Rheological properties of magnetorheological suspensions based on core–shell structured polyaniline-coated carbonyl iron particles

Abstract

The sedimentation caused by the high density of suspended particles used in magnetorheological fluids is a significant obstacle for their wider application. In the present paper, core-shell structured carbonyl ironpolyaniline particles in silicone oil were used as a magnetorheological suspension with enhanced dispersion stability. Bare carbonyl iron particles were suspended in silicone oil to create model magnetorheological suspensions of different loading. For a magnetorheological suspension of polyaniline-coated particles the results show a decrease in the base viscosity. Moreover, the polyaniline coating has a negligible influence on the MR properties under an external magnetic field B. The change in the viscoelastic properties of magnetorheological suspensions in the small-strain oscillatory shear flow as a function of the strain amplitude, the frequency and the magnetic flux density was also investigated.

Study on the Preparation Process and Properties of Magnetorheological Fluid Treated by Compounding Surfactants

“…During recent twenty years, many researchers have suggested a variety of ways to improve the sedimentation stability of MR fluid, For example, adding different types of surfactants [8][9][10][11], adding carbon nano-tube or nanosized particles magnetic fluid [12,13], preparing special structure particles [14][15][16], the treatment of plasma [17]. Among them, coating particles with different additives is the most effective way for obtaining stable MR fluid [18] [21].…”

Magnetorheology of core-shell carbonyl iron/ZnO rod-like particle silicone oil suspensions under oscillatory shear

“…Nowadays, material exhibiting this behaviour repeatedly can find various applications as shock absorbers [5] or also in the medical application in the local cancer hyperthermia treatment [9]. In order to obtain the highest MR efficiency of the suspensions usually ferromagnetic particles with low value of coercivity dispersed in medium with negligible magnetic properties are employed [11,12]. Furthermore, sedimentation stability is another factor significantly influences the MR efficiency.…”

“…In order to obtain the highest MR efficiency of the suspensions usually ferromagnetic particles with low value of coercivity dispersed in medium with negligible magnetic properties are employed [11,12]. Furthermore, sedimentation stability is another factor significantly influences the MR efficiency.…”

Core-shell Structured Polypyrrole-coated Magnetic Carbonyl Iron Microparticles and their Magnetorheology

“…If the magnetic material is used in a shell layer, a good bonding of the shell to the non-magnetic core is required to prevent eventual fragmentation in shearing [10]. Thus, better variant is based on the use of magnetic material as a core, which enhances also the chemical and oxidation stability [11,12]. The use of both types of core-shell particles results in an improved system stability (i.e.…”

“…The use of both types of core-shell particles results in an improved system stability (i.e. reduced density of dispersed particles and their better compatibility with carrier medium) and may also promote the MR performance defined as a difference between apparent viscosities in the absence and presence of the external magnetic field [11].…”