Magnetorheological fluid based on amorphous Fe-Si-B alloy magnetic particles

2021 ◽  
pp. 1045389X2110643
Author(s):  
Chuncheng Yang ◽  
Zhong Liu ◽  
Xiangyu Pei ◽  
Cuiling Jin ◽  
Mengchun Yu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Rheological Property ◽  
Magnetic Particles ◽  
Annealing Treatment ◽  
Magnetorheological Fluid ◽  
The Stability ◽  
The Magnetic Field ◽  
Amorphous Particle ◽  
Better Than

Magnetorheological fluids (MRFs) based on amorphous Fe-Si-B alloy magnetic particles were prepared. The influence of annealing treatment on stability and rheological property of MRFs was investigated. The saturation magnetization ( Ms) of amorphous Fe-Si-B particles after annealing at 550°C is 131.5 emu/g, which is higher than that of amorphous Fe-Si-B particles without annealing. Moreover, the stability of MRF with annealed amorphous Fe-Si-B particles is better than that of MRF without annealed amorphous Fe-Si-B particles. Stearic acid at 3 wt% was added to the MRF2 to enhance the fluid stability to greater than 90%. In addition, the rheological properties demonstrate that the prepared amorphous particle MRF shows relatively strong magnetic responsiveness, especially when the magnetic field strength reaches 365 kA/m. As the magnetic field intensified, the yield stress increased dramatically and followed the Herschel-Bulkley model.

Magnetorheological Fluid for Levitation Migration Technology

2010 ◽  
Vol 148-149 ◽  
pp. 826-831
Author(s):  
Xu Lin Hu ◽  
Yang Guang ◽  
Pan Chao Cui
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Circuit Design ◽  
Magnetic Fluid ◽  
Magnetic Force ◽  
Magnetic Circuit ◽  
Magnetorheological Fluid ◽  
Directional Migration ◽  
Dispersed Particles ◽  
The Magnetic Field

The dispersed particles of magnetic fluid form stable chain-like clusters under the magnetic field, and shows “the flowing is controllable and the shape is controllable” effect. Based on this characteristic, using migration magnetic acted on the magnetic fluid, the object directional migration can be realize, then the magnetic fluid form ribbon at the same time, has the similar fluctuation behavior. The magnetic fluid aerosol migration principle, the aerosol magnetic circuit design, the magnetic field strength and the magnetic force were separately discussed in this paper. The magnetic fluid hover height using the MSL micrometer dial has determined and aerosol migration feasibility has confirmed using the experiment.

An experimental study on the effects of temperature and magnetic field strength on the magnetorheological fluid stability and MR effect

Soft Matter ◽  
2015 ◽  
Vol 11 (22) ◽  
pp. 4453-4460 ◽  
Author(s):  
Yahya Rabbani ◽  
Mahshid Ashtiani ◽  
Seyed Hassan Hashemabadi
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Field Strength ◽  
Rheological Properties ◽  
Carbonyl Iron ◽  
Silicone Oil ◽  
Magnetorheological Fluid ◽  
Effects Of Temperature ◽  
The Stability ◽  
Mr Effect

In this study, the stability and rheological properties of a suspension of carbonyl iron microparticles (CIMs) in silicone oil were investigated within a temperature range of 10 to 85 °C.

The Preparation of Magnetic Particles and Optimization Research

2017 ◽  
Vol 753 ◽  
pp. 269-273
Author(s):  
Jia Bin Wang ◽  
Dong Zhang ◽  
Tian Hang Li
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Weak Magnetic Field ◽  
Magnetic Particles ◽  
Optimal Conditions ◽  
Preparation Conditions ◽  
Silane Coupling ◽  
The Magnetic Field ◽  
Single Factor Experiment

To resolve the problem of weak magnetic field strength of magnetic materials in wastewater treatment, the methods of preparation of magnetic particles was explored. The main influencing factors of magnetic field strength were investigated using single factor experiment. Results suggested that optimal preparation conditions were as follows: 2% silane coupling agent, 12% PVA/ SA, magnetizing time 1 h, and 5% nano Fe3O4 powder. Magnetic particles were prepared based on the optimal conditions and the magnetic field strength was 0.85mT.

