have diverse and important applications in the industry.