Hong Yan Guo

Urea Effect on Strong Electrorheological Response of Novel Core-Shell Nanoparticles

Electrorheological (ER) fluids are regarded as smart materials with potential for application in various industries because of the controllable viscosity, the reversibly and fast response. In this paper, core-shell structured Ni/Ti/Urea nanoparticles, as an ER material, were prepared by a sol-gel method. TEM, XRD and FT-IR spectra demonstrated that the Ni nanoparticles have been homogeneously coated with a 2 nm thick layer of TiO2 containing polar groups. The polar groups were caused by the introduction of urea. The ER effect of the fluids of Ni/Ti/Urea particles in silicone oil was investigated under a DC electric field. It is found that the ER fluids of the urea-doped Ni/TiO2/Urea particles have a high ER activity, which is 10 times that of the particles containing no urea. The polar groups in the particles are the intrinsic reasons for the enhancement of electrorheological effect.

Effect of Particles Size on the Properties of Nano Core-Shell Ni/TiO2 EMR Fluid

By means of mechanical properties test， the relationship among particle size，electric field，magnetic field ,electromagnetic field and shear ratio on the Ni/TiO2/Urea core-shell particles electrorheological fluid properties analyses. It is found that with increasing particle size， the property of electrorheological fluid decreased, and with increasing shear ratio the property of electrorheological fluid increased for same composition ER. At same time, the smaller of particle size, the higher of ER properties, but there is a critical value for shear ratio, the properties of ER is near value for same composition ER fluid. In magnetic field, the properties of ER showed a contrary result, the smaller of particle size, the lower of ER properties，and electromagnetic field make the properties increase.

Research on the Properties and Making Methold of Multi Alcohol Modification Particles ER Fluid

This paper emphasis has researched the microstructure, mechanics properties of multi alcohol modification particles ER fluid,compared the difference of microstructure and properties modification by multi alcohol, it has grasped the law of microstructure and mechanics properties of multi alcohol-Ti-O particles ER fluid.

Effect of Making Technology on Properties of Ni/TiO2/PAn Particles ER Fluid

This paper emphasis has researched the effect of particles scattering, surrounding thickness, heat treatment temperature and etc on microstructure, mechanics properties and macrostructure under different electric field of Ni/TiO2, Ni/TiO2/PAn Particles ER fluid, It is found that particles scattering, surrounding thickness, heat treatment temperature have major effect on shear stress and chain of particles.

Rheology Properties of Ni/TiO2/SDBS EMR Fluids

By means of mechanical properties test，the relationship among shear ratio, concentration and electric field, magnetic field, electromagnetic field on the Ni/TiO2/SDBS EMR fluid properties have been analyzed. It had found that with increasing shear ratio，the shear stress of Ni/TiO2/SDBS EMR fluid increased for same composition, but there is a critical value. With increasing concentration，the property of EMR fluid increased for same shear ratio. Coupling electromagnetic field makes the properties improve.

Effect of Urea Content on Properties and Microstructure of Ni/TiO2 Group Particles ER Fluid

This paper emphasis have researched the effect of Ni/TiO2 group particles modifier with Urea by properties and microstructure，it has showed that ER activity of the particles were closely associated with urea content. When the mass ratio of urea/Ti is 30%, The microstructure observation of the ER fluids under DC electric field showed that the particles aggregated to form thicker and dense column structure when the mass ratio of Urea/Ti is 30%, while the column structure were broken when excessive urea (>30%) was added. A thin and loose column structure was formed in non-urea added ER fluid.

Electrorheological Properties of Ni-Group Nano Particles and Multilayer Compound Polar Molecule Modify

This paper emphasis has researched the ER properties of Ni group core-shell nano particles modifier with Urea，SDBS and other polar molecule，analysis the relationship among ER properties and polar molecule type ，compound modifier under different electric field or magnetic field. It is found that the shear stress increasing with adding polar molecule, compound polar molecule modify can marked advance the properties of Ni group core-shell particles ER fluid.

Properties and Structure of Ni/TiO2/Polar Molecule Core-Shell Particles Electrorheological Fluid

By means of mechanical properties test and structure observation， the relationship among electric field strength, polar molecule type, content on the Ni/TiO2 group electrorheological fluid properties have been analyzed. It is found that with increasing electric field strength，the properties of electrorheological fluid increased for same composition ER fluid. Different type polar molecules have distinct effect. For same particle，with increasing polar molecule content，the property is increased, but there is a critical value . Polar molecule make particles chain of electrorheological fluid become strong，coarse and interweaved each other.

Effect of Particles Concentration on the Properties and Microstructure of Ni/TiO2 Group EMR

By means of mechanical properties test and microstructure observation,the relationship between mechanical properties ,microstructure graph of core-shell Ni/TiO2 group particles concentration of EMR and different electric field, magnetic field or electric-magnetic field have been researched. It is found that with increasing of particles concentration, the properties are increased. But there is a critical range value, too high or too low particles concentrations are harmful to properties and microstructure. The best particles concentration of Ni/TiO2 particles is about 30%. In the same field with increasing concentration, particles chain of electrorheological fluid under certain electric field become more strong,brawnier and interweaved each other.

Research on the Properties of Nano Core-Shell Ni/TiO2/Urea EMR Fluid

In the present paper, mechanical properties test and morphology observation，the effect among electric field, magnetic field and electromagnetic field, shear ratio on the Ni/TiO2/Urea core-shell particles electrorheological fluid properties were studied. It is found that with increasing electric field, magnetic field and shear ratio in the same composition electrorheological fluid, the property of electrorheological fluid can be increased. However, there is a critical value for shear ratio. When shear ratio is larger than 20s-1, the property of ER is nearly certain value for same composition ER fluid. Electromagnetic field reciprocal effect can increase the properties of ER fluid, and make the particles chain become thicker and interweaved each other.