Effects of TiO2 nanoparticles and oleic acid surfactant on the rheological behavior of engine lubricant oil

In this work, we have studied the effect of titanium (IV) oxide (TiO2) nanoparticles dispersed in an engine lubricant oil on its rheological behavior. In order to prepare this nanofluid, mechanical stirrer and ultrasonic bath were used. The nanoparticles were characterized using SEM, TEM and dynamic light scanning. The rheological behavior of the system was studied by a parallel plate rheometer. Then, oleic acid, as surfactant, was used to stabilize suspensions. Also, the effect of the surfactant on the rheological behavior was studied. Three different models for rheological behavior, namely Power law, Cross and Carreau models, were considered. The Carreau model provides the best prediction of the rheological behavior for this system. (C) 2018 Published by Elsevier B.V.