Synthesis and Magnetorheology Study of Iron Oxide and Iron Cobalt Oxide Suspensions

Abstract

This study investigates the magnetorheology (MR) of polydimethylsiloxane (PDMS) that contains magnetic powders of various compositions, shapes, and concentrations. Two magnetic powders, Fe3O4and CoFe2O4, were synthesized. TEM images reveal that a powder of spherical particles was obtained at high temperature. A powder with nonspherical star shape was synthesized at low temperature. A rheological test confirmed a typical Bingham behavior for all the MR fluids prepared in this study. Experimental results demonstrated that the cobalt ferrite exhibited a more superior yield stress than the ferrite compound. A magnetic powder of larger particles was found to have higher yield stress. Moreover, the spherical particles yielded a higher yield stress than the star-shaped particles. The “saturated magnetic strength” increased with the loading of the magnetic powder. Finally, the results demonstrate that 12 wt% CoFe2O4nanopowder (10 nm) dispersed in the PDMS liquid exhibited a large range of yield stresses (0 to 644 Pa).

Synthesis, characterization and magnetorheological study of 3-aminopropyltriethoxysilane-modified Fe3O4nanoparticles

“…When the magnetic field was turned off, the shear stress was confronted with a sudden decrease and destroyed the chain-like structures. The decrease of shear stress with time is related to gradual distortion of aggregate structures thatindicatethe presence of larger size particles in the MR fluid [31].…”

Near-field magnetostatics and Néel–Brownian interactions mediated magneto-rheological characteristics of highly stable nano-ferrocolloids

“…The present study involves a novel methodology wherein the base matrix itself acts as the protective coating agent and provides long term stability to the system, without compromising its magnetic properties. Furthermore, the magnetoviscous properties observed in the present class of colloid is superior in magnitude and applicability than similar colloids which involve nanoscale iron 12 or nickel/cobalt 13 particles as the dispersed magnetic media 14 . Since production of size controlled SPIONs are relatively easier, less expensive and do not suffer the disadvantages of oxidation during use than metallic magnetic nanoparticles, the present colloids are superior from materials as well as utility point of view.…”

Solvothermal synthesis, characterization, and magnetorheological study of zinc ferrite nanocrystal clusters

“…When the magnetic field is turned off, the shear stress is confronted with a sudden decrease and destroys the chain-like structures. The decrease in shear stress with time is thought to be related to gradual distortion of aggregate structures, which indicates the presence of ZnFe 2 O 4 particles with larger size in the MR fluid (Rwei et al, 2013 suspension. This phenomenon is attributed to the reduced particle-fluid density mismatch.…”