Production and dispersion stability of nanoparticles in nanofluids
Production and dispersion stability of nanoparticles in nanofluids
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DOI：
10.1016/j.powtec.2007.11.020
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发表时间：
2008-08-11
影响因子：
5.2
通讯作者：
Kim, Soo H.
中科院分区：
文献类型：
--
作者：
Hwang, Yujin;Lee, Jae-Keun;Kim, Soo H.
本文介绍了纳米粒子在纳米流体中均匀分散的实验研究。在这项研究中，各种物理处理技术的基础上，两步法，包括搅拌器，超声波浴，超声波破碎机，高压均质器进行了系统的测试，以验证它们的通用性，制备稳定的纳米流体。在表面活性剂存在下，炭黑和银纳米粒子分散在基液中，初始时粒子高度团聚，流体动力学直径分别为330 nm ~ 585 nm。CB和Ag纳米流体通过各种两步法处理后，发现搅拌器、超声浴和超声破碎器对初始颗粒团簇的解团聚过程的性能较差。然而，高压均化器产生的CB和Ag颗粒的平均直径分别为45 μ m和35 μ m，这表明在本研究中采用的各种物理处理技术中，高压均化器是分解悬浮在基液中的聚集的纳米颗粒的最有效的方法。为了制备另一种具有更小的初级纳米颗粒的纳米流体，我们还采用了改进的磁控溅射系统，其中溅射的纳米颗粒被设计成直接与在滚筒上形成的运行的表面活性剂添加的硅油薄膜混合（即一步法）。实验结果表明，采用改进的磁控溅射系统制备的Ag纳米粒子在硅油基流体中分散均匀，粒径约为-3 nm，具有较好的稳定性，表明改进的磁控溅射系统也是一种制备稳定纳米流体的有效方法。(c)2007 Elsevier B.V保留所有权利。
This paper presents an experimental study on the homogeneous dispersion of nanoparticles in nanofluids. In this study, various physical treatment techniques based on two-step method, including stirrer, ultrasonic bath, ultrasonic disruptor, and high-pressure homogenizer were systematically tested to verify their versatility for preparing stable nanofluids. Initially carbon black and silver nanoparticles dispersed in base fluids with the presence of surfactant were found to be highly agglomerated with the hydrodynamic diameter of 330 nin to 585 nin, respectively. After both CB and Ag nanofluids were treated by various two-step methods, stirrer, ultrasonic bath, and ultrasonic disrupter was found to do a poor performance in deagglomeration process for the initial particle clusters. However, the high-pressure homogenizer produced the average diameter of the CB and Ag particles of 45 nin and 35 nin, respectively, indicating that among various physical treatment techniques employed in this study, the high-pressure homogenizer was the most effective method to break down the agglorricrated nanoparticles suspended in base fluids. In order to prepare another nanofluid with much smaller primary nanoparticles, we also employed a modified magnetron sputtering system, in which the sputtered natioparticles were designed to directly mix with the running surfactant-added silicon oil thin film formed on a rolling drum (i.e. one-step method). We observed that Ag nanoparticles produced by the modified magnetron sputtering system were homogeneously dispersed and long-term stable in the silicon oil-based fluid, and the average diarneter of Ag nanoparticles was found to be -3 nm, indicating that the modified magnetron sputtering system is also an effective one-step method to prepare stable nanofluids. (c) 2007 Elsevier B.V All rights reserved.