Microwave Absorption Performance Research Articles

Monolayer Interfacial Assembly toward Two‐Dimensional Mesoporous Heterostructure for Boosting Wave Absorption

AbstractMicrowave absorption materials play a key role in various fields, including military stealth, human safety protection, and so on. Construction of 2D mesoporous heterostructures is an attractive approach to enhance wave‐absorbing ability, while it is still a great challenge. Herein, 2D mesoporous carbon‐MXene‐carbon heterostructures (MCMCH) with channels parallel to surface are successfully prepared via a monolayer interfacial assembly strategy. Through the precise adjustment and polymerization, cylindrical micelles orderly monolayered assemble on both surfaces of 2D MXene nanosheets, resulting in 2D switch‐like polydopamine‐MXene‐polydopamine nanosheets, and 2D MCMCH are finally generated by further calcination. Due to the excellent dielectric polarization relaxation and conductive loss, MCMCH achieves the strongest reflection loss of −54.2 dB at a thickness of only 1.5 mm. The presence of mesochannels not only introduces air with a low permittivity for optimal impedance matching, but also further extends the attenuation path of the incident electromagnetic wave. The maximum radar cross‐section reduction of 26.9 dB m2 is achieved for the MCMCH compared to the perfect electric conductor. This work provides a reference for surface engineering based on 2D mesoporous heterostructures to enhance the microwave absorption performance.

PVP-assisted MOF-derived Fe3O4/C powders for microwave absorption applications.

Metal-organic framework (MOF) derived porous Fe3O4/C powders were applied for absorption of microwaves in the frequency range of 1-18GHz. The effects of the polyvinylpyrrolidone (PVP) additive on the synthesis of MIL101-(Fe) precursor were studied by various characterization methods. By adding PVP, the impure hematite phase (α-Fe2O3) with magnetite phase (Fe3O4) was disappeared and the particular morphology was transformed to the porous rod-like, leading to the increase of specific surface area from 150 to 282m2/g. Furthermore, the saturation magnetization (Ms) of Fe3O4/C powders reached a maximum value of 47 emu/g at a proper amount of PVP. A thin absorber (2.6mm) made of 50wt% Fe3O4/C powders and 50wt % paraffine absorbed the whole of X frequency band (8-12GHz) with a minimum reflection loss of -20 dB at a matching frequency of 10GHz. Adjusting the permittivity and permeability parameters of the Fe3O4/C powders via adding PVP was responsible for their better microwave absorption performance.

Bio-derived graphitic carbon microspheres: A green approach for high-frequency microwave absorption

Bio-derived carbon materials have emerged as a sustainable alternative to non-renewable petroleum-based carbon sources, thanks to their reproducibility and environmental benefits. There is a strong demand for developing and efficiently utilizing carbon-based microwave absorbing materials (MAMs) that are lightweight, require low filler loading, and offer broadband absorption for electromagnetic wave (EM) applications. In this context, we successfully synthesized uniform carbon microspheres from the natural precursor turpentine oil using the chemical vapor deposition (CVD) technique at various temperatures. The sample prepared at 1000 °C (GC-1000) exhibited a uniform carbon microsphere morphology, as confirmed by XRD and Raman spectroscopy, and demonstrated extremely good microwave absorption properties. With a low filler loading of just 5 wt%, the GC-1000 sample achieved a minimum reflection loss (RL) of −39.77 dB at 10.21 GHz and an effective absorption bandwidth of 2.51 GHz at a matching thickness of only 2.8 mm. Additionally, this sample showed a total shielding effectiveness (SET) of −44.74 dB, surpassing the threshold required for commercial applications. The graphitic phase formation, confirmed by XRD and Raman analysis, acts as a conductive trap for electromagnetic radiation, and the high surface area of the uniform carbon microspheres facilitates multiple internal reflections, enhancing overall microwave absorption performance in the X-band region. Our lightweight, durable, bioderived carbon microspheres, synthesized through a cost-effective and scalable process, show significant potential for EM wave absorption in military and electromagnetic compatibility (EMC) devices.

