The nanosized particle materials of doped-TiO_2 with Y_2O_3 were prepared by means of sol-gel technique for use in electrorheological (ER) fluids, and their crystal structures were measured by X-ray diffraction (XRD) ...The nanosized particle materials of doped-TiO_2 with Y_2O_3 were prepared by means of sol-gel technique for use in electrorheological (ER) fluids, and their crystal structures were measured by X-ray diffraction (XRD) analysis. To compare with the pure TiO_2, a distinct enhancement in the shear stress under dc electric field was found by using such materials. This can be explained by the increase of the dielectric loss and dielectric constant at low frequency. The effects of the crystal structure of the particles on the dielectric property and ER performance of materials were investigated.展开更多
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 performanc...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 ηr（ ηE/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.展开更多
The SiO_2 particle material has weak electrorheological (ER) activity. The ER performance of the SiO_2 particles can be ameliorated after adsorbing Y_2(CO_3)_3. In this paper, the effect of Y_2(CO_3)_3 and different s...The SiO_2 particle material has weak electrorheological (ER) activity. The ER performance of the SiO_2 particles can be ameliorated after adsorbing Y_2(CO_3)_3. In this paper, the effect of Y_2(CO_3)_3 and different surfactants on the ER performance of the SiO_2 particle materials is investigated. The results show that anionic or cationic surfactants maybe enhance the ER activity of SiO_2 material, and nonionic surfactants cannot when surfactants are added during the process of the SiO_2 particle preparation, only the anionic surfactant, AES, can enhance markedly the ER performance of the material. The surface area, pore volume and pore diameter of the particles were measured. The effect of Y_2(CO_3)_3 and the surfactants on the microstructure of SiO_2 materials and the relationship between ER effect and the microstructure are described.展开更多
The SiO 2 adsorbing YF 3, Y 2(CO 3) 3, Y 2(C 2O 4) 3 and YPO 4, respectively, formed four systems of particle materials: SiO 2·YF 3, SiO 2·Y 2(CO 3) 3 , SiO 2·Y 2(C 2O 4) 3 and SiO ...The SiO 2 adsorbing YF 3, Y 2(CO 3) 3, Y 2(C 2O 4) 3 and YPO 4, respectively, formed four systems of particle materials: SiO 2·YF 3, SiO 2·Y 2(CO 3) 3 , SiO 2·Y 2(C 2O 4) 3 and SiO 2·YPO 4. The electrorheological(ER) behavior of the electrorheological fluids (ERF) prepared by dispersing them in silicone oil was tested at 20 ℃ under d.c. field. The results show that the system of SiO 2·YF 3 does not display ER activity, and the ER performance of the particle materials of SiO 2·Y 2(CO 3) 3 is the best among them. The shearing stress of ERF with SiO 2·Y 2(CO 3) 3 particles is 1.644 KPa and the relative viscosity η r(=η E/η 0) is 20.3 (under field strength E=4200 V·mm -1) while the adsorbed content of Y 2(CO 3) 3 in the SiO 2 particle materials is 12.4%(mass fraction).展开更多
Pure titanium dioxide （TiO2） particle materials were prepared by hydrolyzing titanium tetrachloride （TiCl4）. The microstructures of these materials were determined by X-ray diffraction （XRD）, accelerated surface...Pure titanium dioxide （TiO2） particle materials were prepared by hydrolyzing titanium tetrachloride （TiCl4）. The microstructures of these materials were determined by X-ray diffraction （XRD）, accelerated surface area and porosimetry apparatus （BET）, and transmission electron microscopy （TEM）. The TiO2 materials obtained by calcinations under different temperatures distinctly revealed different microstructures in crystal structure type, surface area, pore size, pore volume and grain size. The relationship between the microstructure of the TiO2 materials and their electrorheological （ER） activity was investigated. Anatase titania particles have better ER performance than rutile titania particles. Amorphous TiO2 materials display higher ER activity than the crystalline titania materials. A large pore volume can be more advantageous in improving the ER effect of a particle material.展开更多
文摘The nanosized particle materials of doped-TiO_2 with Y_2O_3 were prepared by means of sol-gel technique for use in electrorheological (ER) fluids, and their crystal structures were measured by X-ray diffraction (XRD) analysis. To compare with the pure TiO_2, a distinct enhancement in the shear stress under dc electric field was found by using such materials. This can be explained by the increase of the dielectric loss and dielectric constant at low frequency. The effects of the crystal structure of the particles on the dielectric property and ER performance of materials were investigated.
文摘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 ηr（ ηE/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.
文摘The SiO_2 particle material has weak electrorheological (ER) activity. The ER performance of the SiO_2 particles can be ameliorated after adsorbing Y_2(CO_3)_3. In this paper, the effect of Y_2(CO_3)_3 and different surfactants on the ER performance of the SiO_2 particle materials is investigated. The results show that anionic or cationic surfactants maybe enhance the ER activity of SiO_2 material, and nonionic surfactants cannot when surfactants are added during the process of the SiO_2 particle preparation, only the anionic surfactant, AES, can enhance markedly the ER performance of the material. The surface area, pore volume and pore diameter of the particles were measured. The effect of Y_2(CO_3)_3 and the surfactants on the microstructure of SiO_2 materials and the relationship between ER effect and the microstructure are described.
文摘The SiO 2 adsorbing YF 3, Y 2(CO 3) 3, Y 2(C 2O 4) 3 and YPO 4, respectively, formed four systems of particle materials: SiO 2·YF 3, SiO 2·Y 2(CO 3) 3 , SiO 2·Y 2(C 2O 4) 3 and SiO 2·YPO 4. The electrorheological(ER) behavior of the electrorheological fluids (ERF) prepared by dispersing them in silicone oil was tested at 20 ℃ under d.c. field. The results show that the system of SiO 2·YF 3 does not display ER activity, and the ER performance of the particle materials of SiO 2·Y 2(CO 3) 3 is the best among them. The shearing stress of ERF with SiO 2·Y 2(CO 3) 3 particles is 1.644 KPa and the relative viscosity η r(=η E/η 0) is 20.3 (under field strength E=4200 V·mm -1) while the adsorbed content of Y 2(CO 3) 3 in the SiO 2 particle materials is 12.4%(mass fraction).
基金This project was supported by the State Key Laboratory of Vehicle Transmission（No. 51457030103 JW0201） the National Natural Science Foundation of China（Grant Nos. 20023005 and 29831010）the National Key Project for Fundamental Researh （G1998061305）.
文摘Pure titanium dioxide （TiO2） particle materials were prepared by hydrolyzing titanium tetrachloride （TiCl4）. The microstructures of these materials were determined by X-ray diffraction （XRD）, accelerated surface area and porosimetry apparatus （BET）, and transmission electron microscopy （TEM）. The TiO2 materials obtained by calcinations under different temperatures distinctly revealed different microstructures in crystal structure type, surface area, pore size, pore volume and grain size. The relationship between the microstructure of the TiO2 materials and their electrorheological （ER） activity was investigated. Anatase titania particles have better ER performance than rutile titania particles. Amorphous TiO2 materials display higher ER activity than the crystalline titania materials. A large pore volume can be more advantageous in improving the ER effect of a particle material.
