This review of MRF (magnetorheological fluids or MR fluids) brings out the challenges in methods of preparation, difficulties encountered in storage and use, and possible solutions to overcome the challenges. Magnetorheological fluid in the rheological fluid domain has found use due to its ability to change its shear strength based on the applied magnetic field. Magnetorheological fluids are composed of magnetizable micron-sized iron particles and a non-magnetizable base or carrier fluid along with additives to counter sedimentation and agglomeration. Magnetorheological fluids can respond to external stimuli by undergoing changes in physical properties thus enabling several improved modifications in the existing technology enhancing their application versatility and utility. Thus, magnetorheological fluid, a rheological material whose viscosity undergoes apparent changes on application of magnetic field, is considered as a smart material. Such materials can be used for active and semi-active control of engineering systems. Many studies on the designs of systems incorporating MR fluids, mainly for vibration control and also for other applications including brakes, clutches, dynamometers, aircraft landing gears, and helicopter lag dampers, have emerged over last couple of decades. However, the preparation as well as the maintenance of magnetorheological fluids involves several challenges. Sedimentation is a major challenge, even when stored for moderate periods of time. A comprehensive review is made on the problems confronted in the preparation of magnetorheological fluids as well as sustenance of the properties, for use, over a long period of time. Other problems encountered include agglomeration and in-use thickening (IUT) as well as rusting and crusting. Of interest is the mitigation of these problems so as to prepare fluids with satisfactory properties, and such solutions are reviewed here. The control of magnetorheological fluids and the applications of interest are also reviewed. The review covers additives for overcoming challenges in the preparation and use of magnetorheological fluids that include incrustation, sedimentation, agglomeration, and also oxidation of the particles. The methodology to prepare the fluid along with the process for adding selected additives was reviewed. The results showed an improvement in the reduction of sedimentation and other problems decreasing comparatively. A set of additives for addressing the specific challenges has been summarized. Experiments were carried out to establish the sedimentation rates for compositions with varying fractions of additives. The review also analyzes briefly the gaps in studies on MR fluids and covers present developments and future application areas such as haptic devices.

中文翻译：

---

磁流变液的制备和使用中的挑战和解决方案的回顾

这篇对MRF（磁流变液或MR液）的评论提出了制备方法方面的挑战，存储和使用中遇到的困难以及克服这些挑战的可能解决方案。流变流体领域中的磁流变流体因其能够根据施加的磁场改变其剪切强度的能力而得到使用。磁流变流体由可磁化的微米级铁颗粒和不可磁化的基液或载液以及添加剂组成，以抵抗沉降和团聚。磁流变流体可以通过经历物理性质的变化来响应外部刺激，从而可以对现有技术进行多种改进，从而增强其应用的多功能性和实用性。因此，磁流变液 粘度在施加磁场时发生明显变化的流变材料被认为是一种智能材料。此类材料可用于工程系统的主动和半主动控制。在过去的几十年中，已经出现了许多有关包含MR流体的系统设计的研究，这些系统主要用于振动控制以及其他应用，包括制动器，离合器，测功机，飞机起落架和直升机后备阻尼器。然而，磁流变液的制备和维护涉及若干挑战。沉淀物是一个主要的挑战，即使存储时间很短也是如此。对磁流变液的制备中所面临的问题以及长期使用后的性能维持进行了全面回顾。遇到的其他问题包括结块和使用中增稠（IUT）以及生锈和结皮。令人感兴趣的是减轻这些问题以便制备具有令人满意的性能的流体，并且在本文中综述了这种解决方案。还回顾了磁流变流体的控制和感兴趣的应用。这篇综述涵盖了克服磁流变液制备和使用中挑战的添加剂，这些挑战包括结垢，沉淀，结块以及颗粒氧化。回顾了制备流体的方法以及添加所选添加剂的过程。结果表明，在减少沉降方面有所改善，其他问题也有所减少。总结了用于解决特定挑战的一组添加剂。进行实验以确定具有不同分数添加剂的组合物的沉降速率。审查还简要分析了MR流体研究的差距，并涵盖了当前的发展和未来的应用领域，如触觉设备。