<i>In Situ</i> Synthesis of Graphene Nitride Nanolayers on Glycerol-Lubricated Si₃N₄ for Superlubricity Applications

The increasing demand for sustainable tribology has accelerated the development of environmentally friendly lubrication solutions such as water or water-related lubricants. Earlier works have reported on water-lubricated sliding silicon nitride (Si3N4) at high speeds, which can result in a superlow friction (μ < 0.01) owing to formation hydrodynamic films hydrophilic surface layers. Here, combined boundary-lubrication experiments low speeds and atomistic simulations reveal an alternative superlubricity mechanism glycerol-lubricated Si3N4. X-ray photoelectron time-of-flight secondary ion mass spectrometry performed inside outside wear track well high-resolution spectroscopy used lubricant strongly suggest that sub-nanometer-thick graphene layers form very top In accompanying simulations, glycerol molecules undergo tribochemical decomposition react with surface-bound nitrogen atoms carbon nitrides. Further shearing promotes 2D nitrides passivate ceramic surfaces induce under boundary lubrication. Thus, Si3N4 potential use green enabled by situ synthesis disordered species.