Interfacial friction properties in diamond polishing process and its molecular dynamic analysis

The friction properties play an important role in diamond polishing, which significantly affect the interfacial contact and material removal. In this paper, the friction force and coefficient of friction (COF) during diamond polishing process were monitored under different loads and rotating speeds. The results show that the friction force and COF both increase with the load, and decrease with the rotating speed. The bearing capacity of liquid film is enhanced at large rotating speed, which leads to the decrease of friction force. According to the binomial law of friction, the increase of actual contact area caused by high load contributes to the increase of COF. Besides, it is found that the addition of H2O2 reduces the friction coefficient through surface adsorption. In order to further reveal the mechanism of friction variation at the atomic level, the friction behavior at a local area of interface between the diamond substrate and the abrasive particle in diamond polishing process was investigated by molecular dynamics (MD) method. The simulation results indicate that the interfacial bridge bonds formed between the substrate and particle under the action of load lead to the increase of friction force.