Investigation of lubricant depletion under a continuous heat source using molecular dynamics simulation

Abstract

In this study, a model for investigating lubricant depletion in heat assisted magnetic recording slider/disk system was developed using molecular dynamics simulation. The effects of relative velocity VR between continuous heat source and disk, lubricant molecular weight and interaction strength between lubricant end groups and functional sites on diamond like carbon (DLC) surface on lubricant degradation and depletion were investigated. The simulation results showed that lubricant depletion depth decreases with increasing relative velocity VR. A comparison of lubricant depletion using models with and without bond breakage to simulate lubricant degradation was made. We found that the main reason for lubricant depletion is lubricant desorption rather than lubricant degradation. In addition, an increased lubricant molecular weight could reduce lubricant depletion. Lubricant depletion can be significantly reduced by simultaneously increasing the ratio of the functional groups on the DLC surface along with the molecular weight and the functional end group bonding strength.