Enhancement in tribological performances of advanced microwaves synthesised MoS2 nanoparticles as nano additives in military diesel-based engine oil

The automobile industry has a strong emphasis on environmentally friendly, high-quality, long-lasting, and energy-efficient features. Features of energy efficiency.
Friction and wear are the primary causes of energy loss and mechanical failure. The application of lubricant additives is one of the most effective ways to reduce friction
and wear under boundary lubrication. The use of nanoparticles/nanomaterials as lubricant additives in lubricants such as engine oil is referred to as nanolubricants. However, nanoparticles addition in military diesel-based engine oil remains largely unexplored. In this dissertation, optimised Molybdenum disulfide (MoS2) nanoparticle was synthesised via advanced microwave synthesis method using Response Surface Methodology. The physicochemical parameters of the optimised MoS2 nanoparticles have been thoroughly studied. The nanoparticle was dispersed in SAE 20W50 military-grade diesel engine oil to formulate the nanolubricant. The tribological,
oxidation and thermal conductivity properties of the nanolubricant have been investigated using a wide range of analytical methods. FESEM images confirmed the nanosheet morphology of the MoS2 with sizes approximately 150nm-300nm and the high-resolution EDS elemental mapping has shown the uniform and homogeneous distribution of molybdenum and sulfur. The broad XRD diffraction peaks of MoS2 implied that the crystalline size is very small and confirmed that the crystal structure is pure MoS2. The FT-IR spectra reveals the required functional groups, which further confirms the formation of MoS2. The visual observation confirms that clearly indicates there was no sign of sedimentation after 21 days in the nanolubricants. The zeta potential value of the MoS2 nanolubricant with 0.05wt. %, 0.01wt. % and 0.005wt. % is to be extremely stable. The nanolubricant with 0.01 wt. % concentration of MoS2 nanoparticle showed the reduction of Coefficient of Friction (COF) and Average Wear
Scar Diameter (WSD) with 19.24 % and 19.52 % decrement compare to the base oil due to the formation of tribofilm and the mending effect. The nanolubricant with 0.05 wt.% concentration of MoS2 nanoparticle shown the enhancement of 65.68 % in Oxidation Induction Time (OIT) compare to the base oil. The synergistic effect of MoS2 nanoparticles and Zinc dialkyldithiophosphates (ZDDP) can exhibit good
oxidation stability, which enhanced the antioxidant properties. The addition of MoS2 within the base oil demonstrates an improvement in thermal conductivity with ~10 % enhancement compared to the base oil. This due to the percolation mechanism, which may increase the thermal conductivity. This study has essentially provided a thorough
understanding of a revolutionary advanced microwave synthesised MoS2 based nanolubricant. This research's integrated approach to understanding tribological, oxidation, and thermal conductivity mechanisms is expected to lead to novel strategies for building superior nanolubricants for military vehicles in the future.