Microwave Absorption Of Composites Research Articles

3D-printed conical structure absorber based on NFG/Fe3Si/SiCnw ternary composites for multifunctional integrated electromagnetic microwave absorption

The wave absorbers with dual functions of structural load-bearing and radar absorption have become the solution strategy to cope with the increasingly complex electromagnetic environment. In this paper, a conical structure absorber based on natural flake graphite (NFG)/Fe3Si/SiCnw ternary composites was successfully prepared by selective laser sintering (SLS) 3D printing technique starting from multi-scale design. From the material level, the in-situ grown one-dimensional SiC nanowires effectively improve the dielectric properties of the material, which increases the magnetic/dielectric loss synergy together with the magnetic material Fe3Si. The minimum reflection loss is −54.21 dB and the effective absorption bandwidth (EAB) is 4.6 GHz when the thickness is 1.5 mm. The unit structure of the conical structure absorber was structurally designed and experimentally verified at the structural level, and broadband electromagnetic absorption at 14.45 GHz was achieved and the compressive yield stress was 5.21 MPa. In addition, the EAB of both transverse electric-polarization (TE) and transverse magnetic-polarization (TM) under the variation of incidence angle from 0 to 50° exceeded 12 GHz, indicating that the conical structure absorber has excellent wide-angle absorption properties. The broadband microwave absorption performance of conical structure absorbers is attributed to the synergistic enhancement effect of improved impedance matching on the macroscopic scale and multiple electromagnetic loss mechanisms on the microscopic scale. The conical structure absorber prepared by SLS achieves material-structure-function integration of electromagnetic microwave absorption, and the multifunctional integrated design contributes to the practical application of stealth technology in the field of industrialized electromagnetic microwave absorption.

Rheological investigations on frequency selective surface carbon composite microwave absorber.

A high-performance stealth platform is one of the crucial requirements in defence technology that could practically be realized by building effective microwave frequency selective surface (FSS) absorbers. Herein, we report the design and manufacturing of an absorber by tuning the rheology of cell architecture. Initially, a fan-shaped cell (10.4 mm2) was designed for its surface and bulk rheology. The FSS overlayer composition was investigated using SEM, EDX, and XRD and tuned for 0.25% carbon: 1.5% silver to achieve the ink resistivity ∼255 Ω □-1. The bulk rheology was optimized for air (Roha) spacer (thickness ∼2.8 mm), interlayer dielectrics (0.2 mm each), carbon composition (5%), and cell dimension (10.2 mm). Analyses are presented for absorption loss (RC, dB), bandwidth (GHz), resonance dispersion, and constitutive (ε, μ) parameters, compounded with an equivalent circuit model with the settings R = 273.55 Ω, L = 2.25 nH, C = 0.057 pF and the Fabry-Perot reactance mode@10 GHz. The bi-modal response was investigated for induced polarization, electromagnetic fields, volume power distribution, and angular (Θ = 0°-50°) and rotational stability (Φ = 0°-90°) against TE/TM incidences. The FSS pattern was implemented using a screen printing technique to fabricate a prototype absorber and subjected to the free space measurements in an anechoic chamber. The prototype behaviour was found to be commensurate with the simulated performance, thereby achieving a figure of merit of RC ∼-25 dB@10 GHz, accessible bandwidth 4 GHz (in X band) by using the thickness of 0.057 λ0. Details are presented in this study.

A review on MXene-based microwave absorption composites: engineering, component optimization and structure regulation

This paper classifies MXene-based materials by composition and structure, showing that multicomponent designs and structural modulation enhance absorption. The paper also discusses future directions for MXene MA composites.

Engineering flaky carbonyl iron/MoS2 composites with tuned and broadband absorption towards low-frequency electromagnetic waves

Engineering microwave absorption composites with tuned and broadband absorption towards low-frequency electromagnetic waves of both civil and military areas.