Preparation and performance of porous carbon microwave absorber with high porosity from carbonized natural plant fibers

Herein, we present a novel fabrication approach to synthesize lightweight, highly porous, high-frequency microwave absorbers via temperature-induced manufacturing of 1D helical/chiral porous carbon fibers (HPCFs). This approach is unmatched in its effectiveness. Furthermore, this unique fabrication approach does not require pre-treatments such as activation, complex stripping-off processes, or harmful chemicals to generate the microwave absorber (MA). The MA with nanoscale/microscale structures, multidimensional 0 or 1D integration, helical/chiral configuration, and assorted loss mechanisms endow the absorber with exemplary microwave absorption capabilities. The maximum reflection loss (RLmax) of HPCFs-700-22.5% (700 and 22.5% correspond to the temperature at which biomass fiber get carbonized and the amount of filler material present) achieves -57.40dB RLmax at 15.20GHz with the wide effective absorbing bandwidth (EAB, RLmax ≤ -10 dB) of 5.40GHz (12.60-18.00GHz) and 2.47mm thickness. Notably, at a matching thickness of 2.60mm, the EAB improved to cover 12.00-18.00GHz (6.00GHz). Moreover, HPCFs-800-22.5 exhibit ultrawide EAB covers of 14.60-18.00GHz (3.40GHz), while RLmax surpasses -57.80dB at the matching thickness of 1.51mm. HPCFs-900-22.5% achieve RLmax of just -51.00dB with EAB of 5.40GHz (12.60-18.00GHz) at 14.90GHz, while the matching thickness of absorber is 2.22mm. The HPCFs with such exceptional microwave absorption properties shed light on the development economical and environmentally friendly MA with comparable microwave performances over exceptional EAB.

Hollow conductive polypyrrole microtubes as microwave absorbents with good seawater corrosion resistance

Conductive polymers materials with hollow micro/nanostructure due to their special electrical properties and corrosion resistance have potential applications in microwave absorption, especially in marine environment. Herein, one-dimensional hollow conductive polypyrrole microtubes (H-PPyM) were prepared by in-situ polymerization of pyrrole monomer with methyl orange (MO) as soft template and FeCl3 as oxidant based on structural regulation strategy. The morphology and conductivity of H-PPyM can be easily controlled by adjusting the content proportion of MO. The results indicated that the surface morphology of polypyrrole changed from random granular to microtubular and the conductivity also gradually rose with the content increase of MO. When the content proportion of MO was 0.25 g, the obtained H-PPyM-0.25 composites possed notable microwave absorption capacity, simultaneously achieving ultrabroad effective absorption bandwidth (EAB, 6.7 GHz) and strong reflection loss value (RL, -33.6 dB) at a thickness of 2.6 mm with the filling content of only 10 wt.%, respectively. Furthermore, the corresponding H-PPyM-0.25 products soaked in corrosive medium (3.5 wt% NaCl solution) for one month still displayed stable tubular hollow structure and excellent microwave absorption performance with RLmin of -43.8 dB and EAB of 6.2 GHz. The research results can not only help to understand the relationship among the morphology and microwave absorption of PPy, but also open a new avenue for preparing excellent seawater corrosion resistant microwave absorption materials.

Direct synthesis of bimetallic Co/Zn-MOF-derivative@mica composite for high microwave absorption performance and pearlescent properties

Direct synthesis of bimetallic Co/Zn-MOF-derivative@mica composite for high microwave absorption performance and pearlescent properties

Study of magnetism and microwave absorption performance of Fe5Ni3Si2

Study of magnetism and microwave absorption performance of Fe5Ni3Si2

Difunctional (heterogeneous doping of BN)@Fe3O4@Ppy composite for excellent microwave absorption performance in mid-to-low frequency range and high-efficient thermal management

Difunctional (heterogeneous doping of BN)@Fe3O4@Ppy composite for excellent microwave absorption performance in mid-to-low frequency range and high-efficient thermal management

Rational Construction of Decorated CoFeCuNiCr HEA and Hierarchical Mesoporous Cu3P in Gradient Double-Layer Nanocomposite Configuration with Highly Efficient Microwave Absorption Performance

Rational Construction of Decorated CoFeCuNiCr HEA and Hierarchical Mesoporous Cu3P in Gradient Double-Layer Nanocomposite Configuration with Highly Efficient Microwave Absorption Performance

Developing Robust FeSiAl/PEEK Composites for Wide-Temperature-Range Electromagnetic Wave Absorption.

