Modified Oxide-based Preparation And Properties Of Er Fluid

Electrorheological Fluid (ERF) is a suspension that consists of high dielectric constant particles and insulating oil of low dielectric constant. When in electric field, ERF can change from liquid to something similar to solid, with its viscosity's increasing. This inversion is instantaneous and reversible. The character of the particle is the main factor that effects the performance of ERF .The author prepared some inorganic particles that can be used in ERF, based on the idea that designing the material from it's physical and chemical character .The following are the result:1. The ER fluids composed of RE (Y, La, Ce)-doped BaTiO3 were prepared by Sol-gel method. Doping of Y, La, Ce into BaTiO3 is found to improve ER activity of BaTiO3. Among the three rare earth elements, Y is the best one that whose doping can improve the activity of BaTiO3 ERF best. Every RE element should be used around a certain amount. More than this, the ER effect will get worse, because of the RE element's moving out of the crystal lattice of BaTiO3. So we can get a conclusion: RE element's doping can change the lattice of BaTiO3, which induces the increasing of the dielectric constant of BaTiO3 and improves the activity of BaTiO3 ERF.2. BaTiO3 particles were prepared using the sol-gel method. BaTiO3 ERF was made ofmixing the BaTiO3 particles with the silicate oil. Microwave's passing through the BaTiO3 ERF can give the following result. When the direction of microwave parallels with the electric field, the transmittance of the microwaves decreases with the intensity of the electric field. And when the direction of microwave plumbs the electric field, there will exist a critical concentration. Below it, the transmittance of the microwave changes as the former. Above the critical concentration, the transmittance of the microwave changes the other way round.3. Four small molecule organic's acting with a compound contanining Ba,Ti,Oelements that was prepared in the solution under low temperature can obtain four composites. The activity of them can be explained from their dielectric character. The author also studied the temperature effect of the four ERF.4. The porous HMS particle was prepared. DMS can act with HMS in the pores.DMS-HMS particles performance better ER activity than that of pure HMS particles. It should owe to the dielectric difference between the HMS and DMS-HMS particles.5. The anatase TiO2 and Ce-doped rutile TiO2 was prepared under low temperature.The TiO2-MMT particle was also made use the direct incorparating method. TheTiO2-MMT particle shows better ER activity than pure MMT particle. Nay, TiO2-MMT particle shows good temperature effect than MMT. The shear stress of former can increase with the temperature while the latter decreases.