Synthesis BaFe12O19/RGO Composite As Microwave Absorber For Ku-Band

In this study, a composite microwave absorber consist of barium hexaferrite (BaFe12O19) and Reduced Graphene Oxide (RGO) for Ku-band (12-18 GHz) was prosperous blend. Barium hexaferrite to arrange using the sonochemical method and at calcination temperature of 1000°C and a holding time of 1 hour. Subsequently, commercial RGO was composited with barium hexaferrite at a weight percentage of 6% RGO. The synthesized composite was characterized using X-Ray Diffraction (XRD) to analyze the formed phases, Raman Spectroscopy to confirm the presence of RGO in the composite, and Vector Network Analyzer (VNA) to evaluate the microwave absorption performance. The XRD test results show that there is no change in the crystal structure of barium hexaferrite due to the addition of RGO. The VNA test results showed that the addition of RGO could enhance the reflection loss value of barium hexaferrite. The BaFe12O19/RGO compound displayed a reflection loss value of -14.43 dB at a frequence of 16.50 GHz.

Bimetallic MOF@wood-derived hierarchical porous carbon composites for efficient microwave absorption

Biomass-based porous carbon composites have received widespread attention in microwave absorption field due to sustainable sources, unique micro-nano structure, low cost. Nevertheless, it is still a huge challenge to construct biomass-derived microwave absorbers with reasonable structure and multi-component magnetic/dielectric structures in order to satisfy the conditions of advanced electromagnetic wave absorption materials. Herein, CoNi-metal-organic framework (MOF) was grown in-situ on the wood, and CoNi@wood-derived porous carbon composites (WNC) were fabricated by in situ annealing at different temperatures under a nitrogen atmosphere. When the pyrolysis temperature was 700 °C and the loading amount was 30 wt%, the optimal minimum reflection loss of WNC composites could reach −25.96 dB at 17.98 GHz with a thickness of 1.8 mm. The outstanding microwave absorbing capacity is ascribed to the interfacial polarization, conduction loss, dipolar polarization, magnetic loss, and multiple reflections. This research paves a new preparation method for excellent microwave absorption materials.

Design of BCNO@PPy composites for efficient microwave absorption and thermal management

Currently, multifunctional microwave-absorbing materials, especially those with thermal conductivity and microwave absorption functions, have excellent application prospects in electronic packaging. In this study, we first used a sacrificial template method to prepare BCNO using biomass carbon as a template. Then, we used an in-situ synthesis method to grow polypyrrole (PPy) on the surface of BCNO to prepare BCNO@PPy with a core-shell structure. The BCNO@PPy composite exhibits a minimum reflection loss (RLmin) of −52.6 dB at a thickness of only 1.94 mm and an effective absorption bandwidth (EAB) of 5.3 GHz (12.7–18 GHz). The excellent microwave absorption can be attributed to the synergistic effect of polarization loss, conductive loss, and partial magnetic loss in the BCNO@PPy (BPPy) composites, and the multi-wall reflection effect of the core-shell structure, as well as the excellent impedance matching of the composites. Notably, BPPy-3 (polypyrrole content of 28.5 wt%) showed a good thermal conductivity enhancement effect on the epoxy resin (EP) when the content of BPPy-3 was 30 wt%. BPPy-3/EP has a thermal conductivity of 1.82 W(m·K)−1, which is 619.5 % higher than that of pure EP. The good thermal conductivity of the composites is attributed to the excellent compatibility of PPy and epoxy resin, as well as the low interfacial thermal resistance between BCNO and PPy. Therefore, this work can provide a reference for the design of materials with both thermal conductivity and microwave absorption functions.