Presently, researchers are placing emphasis on microwave absorption coating design while neglecting the research on materials that integrate both microwave absorption performance and mechanical properties. Here, robust FeSiAl/PEEK composites were prepared by a series process, including post ball-milling annealing, sol-gel method, and hot pressing. A detailed analysis of the electromagnetic (EM) parameters reveals the significant effects of morphology, filling ratio, and microstructure of FeSiAl on EM losses under a wide-temperature range. With 20 vol % filler loading, flaky-FeSiAl@SiO2/PEEK composite exhibits excellent performance for wide-temperature-range microwave absorption in the X-band. At room temperature, the minimal reflection loss (RLmin) reaches -28.6 dB at 10.8 GHz and the effective absorption bandwidth (EAB) is up to 3.26 GHz at 1.8 mm. As the temperature rises to 573 K, the RLmin reaches -25.8 dB at 11.2 GHz, and the EAB decreases to 2.04 GHz at a thickness of only 1.3 mm. The good performance is maintained over a wide-temperature range due to the SiO2 shell, which serves as an intermediate layer between FeSiAl and PEEK, not only improving impedance matching but also mitigating adverse eddy current losses at elevated temperatures. In addition, the SiO2 shell enhances the mechanical properties of the flaky-FeSiAl@SiO2/PEEK composite, with tensile strength reaching 84.38 MPa at 298 K, and remaining at 16.33 MPa at 573 K. Therefore, the flaky-FeSiAl@SiO2/PEEK composite emerges as a promising candidate for materials that integrate both superior microwave absorption performance and robust mechanical properties under wide-temperature-range conditions.

Microwave Absorption Performance of Durian-Husk-Derived Carbon Nanomaterials

The present research focuses on the development of highly efficient and lightweight electromagnetic wave (EMW) absorbers to address the growing issue of electromagnetic pollution. We investigate the use of carbon derived from biomass, specifically durian husks, to create carbon-based microwave absorbers with enhanced performance. A two-step process involving carbonization followed by potassium hydroxide (KOH) activation was employed to synthesize porous carbon materials. The microwave absorption properties were then analyzed using a vector network analyzer across a frequency range from 2 to 18 GHz, with a focus on key parameters such as reflection loss and complex permittivity. The sample, which was 2.0 mm thick and had 15% carbon nanomaterials mixed in with paraffin wax, had an optimal reflection loss of -30.8 dB at 12.8 GHz with an effective absorption bandwidth of 9.0 GHz, highlighting its strong electromagnetic wave absorption performance. The porous structure and large specific surface area significantly contributed to the material’s ability to absorb electromagnetic radiation. These findings highlight the potential of durian husk-derived carbon material as a highly effective and lightweight EMW absorber for practical applications.

Incorporation of nanocarbon materials of various dimensions enhances the microwave absorption properties of Nd-doped barium ferrite

AbstractPhysicochemical features of nano-carbon (NC) particles significantly influence the microwave absorption performances of NC-containing materials. Here, we report the development of rare earth neodymium (Nd)-doped barium ferrite (BaM) composites with carbon nanotubes (CNTs) and other NC materials (onion-like carbon and graphene oxide) to enhance microwave absorption. Nd0.15-BaM composites containing 8% CNTs demonstrate a minimum reflection loss of − 123.12 dB at 7.97 GHz, with an effective absorption bandwidth of 5.46 GHz in the 2–18 GHz range. CNTs improve impedance matching and synergize with Nd0.15-BaM, boosting absorption properties. The absorption performance is further tuned by adjusting the type and content of NC materials. These results highlight the potential of these composites for applications in wave absorption.

