Rheological and Wettability Properties of Engine Oil with a Submicron Spherical Carbon Particle Lubricant Mixture

Abstract

This study examined the physical and chemical properties of engine oil with a submicron-sized carbon particle lubricant mixture. Spherical carbon particles were added to engine oil to lower the friction and wear losses. In the current study, morphological and chemical analyses of these carbon particles were performed using field emission scanning electron microscopy and energy dispersive spectroscopy. The results clearly demonstrated that these spherical particles consist of a pure carbon element. In addition, the size distribution and dispersion stability of the carbon particles in the engine oil were investigated. The results revealed that the carbon particles have a diameter in the range of 200 to 700 nm, and they maintain their suspension in the engine oil for about 240 hours without using surfactants. Rheological studies were conducted to explore the effect of carbon particles on the rheological properties of the baseline oil at different temperatures and shear rates. The viscosity measurements, at temperature ranging from 5 to 60 °C, for the baseline oil and the oil-carbon particle lubricant mixture were almost identical (less than 4 % difference). Furthermore, a wettability analysis was performed to examine the effect of carbon particles on the wetting behavior of the baseline oil on a steel substrate.