Fabrication of in-situ Ti-Cx-N1−x phase enhanced porous Si3N4 absorbing composites by gel casting

In view of the lack of a conformal, load-bearing, lightweight, and high-temperature resistant integrated microwave-absorbing composites for applications under extremely complex conditions, this study successfully applies gel casting craft to porous Si3N4 microwave-absorbing composites. The high-temperature decomposition reaction of Ti3SiC2 powder was utilized to generate uniform Ti-Cx-N1−x grains in situ and to enhance the mechanical and microwave-absorption properties of porous Ti-Cx-N1−x/Si3N4 composites. The bending strength, fracture toughness, density, maximum reflection loss value, absorption bandwidth and matched thickness in P-band of the composite with 30 wt% Ti3SiC2 addition were 164.87 ± 7.56 MPa, 2.61 ± 0.13 MPa·m1/2, 2.077 g/cm3, 32.42 dB, 1.74 GHz and 4.2 mm, respectively. The fracture toughness and bending strength of the composite were increased by 71.71% and 58.13%, respectively, compared with monolithic porous Si3N4. The electromagnetic wave loss mechanisms of the composites are proposed as a combination of conductivity loss, multiple reflections and scattering, interfacial polarization and defect polarization.

Fabrication of flexible waterborne polyurethane/Fe-doped residual carbon from coal hydrogasification semi-coke composites for high-performance microwave absorption

Fabrication of flexible waterborne polyurethane/Fe-doped residual carbon from coal hydrogasification semi-coke composites for high-performance microwave absorption

Dense NiCo2 O4 Nanoneedles Grown on Carbon Foam Showing Excellent Electrochemical and Microwave Absorption Properties.

Electromagnetic pollution could harm sensitive electronic equipment due to the rising use of electronic devices and communication infrastructure. The supercapacitor's electrochemical performance should be enhanced, and electromagnetic damage should be prevented. This study proposes NiCo2 O4 /CF composites for supercapacitors and microwave absorption. They are made by combining hydrothermal and annealing processes. Dense NiCo2 O4 nanoneedles were uniformly grown on the outer layer of carbon foam (CF) as a growth skeleton, preventing the agglomeration of NiCo2 O4 . The composite had a specific capacitance of 537.5 F/g at 1 A/g. When the current density was set to 1 A/g, the supercapacitor that used NiCo2 O4 /CF as the cathode had a specific capacitance of 70.7 F/g, and when the current density was increased to 10 A/g, the original specific capacitance of 87.2 % could still be maintained after 5000 charge-discharge cycles. At a power density of 3695.5 W/kg, an energy density of 22.1 Wh/kg could be maintained. Furthermore, we performed a microwave absorption test and determined its reflection loss curve for various sample thicknesses. Recombination enhanced the composite material's microwave absorption capability by greatly reducing the dielectric loss and the magnetic loss.

Nanostructured Carbon-Based Composites for Microwave Absorption: A Review

Nanostructured Carbon-Based Composites for Microwave Absorption: A Review

Construction of one-dimensional hierarchical MoS2/Ni3S2 composites with enhanced interfacial polarization and improved wideband microwave absorption

The construction of one-dimensional (1D) sulfides has attracted extensive attention for improving microwave absorption (MA) performance owing to the anisotropic conductive networks. However, the synthesis of conductive 1D hierarchical materials with unique interfacial polarization and excellent MA properties remains challenging. In this study, cable-like MoS2/Ni3S2 was synthesized by a one-step hydrothermal strategy. The complex permittivity of the binary composites could be improved by tuning the thickness of the MoS2 coating. Importantly, the construction of heterogeneous contacts by MoS2 and Ni3S2 contributed to enhanced polarization loss, and the charge distribution was validated by electron holography. The wide efficient absorption bandwidth can reach above 4.8 GHz at a thin thickness. These new discoveries shed light on novel structures for 1D sulfide materials and the design of functional core-shell composites for microwave absorption.

Fabrication of high-performance LaFeO3/CuCo2O4 nanocomposite for X-band stealth application

The most pressing need for the majority of applications is the development of microwave absorption composites with thin thickness to make them practical to use and capable of high absorption with adjustable effective absorbing bandwidth. In this research, an innovative nanocomposite made of a LaFeO3 compound decorated with CuCo2O4 particles was chemically developed, and its electromagnetic properties were extracted to study microwave absorbing capability using both waveguide and free space methods, as well as related mechanisms. The resin-based absorber sample with 40% LaFeO3/CuCo2O4 nanocomposite possesses the best wave dissipation feature, with a reflection loss of − 20 dB and an absorption bandwidth of 3.3 GHz in an absorber sample with just 1.8 mm thickness. This is due to the best loss capacity matching factor as well as improvements in impedance matching and attenuation coefficient capability. The sample was made on a 20 × 20 cm scale in accordance with the waveguide mode's results, and the findings were completely supported after carrying out the assessments that are required. This study presents a unique approach to developing EMW-absorbing materials with a broad effective absorption bandwidth and an appropriate absorption capacity by assessing the absorption properties using two different testing methodologies.