Influence of Absorber Contents and Temperatures on the Dielectric Properties and Microwave Absorbing Performances of C@TiC/SiO2 Composites.

TiC provides a promising potential for high-temperature microwave absorbers due to its unique combination of thermal stability, high electrical conductivity, and robust structural integrity. C@TiC/SiO2 composites were successfully fabricated using a simple blending and cold-pressing method. The effects of C@TiC's absorbent content and temperature on the dielectric and microwave absorption properties of C@TiC/SiO2 composites were investigated. The addition of C@TiC from 10 wt.% to 30 wt.% not only endows the composites with a higher dielectric constant and dielectric loss, but also with a greater high-temperature stability in terms of dielectric and microwave absorption properties. The composite with 30 wt.%C@TiC demonstrates a strong microwave absorption capability with a minimum reflection loss (RLmin) of -55.87 dB, -48.49 dB, and -40.36 dB at room temperature, 50 °C, and 100 °C, respectively; the 50 wt.%C@TiC composite exhibits an enhanced high-temperature microwave absorption performance with an RLmin of -16.13 dB and -15.72 dB at 200 °C and 300 °C, respectively. This study demonstrates that the TiC-based absorbers present an innovative solution for high-temperature microwave absorption, providing stability, versatility, and adaptability in extreme operational environments.

Facile synthesis and microwave absorption capabilities of hierarchical porous BN@C composites

With the rapid advancement of electronic information technology, the issue of electromagnetic radiation has become increasingly severe. It is urgent to develop high efficiency microwave absorber with excellent microwave absorbing performance. The construction of complex and diversified hierarchical porous structure is regarded as a promising way to enhance electromagnetic wave absorption. In this study, leveraging the porous architecture of melamine foam, a BN@C composite material featuring a hierarchical pore structure comprising larger and smaller pores, both residing in the micrometer regime, was synthesized via a high-temperature-assisted sol-gel method, using polyvinyl alcohol as the carbon precursor and boron nitride (BN) as the filler. By optimizing the molar ratio of raw materials, BN@C composites exhibiting superior microwave absorption performance were successfully obtained. When the matching thickness was set at 2.5 mm and 1.5 mm, respectively, the minimum reflection loss (RLmin) reached −29.12 dB, and the maximum effective absorption bandwidth (EAB) was 5.44 GHz, demonstrating a broad application prospect in the realm of microwave absorption. This research not only provides novel insights into enhancing the microwave absorption capabilities of carbon-based materials but also lays a material foundation for the development of electromagnetic radiation protection and stealth technologies.

Synthesis, Characterization, and microwave Absorbing performance of Mg0.8Zn0.1Co0.1Fe2O4 /CTO nanocomposite in 8–18 GHz frequency range

Synthesis, Characterization, and microwave Absorbing performance of Mg0.8Zn0.1Co0.1Fe2O4 /CTO nanocomposite in 8–18 GHz frequency range

Evolution characteristics of microwave absorbing carbon material on surface of CoFe2O4@biochar during hydrogen production from methane decomposition process

This study proposes a strategy to convert carbon deposits, generated during the catalytic decomposition of methane for hydrogen production, into high-performance microwave-absorbing materials. This approach not only reduces carbon emissions but also achieves carbon fixation and reuse, promoting environmental sustainability. The research demonstrates that cobalt ferrite (CoFe2O4)-loaded biochar catalysts, at different proportions, exhibit highly efficient and selective hydrogen production capabilities in the process of methane decomposition and hydrogen production, with a peak methane conversion rate as high as 83.6 %, which is higher than that of pure biochar catalysts. The improvement was significant, with an increase of 2.2 times. This catalyst not only strengthens the stability of methane decomposition, but also effectively shortens the reaction induction period, showing excellent catalytic performance and stability. Following methane cracking, an ordered, highly crystalline graphitic carbon structure forms within the catalyst, significantly improving its microwave absorption capacity. At a thickness of 1.3 mm, the catalyst’s microwave absorption reaches a peak value of −41.39 dB, with an effective absorption bandwidth of 4.56 GHz. The catalyst’s outstanding microwave absorption performance arises from synergistic mechanisms, such as multi-layer reflection and interface polarization, which effectively convert electromagnetic energy into thermal energy, facilitating efficient electromagnetic wave dissipation. This research presents an efficient catalyst for the clean utilization of methane resources and explores new pathways to convert industrial by-products into high-value materials, particularly with potential applications in microwave-absorbing technologies.

