Enhancement of sensitivity of magnetostrictive foam in low magnetic fields for sensor applications

• Main Authors: Rizuan, Norhaniza, Mazlan, Saiful Amri, Ubaidillah, Ubaidillah, Abdul Aziz, Siti Aishah, Nazmi, Nurhazimah, Yunus, Nurul Azhani
• Format: Article
• Published: Elsevier Ltd 2020
• Subjects: T Technology (General)
• Online Access: http://eprints.utm.my/id/eprint/91898/; http://dx.doi.org/10.1016/j.polymer.2020.123083

Magnetostrictive materials are usually used in sensor technology since they are sensitive to magnetization and strain. Unfortunately, to date, only a few magnetostrictive materials are being used, as the need for a strong magnetic field (1 T) and not sensitive at a low magnetic field. Thus, in this study, a new magneto-active (MA) polyurethane foam was fabricated to obtain a strain at a low magnetic field corresponding to below 1 T. The in-situ fabrication of the MA foam was carried out with various compositions of carbonyl iron particles (CIPs), particularly at 35, 45, 55, 65 and 75 wt%. An analysis of the magnetic properties revealed that all the MA foams showed high magnetic saturation with low remanence values. Furthermore, the MA foam of 75 wt% showed the highest magnetostrictive strain of 1.66% at 0.45 T. The sensitivity of the MA foam is 0.0146%/mT with 42% of improvement. Analyses show MA foam of 75 wt% had a low density, biggest pores and long struts that might have led to high flexibility for elongation to produce a high strain percentage within the practical magnetic field range. Hence, this MA foam can be further utilized for sensor applications.