Novel preparation of FeCo alloy/graphene foam composites for efficient microwave absorption

Five groups of FeCo alloy/graphene foam (FeCo/GF) composites with different GF contents (1%, 2%, 3%, 4%, and 5% of the mass of the FeCo alloy) were prepared in this work. The results show that the morphology, saturation magnetization, and electromagnetic parameters of the composites were greatly affected by the GF amount. The reticular porous structure of GF significantly increases the multiple scattering events and loss paths of electromagnetic waves and provides an excellent electric loss. Being a typical soft magnetic material, FeCo exhibits a high saturation magnetization and an excellent magnetic loss. The FeCo/GF composite has excellent microwave absorption properties, which are attributed to its superior dielectric loss, conductive loss, natural resonance, and exchange resonance loss mechanisms. In particular, when the content of GF is 3% of the mass of FeCo alloy, it exhibits the best effective absorption bandwidth. With a matching thickness of only 1.85 mm, this composite achieves a maximum effective absorption bandwidth of 7.2 GHz (10.8–18 GHz). Additionally, when the content of GF is 4% of the mass of FeCo alloy, the sample exhibits the lowest reflection loss, which reaches −61.68 dB at a frequency of 3.44 GHz.

Multi-morphology composite: Particle & petal-shaped ZnFe2O4/flower-shaped ZnO@Porous biomass carbon with excellent broadband microwave absorption performance

Utilizing carbon and magnetic components to construct microwave-absorbing composites with broadband and strong absorption has become a research focus. Improving the structural coupling of these materials to enhance impedance matching and dielectric performance remains a significant obstacle. Particle and petal-shaped ZnFe2O4/flower-shaped ZnO@chestnut shell biomass-carbon composites (ZnFe2O4/ZnO@CBC) were synthesized via a one-step sintering method. The biomass carbon-based material presents a three-dimensional framework structure, while the particle and petal-shaped ZnFe2O4 and flower-shaped ZnO are uniformly distributed on its surface. This distribution significantly improves the dielectric polarization performance and magnetic loss of the material, ultimately leading to good microwave attenuation ability through impedance matching. Taking the addition of 1 g of biomass as an example, the minimum reflection loss (RLmin) of the composite material is −50.43 dB, and the widest effective absorption bandwidth (EAB) reaches 7.13 GHz (10.87–18 GHz). Notably, the EAB of the different composite materials all remains above 6.4 GHz when the biomass addition is adjusted within the range of 1–2.5 g, indicating that they are not sensitive to the amount of biomass used and have good stability in microwave absorption performance. Moreover, the results of the simulation and modeling analyses of the radar cross section (RCS) further validate the efficacy of composite materials in attenuating microwaves. These results offer valuable insights into the stability of bandwidth in materials and the potential application of biomass in wave-absorbing materials. It also shows that the composites are highly promising and reliable candidates for microwave absorption applications due to their high-performance, wide-band, and thin-absorption properties.

