Effect of Surface-Modified Graphene Addition on In Situ Synthesized Iron-Based Friction Materials

In this study, the iron-based friction material was prepared directly from vanadium-bearing titanomagnetite concentrates via in situ selective carbothermal reactions and vacuum sintering. To further enhance the comprehensive properties of iron-based friction materials, graphene was employed as a reinforcing phase. Meanwhile, to fully utilize graphene’s enhancing potential, copper-coated graphene was fabricated by modifying the graphene surface. Subsequently, a comparison study was carried out to examine the effects of both unmodified and copper-coated graphene on iron-based friction materials. The results revealed that the inclusion of unmodified and copper-coated graphene greatly decreased the wear rate and friction coefficient of iron-based friction materials while also increasing their hardness, especially those containing 0.8 wt.% graphene. Samples with 0.8 wt.% unmodified and copper-coated graphene showed, in comparison to the sample without graphene, a 12 and 29% increase in hardness, a 44 and 69% decrease in wear rate, and a 19 and 27% decrease in friction coefficient. Furthermore, the iron-based friction materials with unmodified and copper-coated graphene exhibited milder abrasive, adhesive, and oxidative wear than the iron-based friction materials lacking graphene. Moreover, the iron-based friction materials with copper-coated graphene demonstrated superior properties compared to those containing graphene.