Nanoparticles exhibit diverse effects when added as additives to oily medium, enhancing tribological properties and surface characteristics. Studies have shown that many oxide ceramic nanoparticles improve friction and wear, while mixtures also demonstrate favorable tribological properties. This study explores the tribological effect of an yttria–silica (Y2O3, SiO2) nanoparticle mixture in a Group III base oil medium. The results reveal that the yttria–silica mixture significantly reduces friction (−8–17%), mean wear scar diameter (−32%), and wear volume (−94%), while increasing load-bearing capacity (+114%) by creating a durable boundary layer. Observations from scanning electron microscopy revealed the original surface is protected. EDX analyses highlight the boundary layer’s elemental composition, which is high in yttrium, silicon, and oxygen and found in higher areas. XRD analysis could not detect the yttria nanoparticle additive within the boundary layer, suggesting that it fragmented due to sliding stress, resulting in an amorphous structure for the new boundary layer. TEM imaging confirmed that the boundary layer thickness is 40–45 nm. These findings demonstrate significant potential for industrial applications in developing advanced, high-performance lubricants for demanding mechanical systems.

This article investigates the impact of copper(II) oxide (CuO) and titanium dioxide (TiO2) nanoparticles in Group III base oil with 8 wt% Komad 323 dispersant. Nanoparticles underwent ethyl oleate surface modification. Tribological properties were assessed using a linear oscillating tribometer, continuously monitoring static friction. Friction integral values were derived from extensive data acquisition. Wear analysis employed digital optical and confocal microscopy, complemented by scanning electron microscopy for wear-type characterization and energy-dispersive X-ray spectroscopy for additive quantification in the wear track. Results indicate CuO nanoparticles' poor compatibility with Komad 323, resulting in increased friction (2-13%) and substantial wear reduction (39-50%) at low CuO concentrations (≤0.3 wt%). Higher concentrations (≥0.4 wt%) reduced friction (21-35%) but led to surface fatigue and increased wear rates. Elemental composition analysis of the wear track revealed that the surface contains 1.43-3.17 norm.wt% copper. Conversely, TiO2 in synergy with the dispersant, formed a boundary layer, exhibiting lower friction by 11-14%. TiO2 formed a high wear resistance boundary layer at titanium concentrations of 0.33-0.39 norm.wt%, which resulted in 44% wear volume reduction. Applying both nanoparticles reduced the wear scar diameter of the test specimens by 3-12%.

This study examines oil samples with zirconium dioxide (ZrO2) nanoparticles in Group III base oil at different temperatures, revealing the effects of temperature and concentration on the tribological system. The samples contain 0.1% and 1% ZrO2 nanoparticles, tested at 40–120 °C. The friction results showed that the nanoparticles increase the friction absolute integral values at all tested temperatures; however, static friction can be improved by 3–13%. The study demonstrates the wear-resistant effect of ZrO2 nanoparticles. Significant wear reduction can be achieved even at low concentrations; wear volume can be reduced by 21–87% depending on the nanoparticle concentration and operating temperature. Scanning electron microscopy with EDX helped to identify wear types, the processes occurring on the surfaces, and the percentage of nanoparticles on the surface.