Magnetorheological fluids based on core–shell carbonyl iron particles modified by various organosilanes: synthesis, stability and performance

Soft Matter ◽  
2021 ◽  
Author(s):  
Alena Ronzova ◽  
Michal Sedlacik ◽  
Martin Cvek

Implications of the organosilane-coated particles on the utility properties of MR fluids.

2007 ◽  
Vol 334-335 ◽  
pp. 193-196
Author(s):  
Jae Lim You ◽  
B.J. Park ◽  
I.B. Jang ◽  
Hyoung Jin Choi

To enhance dispersion stability of magnetorheological (MR) fluids, hybrid magnetic particles of carbonyl iron (CI)/ poly(vinyl butyral) (PVB) with core/shell microstrcutre (CI-PVB) were prepared, since pure magnetic CI based MR fluid systems show severe sedimentation of the CI particles due to the large density mismatch with the carrier liquid and difficulties in redispersion after caking. The composite particles of CI-PVB have a lower density than that of the pure CI particles, while exhibiting almost original magnetic property of the CI. Both CI and CI-PVB particles were dispersed in mineral oil (20 vol%) and their MR characteristics were examined via a rotational rheometer with a magnetic field supplier. Various characterizations of the CI-PVB particles were performed via SEM, TEM and FT-IR. Both yield stress and flow curve of shear stress as a function of shear rate of the MR fluids were investigated under applied magnetic field strengths.


2005 ◽  
Vol 19 (07n09) ◽  
pp. 1121-1127 ◽  
Author(s):  
A. SHIBAYAMA ◽  
T. OTOMO ◽  
Y. AKAGAMI ◽  
K. SHIMADA ◽  
T. FUJITA

In this study, a magneto-rheological fluid dispersed by silica-coated iron was developed and its properties such as fluid viscosity (shear stress or shear rate) and abrasion were investigated. The metallic iron coated by silica dispersed in magneto-rheological fluid was prepared by H 2 reducing of precipitated magnetite ( Fe 3 O 4). Then, the magneto-rheological fluid (MR fluid) for the seal was prepared with silica-coated iron or carbonyl iron (HQ type; diameter of 1.6-1.9 10-6m) and two solvent oils i.e. silicon oil (SH200cv, 10000cSt) and CVT oil (T-CVTF, automobile transmission oil). It was observed that the MR fluid viscosity of CVT oil with HQ particles is lower in every fluid condition. Furthermore, the surface roughness of polyvinyl plate after abrasion test for MR fluid with silica coated iron and CVT oil as solvent was higher compared to the other types of MR fluids. The results indicated that carbonyl iron (spherical particles) and silica-coated iron particles dispersed in silicon oil are feasible to be used where the low abrasion in mechanics is required.


Author(s):  
Michal Sedlacik ◽  
Vladimir Pavlinek ◽  
Marian Lehocky ◽  
Ales Mracek ◽  
Ondrej Grulich ◽  
...  

2007 ◽  
Vol 21 (28n29) ◽  
pp. 4849-4857 ◽  
Author(s):  
S. MANTRIPRAGADA ◽  
X. WANG ◽  
F. GORDANINEJAD ◽  
B. HU ◽  
A. FUCHS

The rheological properties of novel MR fluids are characterized using a parallel plate MR shear rheometer. In these MR fluids the surface of iron particles is coated with a polymer. The rheological properties are measured and compared at various magnetic field strengths, shear rates and strain amplitudes. It has been shown that these MR fluids exhibit stable and desirable rheological properties such as, low viscosity and high yield stress.


2015 ◽  
Vol 293 (9) ◽  
pp. 2647-2654 ◽  
Author(s):  
Woo Jin Ahn ◽  
Hyo Seung Jung ◽  
Seung Hyuk Kwon ◽  
Cheng Hai Hong ◽  
Hyoung Jin Choi

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