Synthesis and rheological properties of water-based Fe3O4 magnetic fluid

This paper first prepared a water-based magnetic fluid using a chemical co-precipitation method and conducted a detailed characterization and calculation of its important magnetization properties. Key parameters for analyzing the influence mechanism on the rheological properties of the water-based magnetic fluid were obtained. Subsequently, the impact of different magnetic field and shear rates on the magnetoviscous effect, shear-thinning behavior, and yield stress of the water-based magnetic fluid was studied through steady rotation measurements. The results showed a positive correlation between viscosity, shear stress, and yield stress with the magnetic field. Additionally, we also provide theoretical prediction formulas for the magnetoviscous effect based on the influence of microstructures formed by solid-phase magnetic particles in the magnetic field. The dimensionless Mason number was used to establish the scaling law relationship between viscosity measurements and theoretical values, with results showing good agreement between measured and theoretical values. The Herschel–Bulkley model and the Casson model were employed to obtain the dynamic yield stress values of the sample, and a quadratic linear increase relationship between yield stress and magnetic field was derived. These research findings provide important references for a deeper understanding of the physical and chemical properties of water-based magnetic fluid and for optimizing its application.