Study of the normal force and velocity influence on the fused silica scratching mechanisms with α-alumina grit at atomic scale via Reaxff reactive molecular dynamic simulations

Fused silica is an optical glass employed in several industries, which is grinded and polished to obtain ultra-smooth surface by using α-alumina abrasives. Scratch testing is a powerful technique to assess the process conditions that provoke the process induced damages. Applied normal load and velocity on abrasive grain are main influential parameters under consideration. Previously studies on scratching of this glass are mainly focused on mechanical mechanisms, its chemical mechanisms have not been well analysed. In this paper, the Reaxff molecular dynamic simulation is used to study both mechanical and chemical mechanisms in scratching processes under various velocities and forces. The results reveal three distinct phenomena (penetration, penetration with dragging and dragging) in scratching processes. Under the conditions of lower force and velocity, the scratching depth presented small, and the temperature and potential energy were stable during scratching. The chemical interaction between the grain and glass appears as adhesion.