A Reactive Force Field Study on the Interaction of Lubricant with Diamond-Like Carbon Structures

Abstract

We studied the degradation of a perfluoropolyether lubricant, i.e., D4OH, in the presence of different components present in hard disks including diamond-like carbon (DLC), using ReaxFF reactive force field based molecular dynamics simulations. To generate the DLC structure, a carbon-diamond structure was melted in an Ar-filled head space box at 7500 K, and was slowly cooled down to 3000 K. Then, a constant pressure (NPT) simulation was performed to adjust the sample volume and reduce the internal stress. Similarly, for growth of functionalized DLC, ethylene molecules were used as the carbon source and they were pyrolyzed in the presence of Ar atoms to make H-functionalized DLC (DLC:H). This DLC:H structure was subsequently heated in the presence of nitrogen molecules to make H/N functionalized DLC (DLC:H:N). The results indicate that, by controlling number of Ar atoms and N2 molecules, it is possible to achieve the experimental H/N/C composition and sp2/sp3 ratio composition targets. Final DLC and DLC:H:...