Coordinating influence of multilayer graphene and spherical SnAgCu for improving tribological properties of a 20CrMnTi material

In order to increase the service life and operational reliability of a 20CrMnTi-steel-based gearing system, the friction and wear behavior of 20CrMnTi needs to be further improved. In this study, the sliding friction and wear properties of 20CrMnTi, 20CrMnTi-1.50 wt% graphene (20-Gr), 20CrMnTi-15.00 wt% SnAgCu (20-Sn), and 20CrMnTi-15.00 wt% SnAgCu-1.50 wt% graphene (20-Gr-Sn) were examined on a ball-on-disk tribometer. The friction and wear properties at 0–85 min of 20-Gr-Sn were significantly better compared to those of 20CrMnTi, 20-Gr, and 20-Sn. Metallic oxides appeared on the smooth wear scar of 20-Gr-Sn, which were tightly combined with the 20CrMnTi-based material. This caused a lubrication film with low hardness (approximately 1.25 GPa) to form on the grain-refined layer with high hardness (approximately 5.92 GPa). Graphene and SnAgCu in the lubrication film exhibited excellent coordinating lubrication to result in a low friction coefficient and lower wear rate. The obtained results can provide a good reference for increasing the service life of 20CrMnTi-steel-based gear systems.