Microwave Absorption Of Composites Research Articles

Improved polarization loss and impedance matching induced by carbon paper-based magnetic heterostructured composites for lightweight and strong microwave absorption

Improved polarization loss and impedance matching induced by carbon paper-based magnetic heterostructured composites for lightweight and strong microwave absorption

Design and performance of 3D-Printed ABS@rGO/CF/CeO2 composites for microwave absorption and mechanical strength

Traditional microwave absorbing materials struggle to balance wideband absorption with mechanical properties, particularly in multifunctional applications. This study explores the effects of short carbon fibers (CF), cerium dioxide (CeO2), and reduced graphene oxide (rGO) on the electromagnetic and mechanical properties of 3D-printed composites. The ABS@CF/CeO2/rGO composite with a thickness of 2.2 mm exhibited exceptional microwave absorption, achieving an effective absorption bandwidth (EAB) of 6.6 GHz and a minimum reflection loss (RLmin) of −40.9 dB. The Whale Optimization Algorithm (WOA) was employed to design a load-bearing, microwave-absorbing superstructure, which significantly improved wideband absorption. Experimental results confirmed the superstructure’s isotropy and wide-angle absorption capabilities. The calculated electromagnetic parameters were applied to evaluate the radar cross-section (RCS) of large targets, demonstrating enhanced stealth performance for unmanned aerial vehicles (UAVs). Mechanical tests revealed that rGO improved interlayer bonding strength, while CF negatively impacted bending performance. The superstructure also showed excellent mechanical stability in load-bearing tests, underscoring its potential for practical engineering applications. This study offers insights into designing advanced composite materials with balanced electromagnetic and mechanical properties, guiding future multifunctional material development.

One-step pyrolysis derived Fe and heteroatom co-doped biochar composites for efficient microwave absorption

Electromagnetic (EM) pollution frequently disrupts the regular operation of sophisticated electrical devices, necessitating the urgent development of lightweight EM wave absorbers that possess powerful absorption capability. Herein, we report a simple method for the preparation of Fe and heteroatom co-doped biochar composites (FeX-BC, where X = N, S) by directly carbonizing the precursors of anhydrous FeCl3, cherry kernel powder, and heteroatom dopants (melamine or Na2S2O3·5H2O). By adding different amounts of dopants during the synthesis of the precursors, it is possible to adjust the heteroatom content of the FeX-BC samples with precision. It is worth mentioning that the FeN0.1-BC composite delivers the best EM wave absorption performance with an effective absorption bandwidth of 4.8 GHz and a minimal reflection loss of −63.2 dB. Furthermore, the significant attenuation of EM wave can be attributed to the synergistic interplay of magnetic loss, dielectric loss and the enhanced impedance matching. This study introduces a simple methodology for the fabrication of EM wave absorbers, a significant contribution to the synthesis, advancement, and functional applications of biomass-derived materials.

Self-Templating Engineering of Hollow N-Doped Carbon Microspheres Anchored with Ternary FeCoNi Alloys for Low-Frequency Microwave Absorption.

Rational design and precision fabrication of magnetic-dielectric composites have significant application potential for microwave absorption in the low-frequency range of 2-8GHz. However, the composition and structure engineering of these composites in regulating their magnetic-dielectric balance to achieve high-performance low-frequency microwave absorption remains challenging. Herein, a self-templating engineering strategy is proposed to fabricate hollow N-doped carbon microspheres anchored with ternary FeCoNi alloys. The high-temperature pyrolysis of FeCoNi alloy precursors creates core-shell FeCoNi alloy-graphitic carbon nano-units that are confined in carbon shells. Moreover, the anchored FeCoNi alloys play a critical role in maintaining hollow structural stability. In conjunction with the additional contribution of multiple heterogeneous interfaces, graphitization, and N doping to the regulation of electromagnetic parameters, hollow FeCoNi@NCMs exhibit a minimum reflection loss (RLmin) of -53.5dB and an effective absorption bandwidth (EAB) of 2.48GHz in the low-frequency range of 2-8GHz. Furthermore, a filler loading of 20wt% can also be used to achieve a broader EAB of 5.34GHz with a matching thickness of 1.7mm. In brief, this work opens up new avenues for the self-templating engineering of magnetic-dielectric composites for low-frequency microwave absorption.

