Effect of Different pH on Characterization of Oil-Based Magnetic Fluid

Abstract

In this paper, the oil-based magnetic fluid was prepared by chemical co-precipitation method and sodium oleate was the surfactant. The effect of different pH on the characterization of magnetic fluid was studied. The characterization was detected by Fourier Transform Infrared spectroscopy (FT-IR), Transmission Electron Microscope (TEM) and Vibrating Sample Magnetometer (VSM). The results show that the nanoparticles were coated successfully by sodium oleate at pH=5. And the saturation magnetization of Fe3O4 magnetic nanoparticles is 58.0 emu/g, the saturation magnetization of magnetic fluid prepared is 20.2 emu/g, and the Fe3O4 particles are dispersed well. Although the Fe3O4 magnetic particles coated by sodium oleate at pH = 10.5 has a higher saturation magnetization (67.8 emu/g), but the magnetic fluid is less stable and has an obvious settlement phenomenon.