Experimental study on tensile mechanical properties of magnetorheological fluid

2020 ◽  
Vol 34 (08) ◽  
pp. 2050070
Author(s):  
Weicheng Wang ◽  
Yiping Luo ◽  
Meng Ji
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Tensile Stress ◽  
Magnetic Particles ◽  
Surface Characteristics ◽  
Magnetorheological Fluid ◽  
Maximum Tensile Stress ◽  
High Permeability ◽  
Soft Magnetic ◽  
The Magnetic Field

Magnetorheological fluid (MRF) is a kind of suspension composed of a nonconducting magnetic liquid and small soft magnetic particles with high permeability and low hysteresis. The tensile mechanical properties of MRF reflect its important mechanical properties. In this study, a testing device is designed to investigate the tensile mechanical properties of MRF in accordance with the plate method theory. First, the magnetic field is selected to analyze the influence of different gap sizes on the magnetic field. The magnetic field strength decreases as the gap increases. Second, a testing platform for tensile mechanical properties is built, and the tensile mechanical properties of MRF are experimentally studied under different magnetic field strengths, tensile speeds and surface characteristics. Experimental results show that the stronger the magnetic field, the greater the tensile yield stress. The maximum tensile stress at different velocities is nearly the same. Different surface characteristics affect tensile stress.

Influence of magnetic field, magnetic particle percentages, and particle diameters on the stiffness of magnetorheological fluids

2020 ◽  
Vol 31 (20) ◽  
pp. 2312-2325
Author(s):  
Wei Sun ◽  
Jingjun Yu ◽  
Yueri Cai
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Random Distribution ◽  
Magnetic Field Intensity ◽  
Variable Stiffness ◽  
Magnetorheological Fluid ◽  
Physical Transformation ◽  
Change State ◽  
The Magnetic Field

Generally, variable stiffness joints of soft robots are generally fabricated using thermoplastics and elastomers due to their ability to change state from rigid to flexible and vice versa. However, these materials require a considerable amount of time to change states and are associated with other technical drawbacks. We demonstrate the instantaneous physical transformation of a Ga-based magnetorheological fluid called Gallistan from a liquid to a viscoelastic solid, and precisely controlled within milliseconds under an applied magnetic field. We studied the magnetic properties of a magnetorheological fluid by dispersing Fe particles in a Ga–In–Sn eutectic alloy. Theoretical analysis of the movement of two particles under magnetic field and typical defects in dipolar chains is studied. The experimental results showed a reversible change in Young’s modulus depending not only on the magnetic field intensity but also the percentage of magnetic particles. Thus, we confirm that the arrangement of magnetic particles transition from random distribution to stable chain structures in the magnetic field. Based on the bi-material nested cantilever beam, the variable stiffness joints can also be precisely adjusted under a magnetic field. In future, this property of the magnetorheological fluid will help develop a variable stiffness joint for soft robotics.

PARTICLE DYNAMICS OF STRUCTURE FORMATION AND DISINTEGRATION IN A MODEL MAGNETORHEOLOGICAL FLUID

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2314-2320 ◽  
Author(s):  
S. CUTILLAS ◽  
J. LIU
Keyword(s):  
Magnetic Field ◽  
Refractive Index ◽  
Correlation Function ◽  
Field Strength ◽  
Structure Formation ◽  
Magnetorheological Fluid ◽  
Particle Dynamics ◽  
Diffusing Wave Spectroscopy ◽  
Induced Structure ◽  
The Magnetic Field

Using diffusing-wave spectroscopy (DWS), we studied experimentally the particle dynamics for a density matched superparamagnetic polystyrene colloid in a refractive index nearly matched multiple-layered cell. Particle dynamics is probed during structure formation and disintegration, when a 0.2 Hz square-wave magnetic field was turned on for 4 s and off for 1 s. The correlation function shows that the particles move slower and more restricted when the magnetic field is on. Even during the off cycle of the magnetic field, the particles' motion is not free but still constrained with a less degree than that when the field is on. Thus, it takes more than 1 s for the induced structure to disintegrate. As the magnetic field strength increases, so does the degree of constrain for both the on and off cycle of the magnetic field and the differences between them. Modified telegrapher theory is found to be valid for our strongly absorbing and limited multiple scattering sample.

A MAGNETIC FIELD STABILIZATION CIRCUIT

1950 ◽  
Vol 28a (1) ◽  
pp. 67-72 ◽  
Author(s):  
L. Katz ◽  
P. A. Forsyth ◽  
L. F. Cudney ◽  
G. W. Williams ◽  
H. E. Johns ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Alternating Current ◽  
Rectifier Circuit ◽  
Full Wave ◽  
The Magnetic Field ◽  
Alternating Voltage ◽  
Better Than

The paper describes the apparatus used to stabilize the magnetic field of a large electromagnet. A rotating coil placed in the magnetic field generates an alternating voltage which is proportional to the strength of the field. Variations in this rotor voltage are used to control the current supplied to the electromagnet in such a manner as to keep the field constant. By means of a calibrated held control the magnetic field strength may be adjusted to any value between 500 and 6000 gauss. The current for the electromagnet is obtained by rectifying 60 cycle alternating current in a full wave, thyratron, rectifier circuit. This current is controlled by a pulse circuit which governs the fraction of each cycle during which the thyratrons are conducting. The stabilization at any held setting is better than 1 part in 1000.

