CU nanoparticles effect on the tribological properties of hydrosilicate powders as lubricant additive for steel–steel contacts

The effect of Cu nanoparticles (NPs) on the tribological behaviors of serpentine powders (SPs) suspended in diesel oil was investigated. Results show that the optimum mass ratio of Cu NPs to SPs is 7.5:92.5. With the addition of the above mixture to oil, the tribological properties can be significantly improved compared with those of the oil containing SPs alone. A more smooth and compact tribofilm has formed on the worn surface, which is responsible for the further reduced friction and wear, mainly with iron oxides, silicon oxides, species enriched in Si–O structures, graphite, organic compounds, and Cu0, Cu1+ and Cu2+ species.