The technology of nanofluids as a promising future tool is believed to meet the current requirements of a green environment that aim to reduce the irreversible losses of fluid machinery. This is to balance the incrementalism demands of efficient energy production and minimize its drawbacks on the environment. To bridge this gap, designing machinery with low friction losses is the primary requirement for a potential reduction in energy loss over the upcoming 15 years. In internal combustion engines, the presence of mechanical friction through engine constituents accounts for a major portion of power losses. Controlling tribological performance for engine lubricants has a major role in limiting these losses. This can be achieved by diminishing the boundary friction coefficient, which is considered a crucial factor for efficiency improvement. Over the last few years, attention to the employment of Nanoparticles as an environment-friendly lubricant additive had steadily expanded due to the apparent moderation in wear properties of Nanoparticles containing lubricants (so-called Nano lubricants).In this study, the tribological properties of custom formulated and stabilized Nano lubricant that holds spherical zinc oxide (ZnO) nanoparticles suspended in 20W-50 mineral base lubricant using Oleic Acid (OA) as a surfactant are investigated.Three different concentrations of Nano lubricants with 0.2, 0.5, 1 % wt were analyzed through ASTM G99 pin-on-disc tribometer standardized test. Investigations were conducted under numerous conditions of the load from 147 to 392 N and sliding speed from 0.5 to 1.5 m/s with boundary /mixed lubrication regimes. The generated friction and wear analyses confirm a consolidation of tribological properties with a reduction in friction coefficient and wear rate, compared with base lubricant. Analysis of worn surfaces using SEM/EDX (Scanning electron microscopy/ Energy-dispersive X-ray spectroscopy) was &nbsp;&nbsp;conducted. Combined evidences were proposed form the analysis of worn surfaces suggested that ZnO Nanoparticles exhibit an integrated effect of two phenomenal lubrication mechanisms of Tribo-sintering and Nano ball bearing (third body) for the anti-wear and antifriction properties.Additionally, stabilization analysis of the suspended ZnO Nanoparticles was performed through FTIR and sedimentation analyses. Results revealed that when the ZnO Nanoparticles concentration was small (e.g. 0.2 % wt), Nanoparticles would not be sufficient to effectively exhibit the third body neither the Tribo-sintering lubrication mechanisms. Conversely, when the ZnO concentration was raised up to 1 %, aggregation was observed as well as the aggravation of friction and dispersing results. An optimal concentration of 0.5 % wt ZnO &nbsp;is suggested for a prime tribological performance of Nano lubricant based on the conducted investigations.

Study on Tribological Behaviour of ZnO Nano Additives Suspended in SAE 20W-50 Engine Oil on Tribological Behaviour of ZnO Nano Additives Suspended in SAE 20W-50 Engine Lubricant

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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