Phase Change and Magneto-Rheology of a Suspension Composed of Magnetic Rod-Like Particles

2015 ◽  
Author(s):  
Akira Satoh
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Phase Change ◽  
Rheological Properties ◽  
Magnetic Field Strength ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Magneto Rheological ◽  
Aggregate Structures ◽  
The Magnetic Field

Magnetic particle suspensions have a great potential as an application in engineering fields and therefore a variety of studies on these functional fluid have been conducted in various fields, including the traditional fluid engineering field and the recent bioengineering field such as an application to a drug delivery system. The main application target in the fluid engineering field may be mechanical dampers and actuators. Magneto-rheological properties significantly depend on the formation of aggregates of magnetic particles. In the present study, we focus on a ferromagnetic rod-like particle suspension to discuss the phase change of aggregate structures of magnetic rod-like particles and the magneto-rheological properties that are strongly dependent on the formation of aggregate structures. The characteristics of the phase change are mainly investigated by Monte Carlo simulations for thermodynamic equilibrium and the magneto-rheological properties are done by Brownian dynamics simulations in a simple shear flow situation. From the latter simulations, we discuss mainly the dependence of the magneto-rheological effect on the phase change of aggregate structures. In a weak applied magnetic field, magnetic rod-like particles tend to aggregate to form raft-like clusters if the magnetic particle-particle interaction is much stronger than thermal energy. If the magnetic field strength is increased, these raft-like clusters drastically dissociate into single-moving particles at a certain value of the magnetic field strength, that is, the phase change in aggregate structures arises. The net viscosity and viscosity components exhibit complex dependence on the magnetic field strength, which is mainly due to the raft-like cluster formation of magnetic particles.

scholarly journals Reinforced Smart Foams Produced with Time-Profiled Magnetic Fields

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 24
Author(s):  
Daniele Davino ◽  
Marco D’Auria ◽  
Roberto Pantani ◽  
Luigi Sorrentino
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Constant Magnetic Field ◽  
Magnetic Particles ◽  
Relative Sensitivity ◽  
Foaming Process ◽  
Geometrical Features ◽  
The Matrix ◽  
Field Lines ◽  
The Magnetic Field

Polymeric smart foams are lightweight and multifunctional porous materials that are sensitive to the magnetic field due to the presence of magnetic particles embedded in the matrix. Recently, a constant magnetic field has been exploited to align the particles along the magnetic field lines during the formation of the porous structure. In this paper, a new field-structuring process was developed that makes use of a time-profiled magnetic field during the foaming process to control the geometrical features of the particles aggregates. The effects of magnetic field strength as well as the switch-on and switch-off times on the magnetoelastic behavior of the smart foams were investigated. It was proven that the alignment of the particles results in both a strong relative sensitivity to the magnetic field and a positive stress change, whose extent depends on the geometrical features of the developed aggregates.

Influence of Nano-Fe3O4 Addition on the Stability of Magnetorheological Fluid

2011 ◽  
Vol 261-263 ◽  
pp. 529-532 ◽  
Author(s):  
Hong Liang Cuan ◽  
Xiao Mei Luo ◽  
Shi Quan Liu
Keyword(s):  
Magnetic Field ◽  
Magnetic Circuit ◽  
Magnetorheological Fluid ◽  
Iron Particles ◽  
Ansys Software ◽  
Parallel Disk ◽  
Mass Fractions ◽  
The Stability ◽  
Low Magnetic Field ◽  
The Magnetic Field

Based on the uniformity of magnetic field in shear circle, low magnetic field, and inconvenient of injecting magnetorheological fluid (MRF), the rotational parallel disk instrument for measuring the shear stress of MRF made by ourselves was improved. The magnetic circuit of the instrument was optimized using Ansys software, the parts and structure of leaking magnetic field were improved, and the uniformity of the magnetic field in shear circle plates was strengthen; when the current was 1.65A, the average magnetic field in shear circle plates was 0.9T. Then the influence on MRF by using different mass fractions of nano-Fe3O4 was researched, which indicate when the ration between the mass of nano-Fe3O4 and that of carbonyl iron particles is 5%, the characteristic of MRF is best.

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