Combined design of dielectric material and layer structure of vanadium nitride/graphene composites for ultra-broadband microwave absorption

Combined design of dielectric material and layer structure of vanadium nitride/graphene composites for ultra-broadband microwave absorption

Facile constructing core-shell F–CIP@O/N-SWCNHs composites for high-performance microwave absorption and anti-corrosion

The development of electromagnetic wave-absorbing materials (EWAMs) with good environmental adaptability has emerged as a focal point of research in the realm of electromagnetic protection. Herein, a core-shell structure composite EWAMs, in which flake carbonyl iron powders and O, N co-doped single-walled carbon nanohorns are respectively a core and a shell (F–CIP@O/N-SWCNHs), has been prepared by a simple electrostatic adsorption method. The high-shape anisotropy of the F–CIP core exhibits strong specific saturation magnetization (160.47 emu/g) and excellent magnetic loss capacity. The tunable O/N-SWCNHs shell effectively enhances the dielectric properties and improves impedance matching, while the oxygen and nitrogen doping strengthens the dipole polarization. The surface protection provided by O/N-SWCNHs imparts favorable corrosion resistance and anti-oxidation properties to the F-CIP@O/N-SWCNHs. Moreover, F–CIP@O/N-SWCNHs exhibit excellent wave absorption performance. When the sample thickness is 1.53 mm, the minimum reflection loss reaches −74.8 dB. This study provides a feasible approach for the preparation of efficient EWAMs with strong environmental adaptability for the practical application of composite-absorbing materials.

Fabrication of MXene-encapsulated Co@C nanoparticles for efficient microwave absorption in the X-band

Two-dimensional MXene has structural advantages in electromagnetic wave scattering due to its layered structure, but MXene materials can lead to impedance mismatch problems due to their high dielectric constants, so it is still a challenge to design highly efficient wave-absorbing materials based on MXene with low reflection loss, thin thickness, and wide absorption frequency. In this study, composite wave-absorbing materials were fabricated from Co–Co PBA precursors and MXene using liquid nitrogen flash freezing and freeze-drying techniques. By treating MXene and the PBA precursor at a high temperature of 750 °C, a rich heterogeneous interface was formed between Co@C and MXene (CCM7), and the impedance matching was optimized to improve the reflection loss capability. The optimized sample has an effective absorption bandwidth of 4.1 GHz at 2.5 mm covering the entire X-band with a minimum reflection loss of −61.42 dB. It is also demonstrated that CCM7 is satisfactory for Radar Cross-Section of flat panels and unmanned aerial vehicles by CST calculations, and this work provides a fresh perspective on the use of effective MXene composites for microwave absorption.

Fe3C/Fe implanted hierarchical porous carbon as efficient electromagnetic wave absorber

The rapid development of communication technology has led to severe microwave pollution, which presents a challenge for microwave-absorbing composites. Current research suggests achieving superior microwave absorption requires the use of multi-component operation and ingenious structural design. Consequently, the present study has prepared continuous porous carbon (CPC) materials doped with large amounts of Fe3C/Fe nanoparticles (Fe@CPC) using carbonization and acid etching. By balancing the advantages of the above strategies, it is possible to address issues such as poor impedance match, single loss capacity, easy oxidation of magnetic metals/alloys, and the limited absorption bandwidth of conventional absorbing materials at the same time. The material exhibits a minimum reflection loss of −23.2 dB with an efficient absorption range of 5.3 GHz at 1.9 mm at a filler content of just 10 wt% in the paraffin matrix. In this paper, the samples with a continuous porous structure were prepared by a simple method, and the properties were excellent due to the appropriate preparation method and the synergistic effect of the multi-component composite. The porous structure facilitates the presence of a considerable number of active sites, which enables the loading of a substantial quantity of metal ions. Furthermore, nanoparticles are capable of aggregating and dispersing on the surface. This paper presents a theoretical framework for understanding the synergistic effect of microwave radiation through interfacial polarization and micro-scale magnetic interaction. Nevertheless, there are still obstacles to overcome in terms of achieving precise control over the structural design and ensuring the compatible integration of metal components.

