Preparation and Tribological Properties of Graphene Lubricant Additives for Low-Sulfur Fuel by Dielectric Barrier Discharge Plasma-Assisted Ball Milling

Abstract

Poor lubrication performance of low-sulfur fuel leads to increased wear of diesel engine components. In order to improve the lubrication properties of low-sulfur fuel, we successfully prepared graphene lubricant additives by dielectric barrier discharge plasma-assisted ball milling. The tribological properties of graphene lubricant additives in two types of 0# diesel oils with different sulfur content were evaluated by high-frequency reciprocating rig (HFRR). The results indicated that the expanded graphite was exfoliated and refined into graphene sheets with nine layers by the synergistic effect of the heat explosive effect of the discharge plasma, the impact of mechanical milling function, and the cavitation effect of 0# diesel oil. The organic functional groups of 0# diesel oil were successfully grafted on the surface of graphene sheets. The addition of 0.03 wt % graphene resulted in 20% reduction in the friction coefficient (COF) and 28% reduction in wear scar diameter (WSD) compared to pure 0# diesel oil with a sulfur content of 310 mg/kg. The addition of 0.03 wt % graphene resulted in 24% reduction in the friction coefficient (COF) and 30% reduction in wear scar diameter (WSD) compared to pure 0# diesel oil with a sulfur content of 1.1 mg/kg. The formation of graphene tribofilm on rubbing surfaces improved the lubrication properties of low-sulfur fuel.

Taguchi optimization of process parameters used for improving tribological behaviour of graphene nanoparticle dispersed nanolubricant

“…Our findings suggest that 0.05 wt% as the optimal graphene nanoparticle concentration to be dispersed in base POE oil. This finding is, to some extent, in line with the findings of [40], which revealed that an addition of 0.03% graphene nanoparticles in diesel oil reduces COF by 20%. Similarly, another study [41,42] concluded that 0.05 wt% graphene nanoparticles significantly results in the reduction of COF.…”

Development of Doped Carbon Quantum Dot-Based Nanomaterials for Lubricant Additive Applications

“…Frequently used nanoscale lubricant additives are metals, metal oxides, metal sulfides, metal borates, polymers, and carbon-based nanomaterials [18][19][20]. However, nanoscale carbon materials have become increasingly popular in the lubricant additive community due to their ecologically approachable nature, exceptional self-lubricating behavior, good chemical and high thermal stability and outstanding mechanical properties with respect to bulk carbon materials [21][22][23]. As shown in Figure 1, the most commonly used carbon-based lubricant additives are fullerene, graphene, nano-graphite, carbon nanotubes, and other bulk carbon materials.…”