Electro-rheological Effect of Barium Titanate Particles Coated with Urea and Suspended in Methyl Silicone Oil

Barium titanate nano-powders were synthesized under defined conditions. The surface of these particles was successfully modified by coating with urea. The characteristics of these composite particles were studied by X-ray diffraction,transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy. The electro-rheological (ER) effects of these particles suspended in methyl-silicone oil were measured. The particle,methyl-silicon oil ratio was 30%-35% weight percent. The experimental results indicate that these ER particles exhibit a remarkable ER effect. The ER fluid shows Bingham characteristics and the static shearing stress increases with an increase of the electric field strength. The highest static shearing stress under a 4 MV/m electric field is 13.2 kPa at room temperature,an increase of about 8.7 kPa compared to untreated BaTiO(C2O4)2 powders.