Study on Structure-Function Integrated Polymer-Based Microwave-Absorption Composites.

This article provides an in-depth exploration of the current state of research in microwave-absorbing composite materials, juxtaposing the status quo of coating type and structurally reinforced resin-based composites, with a particular emphasis on the latter's structural and performance superiority. It succinctly elucidates the mechanisms of electromagnetic shielding, as well as the conditions and underlying principles that govern the absorption of microwaves by composite materials. The review continues by dissecting the strategies for enhancing the microwave-absorption capabilities of resin-based composites, including the classification of absorbents, absorbent selection, and an overview of structural design innovations in microwave-absorbing materials. Structural wave-absorbing composites are manufactured by combining different types of resin matrices, absorbers, reinforcing fibers and construction methods. The interactions between these components are scrutinized to reveal how each contributes to the overall performance of the composite. We spotlight the unique construction methods and the intricate relationship between structure and performance in structurally reinforced composites, offering insights into the optimization strategies for composite-material absorption characteristics. Concluding with a forward-looking perspective, the article contemplates the burgeoning potential and future applications of fiber-reinforced resin-based microwave-absorbing composites, setting the stage for a new era in material science and technology.

Pomb@Co3O4-based composites for ultra-wideband microwave absorption: A multi-scale perspective from micro-, meso- and meta-structure

Microwave absorbing materials (MAMs) are used to prevent electromagnetic pollution and enhance equipment stealth. However, their limited absorption intensity and narrow effective bandwidth restrict their applicability. MAMs with a single absorption mechanism, whether dielectric or magnetic, often exhibit poor impedance matching. This paper introduces a new multiscale approach—encompassing microstructures, mesostructures and macrostructures—for designing high-performance MAMs. At the microscopic–mesoscopic level, Pomb materials derived from pomegranate peel are combined with magnetic nanoparticles (Co3O4) using a hydrothermal method. The microwave absorption properties of these composite materials were examined by varying the proportion of Pomb materials in the absorber. The effective absorption bandwidth (EAB) reached 5.5 GHz for a thickness of 2.3 mm. At the macroscopic level, a metastructure based on Pomb@Co3O4 (0.1 g) was designed to achieve ultrabroadband absorption with an EAB of 15.56 GHz, a range of 2.24–18 GHz and a total thickness of 15 mm. Additionally, the radar cross-section value of Pomb@Co3O4 (0.1 g) is below − 10 dB m2 across the angle range of − 60° to 60°, with a maximum scattering intensity of only − 7.6 dB m2. This multiscale structure design offers a promising direction for future research and development in MAMs.

Heterointerface-engineered SnO2@SnO nanoparticle@foamed C composites for prominent microwave absorption and thermal conduction performance

The development of multifunctional materials with wide-band microwave absorption properties (MWAPs), high thermal conductivity (TC), and excellent electrical isolation is rather challenging due to the performance incompatibility. To resolve this challenge, SnO2@SnO nanoparticle(NP)@foamed C composites are synthesized as an electrically insulated filler with low loads, excellent MWAPs, and high TC via a facile salt-template-assisted freeze-drying-annealing route. By controlling the annealing temperature (Ta) and the amount of SnCl2·2H2O (n), their heterointerfaces, textures, and defects were finely modulated. Our results show that the SnO2@SnO NP@foamed C composites have a large TC (3.48 W/(m·K); 1.5 wt% load), a minimal reflection loss (RLmin) of −40.75 dB, and an effective absorption bandwidth (EAB) of 6.88 GHz at a low load of 25 wt%. The composites exhibit an 8.0 % increase in TC, a 9.4 % increase in EAB, and an 11.0 % increase in RLmin compared with pure foamed C. Besides, the mechanism of dielectric loss and thermal transfer at the atomic level was revealed by the calculations of the density of states (DOS) and the phonon density of states (PDOS). The boosted MWAPs could be ascribed to the breakdown of local microstructural symmetry and the formation of extra electric dipoles at the interfaces of SnO/C, SnO/SnO2, and SnO2/C. The improved TC mainly results from the combined effect of the low-energy phonons from SnOx and the high-energy phonons from C. This study provides theoretical guidance for designing integrated materials with effective microwave absorption and thermal conduction in the electronic industry.

