Electrorheological Effects of Cerium-Doped TiO ₂

It is found that the doping of cerium ion into anatase TiO2 can improve the electrorheological (ER) effects of TiO2 and broaden the operational temperature range. Especially, the substitution of 7-11 mol% of the cerium dopant for Ti can obtain a relatively high shear stress, tau = 7.4 kPa (at 4 kV/mm), which is ten times larger than that of pure TiO2 ER fluid. Also, the typical Ce-doped TiO2 ER fluid shows the highest shear stress at 80 degreesC, but 40 degreesC for pure TiO2 ER fluid. The dielectric loss and dielectric constant at a low frequency of TiO2 is improved by the doping of cerium, and the temperature dependence of the dielectric properties shows an obvious difference between pure and doped TiO2 ER fluids. These can well explain the ER behaviour of doped TiO2. Furthermore, the change of rheological and dielectric properties is discussed on the basis of the lattice distortion and defects in TiO2 arising from the doping of cerium.