Effect of normal loads and mating pairs on the tribological properties of diamond-like carbon film

Abstract

The influence of normal loads and mating pairs on the tribological properties of diamond-like carbon (DLC) film was investigated using atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman characterizations. The friction and wear behaviors of DLC film are not only related to the friction pairs but also related to the normal loads. The friction coefficient and wear rate of DLC film are smaller with the increase of load, but the wear degree of DLC film is more serious with the increase of hardness of the friction pair. Raman analysis indicates that the structural evolution of DLC film should have a limited contribution on the different friction behaviors of DLC film against ZrO2, bearing steel and SiC balls. The results of TEM and Raman characterizations further show that the key factor determining the low friction of DLC film is the graphitization degree of the transfer layer rather than the formation continuity and compactness of the transfer layer. The results further deepen our understanding of the related mechanisms between DLC films and friction pairs under different normal loads as guidance for the application of DLC films in future industrial fields.