Molecular Dynamics Study of Nano-Tribological Properties of Silicon Nitride Films

Silicon nitride films were attracting extensive research interest in the past few decades as hard disk protective coating, especially the beta-silicon nitride (β-Si3N4) films and amorphous silicon nitride (SiNx) films, which have high hardness, chemical durability and low friction coefficient properties against wear, corrosion and reducing the friction resistance, respectively. Considerable efforts have been made in studying silicon nitride. However, it’s difficult to determine its nano-tribological properties experimentally since the results were affected by a lot of contact and environment conditions.

The molecular dynamics (MD) simulation method is employed in this work. A rigid diamond sphere modeled as a spherical tip are sliding over a layered silicon nitride film substrate, respectively, to investigate the tribological properties of silicon nitride films. The effect of the relative sliding velocity and sliding direction, the normal force and the thickness of crystalline silicon nitride films on the friction coefficient of silicon nitride films were investigated.