Nanoscale Prediction of Graphite Surface Erosion by Highly Energetic Gas - Molecular Dynamics Simulation -

Abstract

In order to understand the fundamental essence in the erosion of graphite by hot gas molecules, in this study we investigate the mechanical properties of a single layer of graphite (e.g. graphene) and the bombardment of CO2 and H2O on graphene at high temperature by using extensive molecular dynamics (MD) simulations. The Reactive Empirical Bond Order (REBO) potential is employed to model the C-C bonds. The stress-strain curve shows that the stiffness of graphene decreases with increase in temperature. The strength of graphene at 2400 K is 60% less than the strength of graphene at 300 K. Also, we observe that the collision with CO2 and H2O provokes the bond breaking of C-C bonds in graphene at high temperature. The bombardment of gas molecules is carried out for different temperatures ranging between 300 K and 3000 K. Until 2400 K, both H2O and CO2 molecules are reflected back from the surface. However, at a critical temperature i.e., 2700 K and beyond, the bombardment of gas molecules breaks the C-C bond in the graphene. As the temperature increases, the graphene is destroyed quickly. This study shows that even the real gas molecules can induce the fracture of graphene at high temperature.