Preparation and electrorheological property of NaNO₃-doped Y₂O₃ material

A new class of electrorheological (ER) material using rare earth (RE=Y) oxide as the substrate, NaNO₃-doped Y₂O₃ materials, were synthesized using Na₂CO₃ and Y(NO₃)₃ as starting materials. Their ER performance, dielectric property, and crystal structure were studied. The results show that doping NaNO₃ can markedly enhance the ER activity of the Y₂O₃ material. For the suspensions of these materials in dimethyl silicone oil, a clear dependence of the shear stress on the doping degree of NaNO₃ was observed, and the optimal value of Na/Y molar ratio of 0.6 in doping degree was discovered, the relative viscosity η_r(η_E/η₀, E=4.2 kV·mm^-1) of the suspensions is nine times higher than that of pure Y₂O₃ material. The new results of the relationship between ER effect and the microstructure were obtained, which are helpful for further understanding the mechanism of ER effect and synthesizing a good ER material.