Molecular dynamics study on the mechanism of AFM-based nanoscratching process with water-layer lubrication

Abstract

The atomic force microscopy (AFM) based direct nanoscratching has been thoroughly studied but the mechanism of nanoscratching with water-layer lubrication is yet to be well understood. In current study, three-dimensional molecular dynamics (MD) simulations are conducted to evaluate the effects of the water-layer lubrication on the AFM-based nanoscratching process on monocrystalline copper. Comparisons of workpiece deformation, scratching forces, and friction coefficients are made between the water-lubricated and dry scratching under various thickness of water layer, scratching depth and scratching velocity. Simulation results reveal that the water layer has positive impact on the surface quality and significant influence on the scratching forces (normal forces and tangential forces). The friction coefficients of the tip in water-lubricated nanoscratching are significantly bigger than those in the dry process. Our simulation results shed lights on a promising AFM-based nanofabrication method, which can assist to get nanoscale surface morphologies with higher quality than traditional approaches.