Effects of corrosion rate of the magnetic particles on the field-dependent material characteristics of silicone based magnetorheological elastomers

Abstract

Carbonyl iron particles (CIPs) embedded in magnetorheological elastomers (MREs) as magnetic filler play a dominant candidate that can affect resultant properties of MREs including the field-dependent viscoelasticity. In this work, the effects of corrosion rate on the rheological properties of MREs are experimentally investigated. The CIPs undergo an accelerated corrosion test in diluted hydrochloric (HCl) acid at various concentrations, particularly at 0.5, 1.0 and 1.5 vol.% for 30 min immersion time, individually. Four samples of CIPs, including the non-corroded one are prepared, and their morphological characterization are observed via field emission scanning electron microscope (FESEM), that equipped with energy dispersive x-ray spectroscopy (EDS) for elemental compositions. In addition, x-ray diffraction (XRD) is used to identify the crystalline phase structure of the samples. In order to examine the corrosion rate of each sample, weight-loss method is used by pressing the CIPs into pellet shape and being immersed in the respective concentrations of HCl. It is shown that the corrosion rate of CIPs is increased with the increasing of HCl concentration in which higher weight loss of the measured pallet CIPs is observed. Meanwhile, the field-dependent rheological properties of MREs are investigated via rheometer to analyze the change in dynamic modulus of MREs such as storage modulus, loss factor and absolute MR effect. These experimental results indicate that MRE samples with higher corrosion rate of CIP exhibit lower storage modulus, loss factor and MR effect, as this subsequently would deteriorate the performance of MRE. Therefore, it is identified that the purity of CIP plays the most important contribution towards the field-dependent viscoelastic properties of MRE for a long period use of the material.

Microcarriers in application for cartilage tissue engineering: Recent progress and challenges

“…It should be noted that some magnetic metals such as cobalt and nickel can cause substantial acute toxicity [ 12 , 330 , 331 ]. Additionally, magnetic particles should be corrosive in the aqueous environments; therefore, the magnetic particles can be coated with protective layers (e.g., silica layers) to enhance their chemical stability [ 332 , 333 ]. In summary, the potential toxicity and the metabolism of the magnetic particles, as well as the large volume and limited workspace of the magnetic targeting devices, remain challenging issues associated with future microcarrier systems development.…”

Systematic Review on the Effects, Roles and Methods of Magnetic Particle Coatings in Magnetorheological Materials

“…This is said to be due to the increasing oxidation of the iron particles in conjunction with the fact that iron oxides have much lower magnetization compared to elemental iron. The effects of corrosion in MR materials have also been discussed in detail by Plachy et al (2018) [ 17 ] and Burhannuddin et al (2020) [ 63 ] in separate works around MRF and MRE, respectively. Furthermore, rougher surfaces of oxidized particles may lead to irregular polishing performance as well as reducing the lifetime of the vessels that contain the MR materials, because rougher surfaces can cause unnecessary friction between the particles and the wall of the vessels after a long operational period [ 57 , 58 , 64 ].…”

Magnetorheological Elastomer based torsional vibration isolator for application in a prototype drilling shaft

“…These experimental results indicate that MRE samples with a higher corrosion rate of CIP exhibit lower storage modulus, loss factor and MR effect, which would subsequently deteriorate the performance of MRE. 29…”