| Summary: | MR foam is a magnetically permeable solid material that composed of micron-sized magnetic particles known as carbonyl iron (CIPs) that are embedded in a porous absorbent matrix of foam. There are two types of methods to fabricate MR foams known as ex situ and in situ methods. In particular, the methods related to the location of CIPs in the structure of MR foams such that in situ MR foam contained of CIPs in the struts of foam. Meanwhile, ex situ MR foam contained of CIPs in the pores of foam rather than in the struts structure. Correspondingly, resultant magnetostriction of each type of MR foam would be different as magnetic responsiveness of MR foams towards the applied magnetic fields would be differ as well. Therefore, three MR foams were fabricated via three methods particularly, ex situ, in situ, and hybrid as a combination of ex situ and in situ methods. Then, the samples underwent the magnetostriction test at various magnetic fields from 0 to 0.8 T using a rheometer that equipped with electromagnetic device. The results show that the hybrid MR foam exhibited the highest magnetostriction, about 36.74%, followed by ex situ- and in situ MR foams. It is attributed to the CIPs that were located in the struts and pores of MR foam which result in a stronger magnetic force between the particles, and towards the applied magnetic fields. © 2024 American Institute of Physics Inc.. All rights reserved.
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