Synthesis and investigation of structural, thermal, magnetic, and dielectric properties of multifunctional epoxy/Li0.5Al0.35Fe2.15O4/Al2O3 nanocomposites

Abstract

Until recently, multifunctional epoxy nanocomposites (MENCs) have attracted the attention of many researchers due to their properties which can be tuned for the desired application. For high-frequency microelectronic and optoelectronic device packaging, materials with low dielectric permittivity, low dielectric losses, high dielectric strength, and high thermal conductivity have been required. Toward this goal, epoxy/Li0.5Al0.35Fe2.15O4/Al2O3 (wt.%: (95:5-y:y): y ranges from 1 to 5 wt.% by steps of 1 wt.%) nanocomposites were prepared and investigated. The nanocomposite samples were characterized by X-ray diffraction, FT-IR spectroscopy, transmission electron microscope, scanning electron microscope, and thermogravimetric analyzer. In the present study, the thermal conductivity of the samples is enhanced in the direction of increasing the Al2O3 nanofillers, contrary to the thermal stability. The sigmoid M−H curves of the samples reveal their soft ferrimagnetic nature. As the nonmagnetic Al2O3 nanofillers content increases, the magnetic parameters Ms, Mr, and Ls decrease, while Hc and Sq increase with the magnetic anisotropy increase. The interesting results of decreasing σʹac, ε′, and tanδ for the composite samples of y = 1 to 4 wt.% to values below the unfilled epoxy sample are explained depending on the dual interface nanolayer model (DINM). Also, based on the DINM, the increase of Tg and dielectric strength for the same samples is interpreted.

Keywords

• Ferrites
• Epoxy
• Nanocomposites
• Dielectric properties
• Impedance spectroscopy