Abstract
Lubricant oils in cars engines are essential components for reducing friction and fuel consumption. The lubrication process can be improved by including effective additives. Carbon nanostructures have been recognized as excellent additives in lubricant oils. Amongst them carbon nanotubes (CNTs) produced from carbon rich fly ash, are found to have excellent tribological properties in the sunflower base oil. In this work, these CNTs along with other micro and nanostructures produced from carbon rich fly ash are tested as lubricant additives in the 150SN base oil. The impregnated oils with these additives are evaluated to reduce the friction between two metallic surfaces using the ball-on-disk tribometer. The obtained results showed that CNTs of fly ash have significantly reduced the frictional coefficient by around 25% at a concentration of 0.1wt%. This result is much better than that of the other fly ash micro and nanostructures produced by sonication and ball milling techniques. It is also compared with that of a commercial multiwall CNTs and is found to be superior. The friction coefficient values are investigated as a function of load and temperature. Moreover, the rheological behavior is also studied for the pure and 0.1wt% CNTs-impregnated oil. No significant changes are observed in the viscosity of the impregnated oil. The present CNTs of carbon rich fly ash have been proved to be effective additives for the 150SN lubricant oil, and might be useful for variety of lubricants.