Designing Symmetric Gradient Honeycomb Structures with Carbon-Coated Iron-Based Composites for High-Efficiency Microwave Absorption

HighlightsMIL-88C (Fe) with varying aspect ratios as a precursor was synthesized by regulating oil bath conditions, followed by one-step thermal decomposition to obtain carbon-coated iron-based composites.High-efficiency microwave absorption properties were achieved with RLmin value of -67.4 dB (2.13 mm) and wide effective absorption bandwidth (EAB) of 5.52 GHz (1.90 mm) under the low filler loading.A symmetric gradient honeycomb structure was constructed utilizing the high-frequency structure simulator, achieving an EAB of 14.6 GHz and a RLmin of -59.0 dB.

Polypyrrole modified MIL-101-Fe-derived Fe/Fe3O4@C composites for high-performance microwave absorber

Carbon-based microwave absorbing composites with magnetic-dielectric properties and multiple loss mechanism are considered to be an effective choice for solving electromagnetic pollution. In this paper, the PPy/Fe/Fe3O4@C composite was synthesized from MIL-101-Fe derivatives and subsequently coated polypyrrole (PPy) by combining hydrothermal, high-temperature pyrolysis and oxidative polymerization. The effects of pyrolysis temperature and PPy loading on components, microstructures and electromagnetic parameters were investigated. The results showed that the PPy/Fe/Fe3O4@C composite consisted of two-dimensional carbon flakes modified by magnetic particles and laminated conductive polymers. When the PPy loading is moderate, the composite reaches a minimum reflection loss (RLmin) of −61.38 dB at a 3.1 mm thickness and effective absorption bandwidth (EAB) of 5.81 GHz at the thickness of 2.2 mm. After pyrolysis, the unique three-dimensional structure of carbon sheet stacking, as well as the heterogeneous interface and conductive networks generated by the modification of magnetic particles Fe and Fe3O4 and conductive PPy, are beneficial to improve the dielectric and magnetic losses to optimize the impedance matching. These conductive polymer-modified magnetic-dielectric composites have potential for development and application in microwave absorption.

Lightweight and robust electrospun zirconia fiber reinforced carbon aerogel composites for efficient microwave absorption and heat insulation

Carbon aerogel (CA) is recognized as a promising microwave absorption (MA) material, but it remains greatly challenging to integrate the multiple functions of MA, mechanical strength, and heat insulation. In this work, a novel zirconia fiber reinforced CA (ZF/CA) composite is successfully fabricated via electrospinning technology coupled with a sol-gel impregnation process for the first time. The density (0.132–0.206 g/cm3) of the obtained ZF/CA composites can be regulated by simply varying the initial sol concentration, thus effectively tuning their performance. Notably, the ZF/CA composites display excellent MA properties, with a strong absorption of −80.30 dB at the thickness of merely 1.71 mm and the optimal effective absorption bandwidth reaches 5.16 GHz, which is a significant improvement compared to CA (−11.70 dB, 0.58 GHz). Simultaneously, the brittleness and cracking problems of CA are effectively addressed by the soft reinforcement strategy of electrospun zirconia fibers, and superior mechanical strength is obtained. Furthermore, the nanopore structure and hierarchical design endow the ZF/CA composites with low thermal conductivity (0.029–0.038 W m−1 K−1) and favorable heat insulation performance. Outstanding MA capacity and excellent heat insulation properties along with lightweight construction and high strength make ZF/CA composites a great candidate for efficient MA and heat insulation.

