Engineering-scale superlubricity of the fingerprint-like carbon films based on high power pulsed plasma enhanced chemical vapor deposition

Abstract

It has been a great challenge to achieve superlubricity on an engineering scale. In this study, macro superlubricity was realized by fingerprint-like carbon (FP-C:H) films that were prepared by a high power pulsed plasma enhanced chemical vapor deposition technique. The macro superlubricity occurred under a wide range of test conditions, with a super low friction coefficient of 0.0016 in dry air. The unique structure and properties of the graphene layers made it capable not only to lower the shearing stress but also efficiently achieve superlubricity, following reorganization mechanics. High-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy revealed the nanostructure evolution of the wear debris. Surprisingly, a kind of multistorey graphene nanoparticles were generated in the wear debris and the humidity played an important role in the formation of these particles. Moreover, the nanostructures of these particles directly affected the friction coefficients at different humidity values. It can be demonstrated that the graphene nanoparticles were the major reason for the super lubrication of fingerprint-like carbon films, achieving incommensurate and rolling contacts. An engineering applicable method combined with the unique superlubricity properties of fingerprint-like carbon could offer an exciting opportunity to realize long-sought applications in vehicles, turbines, and manufacturing equipment.