Thermal Stability Enhancement of Magnetorheological Grease with Cobalt-Ferrite Particles as Additive

• Published in: AIP Conference Proceedings
• Main Author: Tarmizi S.M.A.; Nordin N.A.; Mazlan S.A.; Al Hafiz Savukkath Ali S.; Aziz S.A.A.; Mohamad N.; Khairi M.H.A.
• Format: Conference paper
• Language: English
• Published: American Institute of Physics 2024
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85206841215&doi=10.1063%2f5.0227794&partnerID=40&md5=babc2c0201022101dc99c5156c10fea0

Magnetorheological (MR) grease is one of the smart materials that owing excellent properties that can be altered and changed significantly with the presence of a magnetic field. However, thermal stability of MR grease is one of the crucial issues that restricted the efficiency of MR grease in MR applications since the induced heat to the material would affect the resultant properties of the material. In this study, the thermal behavior of MR grease with 1wt.% of cobalt-ferrite (CoFe2O4) were analyzed. The CoFe2O4 particles was synthesized via co-precipitation method. The synthesized particles were characterized in terms of morphological by using field Emission scanning electron microscope (FESEM) and magnetic properties by Vibrating Sample Magnetometer (VSM). Then, the synthesized particles were mixed with grease and carbonyl iron particles (CIPs) by using a mechanical stirrer. The thermal properties of the MR grease samples in terms of conductivity were tested by using KD2Pro. Additionally, rheometer was used to examine the MR effect of MR grease under magnetic field sweep at different applied temperatures. The results showed that the synthesized particles formed in polygonal shape with 68.9 emu/g meanwhile CIPs are in spherical shape with 125 emu/g of magnetic saturation, Ms. Moreover, the thermal conductivity of MR grease increased as the temperature increased, particularly with presence of CoFe2O4 due to the Brownian motion by 178.69%, at 65oC. The storage modulus of the MR grease samples also showed an increasing trend with the addition of CoFe2O4 and with the magnetic field intensity increased, although the induced temperature also increased. © 2024 American Institute of Physics Inc.. All rights reserved.