In this article, synthesis and rheological behavior of Fe2O3 magnetic nanoparticles ferrofluids in paraffin base as well as their magnetoviscos effects have been investigated. In order to prepare the ferrofluids, ball mill and ultrasonic bath were used. Then rheological behavior of the system was studied using a standard rotating rheometer. Oleic acid was used to stabilize ferrofluids. Also the effect of magnetic field on the fluid was studied. It is shown that using magnetic field will cause noticeable increase in viscosity at constant shear rate. This increase in viscosity, however, is limited to a specific rate of magnetic field. Also, a novel correlation for predicting temperature dependency of fluid has been presented.