Enhanced dual frequency microwave absorption performance of magnetic-dielectric multi-interface regulated MWCNTS/MnFe2O4/Fe3O4/Co quaternary nanocomposite

Enhanced dual frequency microwave absorption performance of magnetic-dielectric multi-interface regulated MWCNTS/MnFe2O4/Fe3O4/Co quaternary nanocomposite

Biomass-based MnO2 Composite for Efficient Microwave Absorption Performance: Strong Interfacial Polarization and Electron Transition Effects

In this study, we explored the effectiveness of enhancing microwave absorption capabilities of biomass-derived porous carbon by introducing MnO2 through thermochemical techniques. The results showed that the MnO2-C exhibited higher values in both the real and imaginary parts of the dielectric constant compared to the Control, indicating that the addition of MnO2 significantly enhanced the energy storage and dissipation capabilities. Although the magnetic loss properties of the composite were relatively weak, the increase in conductive and dielectric losses compensated for this aspect. Moreover, the loading of MnO2 optimized the dielectric losses and promoted the reconstruction of charge, enabling MnO2-C to demonstrate superior microwave absorption performance, particularly in the high-frequency range. This is attributed to the multiple polarization mechanisms present in MnO2-C, including interfacial and dipolar polarization, which play a crucial role in enhancing dielectric losses. Additionally, a multilevel porous structure significantly enhanced the scattering and reflection of microwaves, further improving the absorption effectiveness. Consequently, these characteristics contribute to the MnO2-C achieving a minimum reflection loss value of -46.2dB and an expanded effective absorption bandwidth. Overall, the MnO2-C composite, with its optimized electromagnetic properties and complex microstructure, provides valuable insights for the development of new, highly efficient microwave absorption materials.

Honeycomb LiFe5O8/PANI nanocomposites with enhanced microwave absorption performance

Honeycomb LiFe5O8/PANI nanocomposites with enhanced microwave absorption performance

Investigation of Electromagnetic Wave Absorption Properties of Ni-Co and MWCNT Nanocomposites.

In recent years, severe electromagnetic interference among electronic devices has been caused by the unprecedented growth of communication systems. Therefore, microwave absorbing materials are required to relieve these problems by absorbing the unwanted microwave. In the design of microwave absorbers, magnetic nanomaterials have to be used as fine particles dispersed in an insulating matrix. Besides the intrinsic properties of these materials, the structure and morphology are also crucial to the microwave absorption performance of the composite. In this study, Ni-Co- MWCNT composites were synthesized, and the changes in electric permittivity, magnetic permeability, and reflectance loss of the samples were evaluated at frequencies of 2 to 18 GHz. Nickel-Cobalt-Multi Wall Carbon Nanotubes (MWCNT) composites were successfully synthesized by the co-precipitation chemical method. The structural, morphological, and magnetic properties of the samples were characterized and investigated by X-ray diffractometer (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Vibrating Sample Magnetometer (VSM), and Vector Network Analyzer (VNA). The results revealed that the Ni-Co-MWCNT composite has the highest electromagnetic wave absorption rate with a reflectance loss of -70.22 dB at a frequency of 10.12 GHz with a thickness of 1.8 mm. The adequate absorption bandwidth (RL <-10 dB) was 6.9 GHz at the high-frequency region, exhibiting excellent microwave absorbing properties as a good microwave absorber patent. Based on this study, it can be argued that the Ni-Co-MWCNT composite can be a good candidate for making light absorbers of radar waves at frequencies 2- 18 GHz.