Co0.9Ni 0.1纳米团簇磁流变液的动态屈服行为及速率相关性
Dynamic and rate-dependent yielding behavior of Co0.9Ni0.1 nanocluster based magnetorheological fluids
摘要：
在本文中，我们进行了稳态剪切和振荡磁流变（MR）的研究中含有CoNi纳米团簇的直径为450 nm的磁流体。在不添加任何表面活性剂或还原剂的情况下，以液态多元醇为溶剂，采用常规的均相成核法，在高温下合成了富钴纳米团簇。通过X射线衍射、能谱分析、扫描电镜和透射电镜对样品的成分和形貌进行了分析。通过将15体积%和20体积%的CoNi粉末分散在蓖麻油中制备两种变体的流体样品。室温下稳定的磁剪切研究表明粘塑性行为与更强的依赖性，静态屈服应力磁化比偶极耦合，在动态屈服应力的操作。在恒定剪切速率下的磁扫描测量显示在高磁场下有趣的弛豫。我们还探讨了动态弹性行为，通过振荡磁流变学研究下的应变扫描和频率扫描模式，并显示玻璃化转变现象发生在他们以上的临界剪切振幅。
英文摘要：
In this paper we performed steady shear and oscillatory magnetorheological (MR) studies in magnetic fluids containing CoNi nanoclusters of 450 nm in diameter. Co-rich nanoclusters were synthesized by conventional homogeneous nucleation without any external surfactant or reducing agent in liquid polyol at elevated temperature. The x-ray diffraction, energy dispersive X-Ray analysis, scanning and transmission electron microscopy studies were done for analyzing the sample composition and morphology. Two variants of fluid samples were prepared by dispersing 15 vol% and 20 Vol% of CoNi powders in castor oil. Room temperature steady magnetoshear studies indicate viscoplastic behavior with stronger dependence of static yield stress on magnetization than a dipolar coupling that was operational in the dynamic yield stress. Magnetosweep measurements at constant shear rate showed interesting relaxation at high magnetic fields. We also explored dynamical elastic behavior through oscillatory magnetorheological studies under both strain sweep and frequency sweep modes, and showed glass transition like phenomenon occurring in them above critical shear amplitudes.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
