低温液压油基纳米磁流体的制备与流变特性研究  

Preparation and rheological properties of low-temperature hydraulic oil-based magnetic nanofluids

作　　者：朱启晨 吴张永[1] 蒋佳骏 李翔 莫子勇[1] ZHU Qicheng;WU Zhangyong;JIANG Jiajun;LI Xiang;MO Ziyong(Faculty of Mechanical and Electrical Engineering,Kunming University of Science and Technology,Kunming 650500,China)

机构地区：[1]昆明理工大学机电工程学院,昆明650500

出　　处：《功能材料》2024年第6期6138-6147,共10页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(51165012)。

摘　　要：如何在纳米磁流体的磁流变效应和沉降稳定性之间取得平衡是值得研究的问题,增大颗粒尺寸可能是解决这一问题很好的选择。采用可控的化学共沉淀法合成了粒径约为25 nm的Fe_(3)O_(4)磁性颗粒,并对其进行了物相分析和磁性能表征。以肉豆蔻酸为表面活性剂、RP4350型航空液压油为分散相制备了纳米磁流体,其在强磁场下能长时间保持稳定,适用温度范围为-35~95℃。研究了纳米磁流体磁流变特性随磁场强度和温度的变化规律。结果表明,在低温和强磁场的作用下,纳米磁流体具有更大的屈服应力,最高可达0.16 kPa,即使在屈服以后,样品也能表现出更强的磁黏效应。采用振幅扫描对纳米磁流体动态流变特性进行了测试。磁场强度的增大和温度的降低可以有效增强纳米磁流体的抗剪切能力,从而导致储能模量的升高;线性粘弹性(LVE)区、储存模量和损失模量的交叉点也均会向更高应变幅值移动。这些发现有助于大颗粒在纳米磁流体中的研究,可以为其在更宽温度中的应用提供指导。It is worth studying how to strike a balance between the magnetorheological effect and sedimentation stability in magnetic nanofluids,and the use of larger nanoparticles has been identified as a promising solution.Fe_(3)O_(4) magnetic particles with a size of approximately 25 nm were synthesized using a controlled chemical co-precipitation method,and their phase composition and magnetic properties were characterized.Magnetic nanofluids were prepared using myristic acid as surfactant and RP4350 aviation hydraulic oil as dispersed phase,which exhibited prolonged stability under strong magnetic fields,with applicable temperatures ranging from-35℃to 95℃.The variations in magnetorheological properties with magnetic field strength and temperature were investigated.The results reveal that under the influence of low temperatures and strong magnetic fields,the magnetic nanofluids exhibited significantly higher yield stress,reaching a maximum of 0.16 kPa.Even after yielding,the samples displayed stronger magnetoviscous effect.Dynamic rheological characteristics of magnetic nanofluids were examined using amplitude sweep measurements.The increase in magnetic field strength and the decrease in temperature can effectively enhance the shear resistance of the nanomagnetic fluid,which leads to the elevation of the storage modulus.Furthermore,the linear viscoelastic(LVE)region and the crossover point of the storage modulus and loss modulus also shift towards higher strain amplitudes.These findings contribute to the research on magnetic nanofluids prepared with larger particles and provide guidance for their applications over a wider temperature range.

关 键 词：纳米磁流体 沉降稳定性 磁流变特性 粘弹性 温度 

分 类 号：TB34[一般工业技术—材料科学与工程]