Enhanced tribological properties of diesel engine oil with Nano-Lanthanum hydroxide/reduced graphene oxide composites

Nano-lanthanum hydroxide/reduced graphene oxide (nano-La(OH) 3 /RGO) composites were successfully prepared as anti-wear additives for diesel engine oil. Response surface methodology was adopted to explore the influences of temperature, contact pressure, and composite concentration on the tribological properties of diesel engine oil. The anti-wear mechanism of nano-La(OH) 3 /RGO composites was simultaneously studied by comparing with the tribological behavior of graphene oxide and nano-La(OH) 3 pure particles. Results indicate that nano-La(OH) 3 /RGO composites can remarkably improve the anti-wear performance of diesel engine oil under boundary lubrication conditions. In particular, the anti-wear performance of diesel engine oil increased by 44% after adding 0.1 wt% composites at a temperature of 80 °C and a contact pressure of 1.62 GPa. The synergistic anti-wear mechanism of graphene and lanthanum oxide was proposed on the basis of worn surface characterization .