Heterogeneous blending of 2D nanoparticles as lubricant additives for enhanced tribological performance

Abstract

This work uses two-dimensional (2D) nanoparticles as lubricant additives to improve the performance of tribological systems, with a focus on minimizing wear and friction in tribo-pairs. Four types of 2D nanoparticles were chosen for investigation: Graphene (G), reduced graphene oxide (rGO), molybdenum dioxide (MoS2), and hexagonal boron nitride (hBN). The morphology and elemental composition of these nanoparticles were examined using advanced characterization methods like electron dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FESEM). A design of experiments using the Taguchi method was employed, involving four factors with three levels each, resulting in nine experiments (L9). The chosen nanoparticles were mixed with gear lubricant using magnetic stirring and ultrasonication. To ensure consistent results, a Four-ball tribometer was used, maintaining uniform surface roughness of tribo-pairs to minimize the influence of surface roughness variations. The experimental analysis demonstrated that a heterogeneous blend of nanoparticles substantially enhanced lubricant stability and tribological performance. The combination of various nanoparticles enhanced their dispersibility in the lubricant, reducing sedimentation and improving system heterogeneity. An analysis of variance (ANOVA) was performed to quantify the contributions of individual factors to the observed performance improvements. The results highlight the potential of mixed 2D nanoparticles as efficient lubricant additives, providing improved stability and enhanced wear resistance for tribological systems.