Research of dielectric fluid dispersing barium titanate

分散钛酸钡介电液的研究

• 批准号: 03650514
• 负责人: FUJITA Toyohisa
• 金额: $ 1.41万
• 依托单位: MINING COLLEGE, AKITA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03650514/
• 关键词: Barium titanate; Dielectric fluid; Electrorheological fluid; Levitation force; viscosity

Amorphous barium titanate has been prepared by hydrolysis of titanium isopropoxide in aqueous alkaline solutions in the presence of barium ions at -320K. The dielectric constant of the barium titanate is strongly dependent on the moisture content. As the average particle size was in the range 5-10nm, the particles dispersed stably in kerosene when coated with surfactant polyoxyethylene alkyl ether acetates. A glass sphere immersed in the resulting dielectric fluid with low moisture content experienced a levitation force under the influence of an electric field gradient.The viscosity change of hydrocarbon based fluid dispersing surfactant coated about 10nm barium titanate particles was investigated under DC electric field. When the dispersed particle contained moisture, the fluid became a Bingham body under adequate DC electric field intensity at room temperature and the static yield stress was influenced extremely by the moisture percentage, volume fraction of solid particles and electric field intensity.When the dispersed particle contained no water, the fluid became easily a Bingham body at temperature between 373K and 393K under adequate DC electric field intensity. The increases of volume fraction and electric field intensity are considered to produce higher static yield stress for the practical application.

在-320K下，以异丙醇钛为原料，在钡离子存在下，在碱性水溶液中水解制备了非晶钛酸钡。钛酸钡的介电常数强烈依赖于水分含量。用表面活性剂聚氧乙烯烷基醚醋酸酯包覆后，平均粒径在5- 10 nm范围内，粒子在煤油中稳定分散。将玻璃球浸入低含水量的介电流体中，在电场梯度的作用下，玻璃球受到悬浮力的作用，研究了表面活性剂包覆约10 nm钛酸钡颗粒的烃类流体在直流电场作用下粘度的变化。当分散颗粒中含有水分时，在室温下，在适当的直流电场强度下，流体成为宾汉体，静态屈服应力受水分含量、固体颗粒体积分数和电场强度的影响很大;当分散颗粒中不含水分时，在373 ~ 393 K温度范围内，在适当的直流电场强度下，流体容易成为宾汉体。在实际应用中，体积分数和电场强度的增加被认为会产生更高的静态屈服应力。