低温下硅油基纳米磁流体沉降稳定性与黏度特性  

Sedimentation stability and viscosity properties of silicone oil-based magnetic nanofluid at low temperature

作　　者：朱启晨 吴张永[1] 王志强 蒋佳骏 李翔 ZHU Qichen;WU Zhangyong;WANG Zhiqiang;JIANG Jiajun;LI Xiang(College of Mechanical and Electrical Engineering,Kunming University of Science and Technology,Kunming 650550,Yunnan,China)

机构地区：[1]昆明理工大学机电工程学院,云南昆明650550

出　　处：《化工进展》2023年第10期5101-5110,共10页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(51165012);云南省教育厅科学研究基金(2015Y080);昆明理工大学分析测试基金(2021P20191103001)。

摘　　要：传统纳米磁流体存在低温稳定性差、低温黏度高等问题。硅油具有优良的低温性能和黏温特性,是低温纳米磁流体合适的基载液。以硅烷偶联剂KH-550、月桂酸和油酸为分散剂,利用两步法制备了硅油基Ni_(0.5)Zn_(0.5)Fe_(2)O_(4)纳米磁流体。通过扫描电镜(SEM)、X射线衍射仪(XRD)、红外光谱和振动样品磁强计对颗粒形貌、微观结构和磁性能进行了表征,并从多因素对低温下纳米磁流体沉降稳定性与黏度特性进行了研究。结果表明:分散剂形成的空间位阻和载液溶解度共同影响着低温下的稳定包覆,相较于羧酸类分散剂,硅烷偶联剂KH-550表面改性包覆制备的纳米磁流体具有更好的低温沉降稳定性,且凝固后的再分散性最佳;由于偶极间相互作用、范德华力的增强以及流体布朗运动的减弱,磁场会降低纳米磁流体低温沉降稳定性;温度的降低会导致无磁场下纳米磁流体向非牛顿流体类型的转变,并影响磁场下磁场强度、剪切速率与黏度间的平衡关系。制备的硅油基纳米磁流体具有较好的低温性能,可应用于低温工况,有助于今后硅油基纳米磁流体制备技术与性能调控的进一步发展。Conventional magnetic nanofluids suffer from poor stability and high viscosity at low temperatures.Silicone oil is a suitable base carrier fluid for low-temperature magnetic nanofluids due to its excellent low-temperature properties and viscosity-temperature characteristics.In this paper,silicone oil-based Ni_(0.5)Zn_(0.5)Fe_(2)O_(4)magnetic nanofluids were prepared by a two-step method using silane coupling agent KH-550,lauric acid or oleic acid as dispersants.The particle morphology,microstructure and magnetic properties were characterized by scanning electron microscope,X-ray diffactometer,infrared spectrum spectroscopy and vibrating sample magnetometer,and the sedimentation stability and viscosity properties of the magnetic nanofluids at low temperatures were investigated from multiple factors.The results show that the spatial site resistance effect and the solubility of the dispersant in the carrier solution jointly affect the stable coating at low temperature.Compared with carboxylic acid dispersants,the nanomagnetic fluids prepared by surface-modified coating with silane coupling agent KH-550 have better low-temperature sedimentation stability and the best redispersibility after solidification.The magnetic field reduces the low-temperature sedimentation stability of magnetic nanofluids due to enhanced dipole interactions and van der Waals forces as well as weakened Brownian motion of the fluid.The decrease in temperature leads to the transition from magnetic nanofluid to non-Newtonian fluid type without magnetic field and affects the equilibrium relationship between magnetic field strength,shear rate and viscosity under magnetic field.The silicone oil-based magnetic nanofluid prepared in this paper has good low temperature performance and can be applied to low-temperature working conditions.This study contributes to the further development of the preparation technology and performance regulation of silicone oil-based magnetic nanofluid in the future.

关 键 词：纳米磁流体 低温 分散剂 沉降稳定性 黏度特性 磁场 剪切致稀 

分 类 号：TB34[一般工业技术—材料科学与工程] TQ021[化学工程]