Preparation and Electrorheological Property of Y4O(OH)9(NO3)-NH4NO3 Materials

The new electrorheological (ER) material, a particle material composed of Y4O(OH)9(NO3) and NH4NO3, was obtained. They display better ER performance. The shear stress of the suspension of Y4O(OH)9(NO3) (NH4NO3)2.8 material in dimethyl silicone oil reaches 1469 Pa at an electric field strength (E) of 4.2 kV. mm−1 and the shear rate (γ) of 150s−1. The relative shear stress, τE/τ0 (τE and τ0 are the shear stresses at E = 4.2 and O kV-mm−1, respectively), is up to 29, which is 19 times that of pure Y2O3 material. The dielectric and conductive property of the materials play important roles in the modification of the ER effect of the particle materials. The researches on these new ER materials are very useful for obtaining a better understanding on the mechanism of the ER effect and finding an ideal ER material.