Glucose derived carbon encapsulated boron nitride core-shell composites for efficient electromagnetic microwave absorption

Hexagonal boron nitride (h-BN) has the advantages of outstanding insulation, high thermal conductivity and excellent chemical stability, which promote the wide application of h-BN in thermal interface electronic packaging and other related fields. However, due to the poor dielectric loss ability of h-BN, which leads to its weak absorption capacity of electromagnetic waves (EMW), so it limits its practical application in related advantageous fields. In this paper, glucose-derived carbon-encapsulated BN core-shell composites (C@BN) were prepared by a simple hydrothermal reaction followed by high-temperature pyrolysis. The dielectric loss capacity of the C@BN was investigated by manipulating the concentration of glucose solution and pyrolysis temperature. Specifically, by adjusting the glucose derived carbon defect to induce polarization loss and impedance matching performance, so that more EMW entering the interior of the composite is absorbed and dissipated. The results show that C@BN obtained at 800 °C shows the best EMW absorption performance when the concentration of glucose solution is 3.6 wt%. The minimum reflection loss value (RLmin) is −43.5 dB and the maximum width effective absorption bandwidth (EABmax) of 6.72 GHz. Therefore, this study provides a reliable reference for the preparation of h-BN based EMW absorbing materials.

MXene/cobalt ferrite/carbon materials based composites for efficient microwave absorption

In the present study, cobalt ferrite (CF) nanoparticles were in-situ grown on MXene/carbon-based materials (activated carbon (AC), MWCNT, and GO) to develop composites via facile hydrothermal route. The MXene/CF/MWCNTs composite (FMCNT4) achieved an excellent maximum reflection loss (RLmax) of −67.04 dB at 16.24 GHz & a thickness of 5.94 mm, whereas at the thickness of 5.86 mm, the FMCNT4 obtained a maximum effective absorption bandwidth (EAB, RL < −10 dB) of 2.73 GHz. On the other hand, replacing MWCNTs with AC in the composite (FMAC4) showed RLmax of −46.52 dB at 18 GHz and 5.1 mm thickness, it also got an EAB of 2.54 GHz at 5.5 mm thickness. The MXene/CF/GO composite (FMGO5) obtained RLmax = −17.31 @ 17.12 GHz & 6 mm. The composite having MWCNTs showed the best performance, and the reason for this remarkable MW absorption performance originated from the high impedance matching followed by dielectric polarization and magnetic losses in the composite. The formation of multiple heterointerfaces between MXene, CF, and MWCNTs enhanced the interfacial polarization, whereas the conducting MXene and MWCNTs also contributed to conduction polarization. Thus, the present investigation showcases FMCNT as an excellent synergetic nanocomposite for MW absorption applications.

Biomimetic artificial nacre-like microfiber of Co/C modified cellulose nanofiber/Ti3C2Tx MXene with efficient microwave absorption

Although considerable efforts have been made in the fabrication of MXene-based composites for microwave absorption (MA), there is a great challenge to assemble MXene into regularly arranged microfibers prepared by wet-spinning technique for application in the field of MA due to insufficient interlayer interactions between Ti3C2Tx flakes. Heterogeneous interface design by optimizing material components to construct ingenious microstructure is crucial for efficient microwave absorbers. Herein, artificial nacre-like supramolecular microfibers of Co/C modified cellulose nanofiber/Ti3C2Tx MXene (Co/C/CNF/Ti3C2Tx) with plenty of heterogeneous interfaces were prepared by a simple wet-spinning technology through a self-assembly process induced by hydrogen bonding interactions between CNF and Ti3C2Tx. The artificial nacre-like microfibers with layered structure possess abundant heterogeneous interfaces, which facilitate multiple reflections/scattering of electromagnetic waves (EMW) between these interfaces, and at the same time promote interfacial and dipole polarization. The introduction of magnetic Co/C nanoparticles not only offer additional magnetic loss ability and improved impedance matching, but also enhance conductivity loss and polarization loss. Benefiting from these advantages, Co/C/CNF/Ti3C2Tx (1:1:1) fiber exhibits superior MA performance with a minimum reflection loss (RLmin) of up to −62.32 dB (>99.9999 % energy absorption) and a broad effective absorption bandwidth (EAB) of 5.86 GHz. The work provides a promising method for the preparation of biomimetic artificial nacre-like MXene-based microfibers with efficient MA performance, which is expected to be applied in the field of flexible wearable electromagnetic protection.

