Synthesis and properties of magnetic fluids produced on the basis of magnetite particles

Resumo

Magnetic fluids based on magnetite synthesized by the chemical condensation method at temperatures of 25, 40, 60, and 80°C were obtained and studied. Magnetite particles were examined by X-ray phase and X-ray fluorescence analyses and electron microscopy. The average size of the coherent scattering region of magnetite particles was 13–17 nm, depending on the synthesis temperature. Magnetic fluids were synthesized from magnetite particles obtained at 25 and 80°C, with water and octane serving as carrier fluids. The NMR method was used to determine the saturation magnetization and average magnetic moment of the particles: for water-based magnetic fluids, 2100 A m^–1 and 5.7 × 10^–19 A m² at magnetite particle synthesis temperature of 25°C and 3670 A m^–1 and 4.6 × 10^–19 A m² at magnetite particle synthesis temperature of 80°C; for octane-based magnetic fluids, 2250 A m^–1 and 4.1 × 10^–19 A m² at magnetite particle synthesis temperature of 25°C.