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Abstract: A new class of doped electrorheological (ER) materials with rare earth (RE), TiO2 material doped with Er2O3 that belongs to the heavy rare earth oxide, was synthesized by the means of the hydrolysis and their compositions were determined by elemental analyses. The effects of the microstructure including the surface areas, pore volumes, pore size and crystal structure of the particles on the ER property of the materials were investigated by X-ray diffraction (XRD) analyses, BET surface area analyses, dielectric property and rheological measurement. The new results have shown that the microstructure, especially crystal lattice state plays an important role in influencing the dielectric property and ER property of the particle materials, which is propitious to further understanding the mechanism of ER effect and enhancing the ER activity of a material. [Copyright &y& Elsevier]

A series of nano-sized particle materials containing ZrO2 was prepared and their compositions were determined by elemental analysis and thermogravimetric analysis (TGA). The effect of particle size and crystal structure type (lattice and space group) on the ER performance of these materials was investigated by X-ray diffraction (XRD) analysis, Raman spectra, the particle size analysis and rheological measurement. Their electrorheological (ER) effects show that the ER activities of the ZrO2 materials doped with rare earth (RE=Y, La, Ce, Gd, Tb), whose grain sizes were less than that of pure ZrO2, were lower than that of pure ZrO2, which belongs to the tetragonal crystal system. The ER activity of Y2O3–ZrO2 is the strongest among all the RE-doped ZrO2 materials. The ER activity of the tetragonal phase ZrO2 is higher than that of the monoclinic phase ZrO2. [Copyright &y& Elsevier]