In this paper, the effect of different parameters on Fe3O4/water nanofluid preparation characteristics is investigated experimentally. Two criteria, stability and magnetism, are employed to characterize prepared ferrofluids. Dynamic light scattering methods (DLS) distribution and transmission electron microscopy (TEM) images are applied in nanoparticle size investigation. Two-step preparation method is used to prepare the ferrofluid samples. Zeta potential and vibrating sample magnetometer (VSM) methods are used to study the stability and magnetism characteristics of prepared ferrofluid samples, respectively. The effect of six parameters (surfactant material, surfactant mass, heater stirring speed, heater stirring time, pH, initial sonication time and final sonication time) with three levels and one parameter (surfactant material) with six levels on the stability and magnetization is considered. The Taguchi method is applied in design of experiments, and 18 samples are prepared. The results show that the effective parameters on the stability of the prepared ferrofluid as their importance are: surfactant material, pH number, initial sonication time, surfactant mass, final sonication time, heater stirring speed and heater stirring time, respectively. According to magnetization viewpoint, the order of importance for effective parameters is: surfactant material, surfactant mass, pH number, final sonication time, heater stirring time, initial sonication time and heater stirring speed, respectively.

Keywords