A study on magnetorheological and sedimentation properties of soft magnetic Fe58Ni42 particles

Abstract

In this study, the samples with two volume fractions (ϕ) of Fe<inf>58</inf>Ni<inf>42</inf> (permalloy) i.e. (ϕ<inf>1</inf> = 25 and ϕ<inf>2</inf> = 30 %) were used as magnetic particles, silicone oil as a carrier fluid, and aluminium disterate as an additive. As received Fe<inf>58</inf>Ni<inf>42</inf> particles surface morphology and composition of the Fe<inf>58</inf>Ni<inf>42</inf> were investigated using field emission scanning electron microscopy (FESEM) coupled with energy dispersive spectroscopy (EDS), respectively. The X-ray Diffraction (XRD) structural information analysis confirmed Fe<inf>58</inf>Ni<inf>42</inf> particles have a face-centered cubic phase, corresponding with the result of the high resolution transmission electron microscopy (HRTEM) characterization technique. The magnetorheological properties were tested via rotational rheometer at four different magnetic field strengths. The results show that sample PMRF-30 has a maximum shear stress, shear viscosity, and dynamic modulus greater than the PMRF-25 sample. In addition, experimental shear stress flow curves are well fitted with Herschel-Bulkley rather than Bingham and Casson rheological models. The permalloy based magnetorheological fluid (PMRF) samples were prepared with a 25 % volume fraction and a 30 % volume fraction of permalloy particles with a sample abbreviation of PMRF-25 and PMRF-30, respectively. Furthermore, the sedimentation stability of suspensions of both the samples was observed using visual inspection. This method result shows the sedimentation ratio with respect to time of 72 h was 31 % and 29 %, respectively. © 2022 Elsevier B.V.