A1 Refereed original research article in a scientific journal
Characterization of bidisperse magnetorheological fluids utilizing maghemite (γ-Fe2O3) nanoparticles synthetized by flame spray pyrolysis
Authors: Jonkkari I, Sorvali M, Huhtinen H, Sarlin E, Salminen T, Haapanen J, Makela JM, Vuorinen J
Publisher: IOP PUBLISHING LTD
Publishing place: BRISTOL
Publication year: 2017
Journal: Smart Materials and Structures
Journal name in source: SMART MATERIALS AND STRUCTURES
Journal acronym: SMART MATER STRUCT
Article number: 095004
Volume: 26
Issue: 9
Number of pages: 10
ISSN: 0964-1726
DOI: https://doi.org/10.1088/1361-665X/aa7f7d
Abstract
In this study we have used liquid flame spray (LFS) process to synthetize.-Fe2O3 nanoparticles of two different average sizes. Different sized nanoparticles were generated with two different liquid precursor feed rates in the spray process, higher feed rate resulting in larger nanoparticles with higher saturation magnetization. The nanoparticles were used in bidisperse magnetorheological fluids to substitute 5% of the micron sized carbonyl iron particles. To our knowledge this is the first time particles synthetized by the LFS method have been used in magnetorheological fluids. The bidisperse fluids showed significantly improved sedimentation stability compared to a monodisperse suspension with the same solid concentration. The tradeoff was an increased viscosity without magnetic field. The effect of the nanoparticles on the rheological properties under external magnetic field was modest. Finally, the dynamic oscillatory testing was used to evaluate the structural changes in the fluids under magnetic field. The addition of nanoparticles decreased the elastic portion of the deformation and increased the viscous portion.
In this study we have used liquid flame spray (LFS) process to synthetize.-Fe2O3 nanoparticles of two different average sizes. Different sized nanoparticles were generated with two different liquid precursor feed rates in the spray process, higher feed rate resulting in larger nanoparticles with higher saturation magnetization. The nanoparticles were used in bidisperse magnetorheological fluids to substitute 5% of the micron sized carbonyl iron particles. To our knowledge this is the first time particles synthetized by the LFS method have been used in magnetorheological fluids. The bidisperse fluids showed significantly improved sedimentation stability compared to a monodisperse suspension with the same solid concentration. The tradeoff was an increased viscosity without magnetic field. The effect of the nanoparticles on the rheological properties under external magnetic field was modest. Finally, the dynamic oscillatory testing was used to evaluate the structural changes in the fluids under magnetic field. The addition of nanoparticles decreased the elastic portion of the deformation and increased the viscous portion.
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