Abstract: N-glucose ethylenediamine triacetic acid (GED3A) was used to modify the surface of carbonyl iron (CI) particles for preparing composite magnetic particles (CMPs) and aqueous magnetorheologic (MR) fluids. The properties of the obtained CMPs, including morphology, magnetic property, and anti-oxidation ability, were characterized by scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The magnetorheologic properties of aqueous MR fluids were measured using a commercial rheometer equipped with a magnetic field supplier and controller. Meanwhile, the dispersion stability and the anti-oxidation ability of the prepared aqueous MR fluids were also analyzed via stability test, air oxidation test, and acid corrosion test, respectively. The results are shown in below. (i) The CMPs possess better soft magnetic properties (magnetic saturation (Ms ): 182.2 emu·g-1, coercivity (Hc ): 4.17 Oe, remanence (Mr): 0.1944 emu·g-1. (ii) Compared with the aqueous MR fluid based on CI particles, the dispersion stability, anti-oxidation ability, and magnetorheological effect of the aqueous MR fluid based on the CMPs were substantially improved. The sedimentation ratio dropped by about 24.4%; and in the range of 0.02-0.10 mol·L-1 of acids, the anti-oxidation ability increased by 92.6%-95.7%for HCl, and 86.1%-93.8%for HNO3.

Key words: Composite magnetic particles, Aqueous magnetorheological fluids, Anti-oxidation ability, Dispersion stability