Improvement of magnetorheological greases with superparamagnetic nanoparticles

Mohamad, Norzilawati; Mazlan, Saiful Amri; Choi, Seung‐Bok; Halim, Naim Abdul

doi:10.1051/matecconf/201815902066

Cited by 8 publications

(3 citation statements)

References 12 publications

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“…However, the dynamic yield stress of MRG showed an insignificant improvement. Mohamad et al [ 14 ] introduced another type of nanoparticle additive in MRG, namely, super-paramagnetic γ-Fe 2 O 3 . The addition of 1 wt % additive was capable of lowering the off-state viscosity and increased the on-state viscosity of MRG.…”

Section: Introductionmentioning

confidence: 99%

Rheological Performance of Magnetorheological Grease with Embedded Graphite Additives

et al. 2021

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The use of highly viscous grease as a medium in magnetorheological grease (MRG) provides the benefit of avoiding sedimentation from occurring. However, it limits the expansion of yield stress in the on-state condition, thus reducing the application performance during operation. Therefore, in this study, the improvement in the rheological properties of MRG was investigated through the introduction of graphite as an additive. MRG with 10 wt % graphite (GMRG) was fabricated, and its properties were compared to a reference MRG sample. The microstructure of GMRG was characterized using an environmental scanning electron microscope (ESEM). The rheological properties of both samples, including apparent viscosity, yield stress, and viscoelasticity, were examined using a shear rheometer in rotational and oscillatory modes. The results demonstrated a slight increase in the apparent viscosity in GMRG and a significant improvement in yield stress by 38.8% at 3 A with growth about 32.7% higher compared to MRG from 0 to 3 A. An expansion of the linear viscoelastic region (LVE) from 0.01% to 0.1% was observed for the GMRG, credited to the domination of the elastic properties on the sample. These obtained results were confirmed based on ESEM, which described the contribution of graphite to constructing a more stable chain structure in the GMRG. In conclusion, the findings highlight the influence of the addition of graphite on improving the rheological properties of MRG. Hence, the addition of graphite in MRG shows the potential to be applied in many applications in the near future.

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Section: Introductionmentioning

confidence: 99%

Rheological Performance of Magnetorheological Grease with Embedded Graphite Additives

et al. 2021

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“…Moreover, the author also mentioned that by addition of more than 10 wt.% dilution oil led to decreased stability of the MRG. Aside from that, a few solid based additives in nano-sized that have been introduced in MRG are chromium dioxide, CrO2 [11] and superparamagnetic γ-Fe2O3 [12]. Based on the outcome, it can be concluded that utilizing nanoparticle additives able to improve the stability of low viscosity MRG and at the same time lower the viscosity of MRG at the off-state condition.…”

Section: Introductionmentioning

confidence: 99%

Field-Dependent Viscoelastic Properties of Graphite-based Magnetorheological Grease

Nasir

Nurhazimah²,

Mohamad³

et al. 2022

Int. J. Automot. Mech. Eng.

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This paper highlights the effect of graphite on the dynamic viscoelastic properties of magnetorheological grease (MRG). Two types of MRG namely MRG and graphite-MRG, GMRG with 0 wt.% and 10 wt. % of graphite respectively was synthesized by using a mechanical stirrer. The rheological properties of both sample at various magnetic field strength from 0 to 0.603 T was analyzed via rheometer under oscillatory mode with strain ranging from 0.001 to 1% with fixed frequency at 1 Hz for strain sweep and frequency ranging from 0.1 to 80 Hz at a constant strain of 0.01 % for frequency sweep. Based on the result obtained, the value of storage and loss modulus are dependent on the graphite content. A high value of storage modulus was achieved in the GMRG sample at all applied magnetic field strengths within all frequency ranges. These phenomena related to the contribution of graphite to forming the chain structure with CIPs and offered a more stable and stronger structure as compared with MRG. Moreover, the reduction in the value of loss modulus in GMRG was noticed compared to MRG at on-state conditions reflected by the stable structure obtained by GMRG. Lastly, both samples displayed a strong solid-like (elastic) behavior due to the high value of storage modulus, G’ acquired compared to loss modulus, G’’ at all frequency ranges. Therefore, the utilization of graphite in MRG can be used in wide applications such as brake and seismic dampers.

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“…Though, the dynamic yield stress of MRG showed insigni cant improvement. Nevertheless, Mohamad et al 13 introduced another type of nanoparticle's additive in MRG namely, super-paramagnetic, γ-Fe 2 O 3 . The addition of 1 wt.…”

Section: Introductionmentioning

confidence: 99%

Field-Dependent Rheological Properties of Graphite Based Magnetorheological Grease

Nasir

Nazmi

Mohamad

et al. 2021

Preprint

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The utilization of high viscous grease as a medium in Magnetorheological grease (MRG) has benefits in avoiding the sedimentation from occurred, however, it limits the expansion of yield stress in on-state condition thus reduced the application performance upon operation. Therefore, in present study, improvement of the rheological properties of MRG has been investigated by introduction of graphite as an additive. MRG with 10 wt% of graphite (GMRG) was fabricated and the analysis of the properties was compared to the reference sample, MRG. The microstructure of GMRG was characterized through Environmental Scanning Electron Microscope, (ESEM). While, the rheological properties including apparent viscosity, yield stress and viscoelastic properties for both samples were examined using shear rheometer under rotational and oscillatory mode. The results demonstrated slightly increment of apparent viscosity in GMRG and shows a significant improvement in term of yield stress by 38.8% at 3A with growth about 32.7% higher compared to MRG from 0A to 3A. Also, an expansion of linear viscoelastic region (LVE) from 0.01 to 0.1% was observed in the GMRG credited to the domination of elastic properties on the sample. These results obtained was confirmed based on ESEM that displayed the contribution of graphite towards constructing more stable chain structure in GMRG. In conclusion, this study highlights the influence of graphite towards improving the rheological properties of MRG. Hence, addition of graphite in MRG is a great potential to be applied in many applications in near future.

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Improvement of magnetorheological greases with superparamagnetic nanoparticles

Cited by 8 publications

References 12 publications

Rheological Performance of Magnetorheological Grease with Embedded Graphite Additives

Rheological Performance of Magnetorheological Grease with Embedded Graphite Additives

Field-Dependent Viscoelastic Properties of Graphite-based Magnetorheological Grease

Field-Dependent Rheological Properties of Graphite Based Magnetorheological Grease

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