Magnetic properties of epoxy-bonded iron–gallium particulate composites

Abstract

This paper presents the production process and the results of investigations into the microstructure and magnetic properties of epoxy-bonded iron–gallium (Galfenol) particulate composites. The manufactured composites consist of powdered Fe80Ga20 alloy particles of three different size distributions (ranging from 20 to 200 μm), bonded in an epoxy matrix with a filling factor of 0.80. The filling factor is defined as the ratio of the volume of Fe–Ga powder to the total volume of the composite’s constituents. The microstructure of the powdered alloy has been examined using x-ray diffractometry (XRD), and Mössbauer spectroscopy. Results for the measured magnetic hysteresis loop (B–H curve), static magnetostriction (λ) versus applied field and dynamic relative permeability (μr33) are presented for the alloy in the forms of bulk material, powders and composites subsequently manufactured. The highest value of magnetostriction (360 ppm) has been found in the composite with grain size in the range of 50–100 μm. On reversing the magnetic field direction, large magnetostrictive hysteresis for these samples has been observed. The value of μr33 at a given applied magnetic bias field has been found to decrease with decreasing particle size.

High aspect ratio galfenol flakes for high strain efficiency and sensing performance of magnetostrictive polymer composites

“…14 Comparison of magnetostriction as a function of Galfenol vol% for various magnetostrictive particulate composites available in literature. 23,31,[41][42][43][81][82][83][84][85][86] All results are for a 170 kA m À1 applied field. ME Terfenol-D results were calculated from reported ME coupling and piezoelectric coefficients at the same 170 kA m À1 applied field.…”

“…ME Terfenol-D results were calculated from reported ME coupling and piezoelectric coefficients at the same 170 kA m À1 applied field. 42 10.00 33.9 Epoxy/Galfenol 43 83.80 6.9 Epoxy/Terfenol-D 87 57.00 72.6 Epoxy/Terfenol-D 87 20.00 49.8 Epoxy/Terfenol-D 88 20.00 39.7…”

“…22,37 Analytical and numerical studies suggest that particles of high aspect ratio may offer improved magnetostriction 33,38 and ME coupling 39,40 in magnetostrictive polymer composites. Experimental observations demonstrate improved magnetostriction [41][42][43][44] and ME coupling [35][36][37]45 in these high aspect ratio systems. However, there is a lack of experimental evidence on the influence of particle aspect ratio on their magnetostriction performance and the ME coupling efficiency in polymer composites, especially for the case when low volume fractions are required to minimise leakage currents and improve electrical poling efficiency of the piezoelectric matrix in polymer based-ME composites.…”

Negative Magnetostrictive Paper Formed by Dispersing CoFe 2 O 4 Particles in Cellulose Nanofibers

“…In addition, they are easier to manufacture to the required geometry than the above-mentioned giant magnetostrictive alloys. Previous studies on MPCs have reported Terfenol-D particles [26] and Galfenol particles [27] dispersed through an epoxy resin matrix (Terfenol-D/epoxy and Galfenol/epoxy composites, respectively), Fe-Co alloy particles dispersed through a polyurethane matrix (Fe-Co/PU composites) [28] and various others. Positive magnetostriction values of 1600, 360, and 70 ppm been reported in Terfenol-D/epoxy, Galfenol/epoxy, and Fe-Co/PU, respectively.…”

Flexible Pr‐Doped Fe–Ga Composite Materials: Preparation, Microstructure, and Magnetostrictive Properties

“…The maximum magnetostrictive coefficient of the composite material reaches %70 ppm. Walters et al [5] used low-energy blade milling under a protective argon atmosphere to obtain three different particle-sized Fe 80 Ga 20 alloy powders then mixed with an epoxy binder, and the magnetostriction of the composite was found to be 360 ppm. Gaudet et al [6] used mechanical alloying method to prepare Fe-Ga-based powders and investigate the structure of powder.…”