Effect of Nanodiamonds on Friction Reduction Performance in Presence of Organic and Inorganic Friction Modifiers

Abstract The strive to reduce harmful emissions from transport has resulted in an increase emphasis on minimising friction in lubricated contacting components to improve the energy efficiency of automotive engines. In this sense, it is of particular interest to investigate whether synergistic tribological performance could be achieved by combining of two or more friction modifier additives with nanoparticles especially nanodiamonds due to their distinctive tribological properties in order to minimize harmful sulphur and phosphorous concentration from lubricant formulation. This study conducts a comprehensive investigation into the tribological characteristics of lubricant formulations enriched with nanodiamonds (NDs), combined with both organic (Glycerol Monooleate, GMO) and inorganic (Molybdenum dithiocarbamate, MoDTC) friction modifiers, and a minimal quantity of an anti-wear additive (Zinc dialkyl dithio-phosphate, ZDDP) with Poly-alpha-olefin (PAO) base oil. The outcomes of tribological experiments indicate that incorporating NDs can positively influence friction and wear characteristics, depending upon their interactions with other additives present in the lubricant mixture. Analysis of wear scars using High-Resolution Transmission Electron Microscopy (HRTEM), Atomic Force Microscopy (AFM), and Raman spectroscopy reveals that employing NDs as a friction modifier with other additives is a viable strategy to lessen the use of harmful lubricant additives and enhance overall tribological efficacy.