Excellent electrically insulated, thermal-oxidation resistant and corrosion resistant flaky-FeSiAl/BN core–shell composites for high-performance microwave absorption in harsh environments

Currently, multifunctional microwave absorption (MA) materials have become increasingly important in addressing the serious issue of electromagnetic pollution. In this study, flaky FeSiAl (FFSA)/hexagonal boron nitride (h-BN) composites with a core–shell structure were prepared by plasma-assisted ball milling. The FFSA9BN1 composite, with a mass ratio of 9:1 (FFSA:h-BN), exhibits a minimum reflection loss (RLmin) of −68.18 dB at a thickness of 2.14 mm, because the h-BN shells improve the impedance matching of the composites and produce abundant polarization loss. Additionally, the MA performance of the composites hardly shows a decline even after a thermal oxidation at 500 °C for 12 h due to the dense h-BN shells as oxygen barriers. Simultaneously, the corrosion rate of the FFSA/h-BN composites is 66.5% less than that of the FeSiAl cores. Consequently, plasma-assisted ball milling provides a facile and eco-friendly technology to prepare multifunctional FFSA/h-BN core–shell composites for diverse applications in some extreme environments.

3D printing of carbon black/polylactic acid/polyurethane composites for efficient microwave absorption

3D printing of carbon black/polylactic acid/polyurethane composites for efficient microwave absorption

One-dimensional core–shell CoC@CoFe/C@PPy composites for high-efficiency microwave absorption

In recent years, electromagnetic pollution has become more and more serious, and there is an urgent need for microwave absorbing materials with superior performance. Prussian blue analogue (PBA) is a metal organic framework material with the advantages of diverse morphology and tunable composition. Therefore, PBA has attracted a lot of attention in the field of microwave absorption. In this work, PBA was coated on the surface of carbon composites by hydrothermal method, and then PPy was compounded on its surface after carbonization treatment to construct hierarchical core–shell CoC@CoFe/C@PPy fibers. The fibers have Co-doped C composites as the core and CoFe/C decorated with PPy as the shell. This unique hierarchical structure and various microwave absorption mechanisms are described in detail. The microwave absorption performance is optimized by adjusting the filling of the sample. The best microwave absorption performances are achieved at 25 wt% filling of CoC@CoFe/C@PPy. At a thickness of just 1.69 mm, CoC@CoFe/C@PPy fiebrs have a minimum reflection loss (RLmin) of −64.32 dB. When the thickness is 1.88 mm, CoC@CoFe/C@PPy achieves a maximum effective absorption bandwidth (EABmax) of 5.38 GHz. The results indicate that the CoC@CoFe/C@PPy composite fibers have a great potential in the field of microwave absorption.

Electromagnetic response of grading honeycomb composites for broadband microwave absorption

The fundamental challenge for microwave-absorbing honeycomb composites with grading coating thickness is the unsatisfactory absorption bandwidth. In this work, an effective equivalent permittivity prediction model was established based on the homogenization method, also both the result of calculations and simulation exhibit good consistency which indicates the validity of the model. Furthermore, in-depth analysis was done on the impact of structural factors like honeycomb height and coating thickness on single layer microwave absorption. Finally, both the microwave absorption properties and the electromagnetic response of grading honeycomb microwave absorbing composites were investigated which show a bright future in reducing electromagnetic wave irradiation and interference. The present work could provide a powerful theoretical basis for designing advanced grading honeycomb microwave absorbing composites.

Absorber design based on In/C@Co/C composites for efficient microwave absorption

Due to increasing electromagnetic pollution, excellent microwave absorption materials (MAMs) are extremely desired in our daily life. In this work, MOF-derived prism-like core-shell structured In/C@Co/C-x (x = 700, 800 and 900) composites were prepared by using a simple pyrolysis approach. The unique hierarchical structure with evenly-distributed Co-nanoparticle magnetic shell covering porous In/C core renders the composites remarkable microwave absorption performance. The In/C@Co/C-800 shows a minimum reflection loss (RLmin) of − 55.14 dB with a broad effective absorption bandwidth (EAB) of 5.12 GHz at 2.19 mm. Moreover, a series of periodic stepped microwave absorption structures based on In/C@Co/C-800 are designed using HFSS to perform the broadband microwave absorption. The EAB of a four-layer periodic stepped structure reaches 15.28 GHz, covering 0.955 of the frequency range. This work demonstrates that a nanoparticle magnetic shell composite of In/C@Co/C achieves efficient microwave absorptions, and proposes a structural design strategy for broadband absorption.