稀土改性二氧化钛电流变液的性能

PROPERTIES OF TITANIA ELECTRORHEOLOGICAL FLUIDS MODIFIED BY RARE EARTH

用溶胶－凝胶法制备了稀土元素改性的二氧化钛微粉，利用 ＤＳＣ、ＴＧ、ＸＲＤ等表征微粉，测试了微粉的介电性能，用微粉和甲基硅油配制了无水电流变液．流变学测量结果表明掺杂改性后的二氧化钛电流变液具有比在相同制备条件下所得纯二氧化钛配制电流变液强得多的电流变效应，典型的颗粒／硅油体积比为３５％的电流变液，在２５℃、直流３ｋＶ／ｍｍ、剪切速率为１．４４１ｓ^（－１）条件下的剪切强度可达１．７ｋＰａ，电流密度小于１０μＡ／ｃｍ~２，零场粘度为３～ＳＰａ·ｓ．稀土的掺杂量对电流变效应影响非常明显，存在一个稀土元素的最佳含量范围讨论了电流变液的剪切应力与电场强度、剪切速率的关系。

The water-free Electrorheological fluids (ERF), made of modified titania (TiO2) doped with rare earth (RE), were synthesized by means of sol-gel technique. The behavior of the suspensions of modified titania particles in silicone with a 35% by volume were investigated under DC electric fields. Much stronger ER effect in modified titania ERF than that of pure titania/silicone oil, which was synthesized by the same mean, is observed. In the electric fields of 3kV/mm, when shear rate of 1.441 s-1 were applied to the ERF at 25 ℃, the shear stress can be 1.7 kPa, while the current density was only 10μA/cm2 and the zero viscosity of the ERF was 3-5 Pa.s. RE/Ti mole ratio has an important influence on the ER effects. The thermal characteristic of modified titania was investigated by DSC and TG, the crystal structure of pure and doped titania particles were investigated by XRD. Relationships between shear stress and electric fields. between shear stress and shear rate were discussed.