Electromagnetic Properties of Carbon Nanotube/BaFe12−xGaxO19/Epoxy Composites with Random and Oriented Filler Distributions

Abstract

The microwave properties of epoxy composites filled with 30 wt.% of BaFe12–xGaxO19 (0.1 ≤ x ≤ 1.2) and with 1 wt.% of multi-walled carbon nanotubes (CNTs) were investigated in the frequency range 36–55 GHz. A sufficient increase in the microwave shielding efficiency was found for ternary 1 wt.%CNT/30 wt.% BaFe12–xGaxO19/epoxy composites compared with binary 1% CNT/epoxy and 30 wt.% BaFe12–xGaxO19/epoxy due to the complementary contributions of dielectric and magnetic losses. Thus, the addition of only 1 wt.% of CNTs along with 30 wt.% of barium hexaferrite into epoxy resin increased the frequency range where electromagnetic radiation is intensely attenuated. A correlation between the cation Ga3+ concentration in the BaFe12–xGaxO19 filler and amplitude–frequency characteristics of the natural ferromagnetic resonance (NFMR) in 1 wt.%CNT/30 wt.% BaFe12–xGaxO19/epoxy composites was determined. Higher values of the resonance frequency fres (51.8–52.4 GHz) and weaker dependence of fres on the Ga3+ concentration were observed compared with pressed polycrystalline BaFe12–xGaxO19 (fres = 49.6–50.4 GHz). An increase in the NFMR amplitude on the applied magnetic field for both random and aligned 1 wt.% CNT/30 wt.% BaFe12–xGaxO19/epoxy composites was found. The frequency of NFMR was approximately constant in the range of the applied magnetic field, H = 0–5 kOe, for the random 1 wt.% CNT/30 wt.% BaFe12–xGaxO19/epoxy composite, and it slightly increased for the aligned 1 wt.% CNT/30 wt.% BaFe12–xGaxO19/epoxy composite.

Combined Effect of Microstructure, Surface Energy, and Adhesion Force on the Friction of PVA/Ferrite Spinel Nanocomposites

“…One of the primary material science trends is developing composite materials based on a polymer matrix with various fillers [30][31][32][33][34]. Composites often exhibit unexpected behaviors and have properties that differ significantly from those of their components [35][36][37].…”

Microwave Absorption of α-Fe2O3@diatomite Composites

“…It is well known that the combination of different compounds which have excellent microwave properties has led to new composite materials which have earned great technological interest in recent years. The addition of a second phase can significantly improve the electronic properties of the resulting composite materials: Co 0.5 Ni 0.5 Ga 0.01 Gd 0.01 Fe 1.98 O 4 /ZnFe 2 O 4 spinel ferrite nanocomposites [ 7 ] and carbon nanotubes/BaFe 12−x Ga x O 19 /epoxy composites [ 8 ]. There are various types of ferrites based on their crystal structure, including Fe 3 O 4 [ 9 ], gamma-Fe 2 O 3 (γ-Fe 2 O 3 ) [ 10 ], α-Fe 2 O 3 [ 11 ] and so on.…”

Impact of the Nanocarbon on Magnetic and Electrodynamic Properties of the Ferrite/Polymer Composites

“…Today, the development of the functional composites based on magnetic (such as ceramic/ceramic or hard/soft composites [ 1 , 2 , 3 ] and ceramic/polymer composites [ 4 , 5 ]) and carbon (nanotubes, graphite and nanoplatelet) [ 6 , 7 , 8 , 9 , 10 ] nanomaterials attracts great attention due to the fundamental significance and practical importance. The fundamental significance is associated with the violation of the principle of additivity.…”

“…From the practical point of view, these composites can be used for various applications in functional devices as active media [ 2 , 3 , 5 ]. These materials can be used in the field of high-frequency applications such as electromagnetic absorbers [ 1 , 2 , 3 ], antenna technology [ 6 ] and electromagnetic compatibility [ 10 ]. This can be explained by the combination and synergy of the useful properties of the polymer matrix and powdered fillers.…”