Improving RFID performance through enhanced electromagnetic wave absorption with Fe2O3 and polytetrafluoroethylene-based bilayer polydimethylsiloxane composites

This study presents a bilayer polydimethylsiloxane (PDMS) composite microwave absorber, consisting of Fe2O3 and polytetrafluoroethylene (PTFE) fillers, to enhance the functioning of radio frequency identification (RFID) systems on conductive surfaces. The uniform Fe2O3/PDMS and PTFE/PDMS composites are prepared by mixing PDMS and respective filler through a desktop three-axis roller machine followed by curing at 80 °C for two hours. The composites are then joined to create a bilayer composite mat. The combination of a 70 wt% Fe2O3/PDMS composite with a 50 wt% PTFE/PDMS composite demonstrates the best performance. The Fe2O3/PDMS composite shows the high reflection loss of 47.98 dB and a total shielding of 4.1 dB, while the PTFE/PDMS composite exhibits the reflection loss of 47.0 dB and a total shielding of 0.6 dB. The optimized bilayer composite enables a tag recovery of approximately 87.57 %. These findings demonstrate its practical application in reducing interference and enhancing the RFID tag detection.

Study on Properties of Glass-Fiber-Fabric-Reinforced Microwave-Absorbing Composites.

In this paper, the glass-fiber-fabric-reinforced resin-based absorbing composites were prepared, and their microwave-absorbing properties were studied via simulation and experiment. The simulation results show that the absorption bandwidth of the absorbing material can cover the X\C\S band, respectively, at different thicknesses. The minimum reflection loss (RL) of the composite with a thickness of 2.2 mm is -27.4 dB at 5.95 GHz. However, the experiment results are quite different from those of the simulation. The metallographic results indicate that it is the change of the mass fraction of the absorbents in the composites after curing that causes the difference. According to the metallographic results, three shape approximation methods were proposed to calculate the real mass ratio of the absorbents in the composites, namely, parallelogram approximation, bows approximation, and elliptical approximation. Meanwhile, the structural parameter Kf was introduced to optimize the calculation results. The electromagnetic parameters of the material based on the calculation results were measured, and the results show that the simulation results obtained via bow approximation have a better coincidence to the experiment results, and the mass ratio of the absorbent raises by around 9.95%, which lays a foundation for the subsequent design of microwave-absorbing composites.

Prussian blue analogue-derived ZnOCo@nitrogen-depleted g-C3N4(ND-CN) for lightweight and efficient electromagnetic wave absorption

The sustainable electromagnetic (EM) environment urgently needs the development of high-performance absorbers. This study involved synthesizing a series of ZnOCo@ND-CN (X) composites through in-situ depositing Prussian blue analogue (Zn3[Co(CN)6]2) on varying amounts of Nitrogen-Depleted g-C3N4 (ND-CN), followed by carbonization. Adjusting the amount of ND-CN in the composites can effectively regulate the dielectric constant. The as-fabricated defective structures with high electrical conductivity and the synergy between ND-CN with ZnOCo particles, as well as the presence of a variety of heterogeneous interfaces, which endow the composites with the impressive EM wave absorption properties. ZnOCo@ND-CN (0.2) simultaneously exhibits a minimum reflection loss value of −51.57 dB and a widest effective absorption bandwidth of 5.70 GHz at the thickness of only 1.7 mm with merely 8 wt% filler. This work provides a scalable strategy for the construction of multicomponent PBA-derived composites for lightweight and high-performance microwave absorption.