Wave Absorption Properties Research Articles

Analysis of influence of deep processing of metallic mineral materials on electromagnetic wave absorption performance

In this paper, the effects of deep processing of metallic mineral materials on electromagnetic wave absorption properties were studied. Firstly, the background and significance of the research are introduced, and the importance of metallic mineral materials in the field of electromagnetic wave absorption is expounded. Then the basic principle of electromagnetic wave absorption and the characteristics and influencing factors of metal mineral materials are discussed. In the section of deep processing technology, different processing methods and their applications are listed. Through experimental design and method, the electromagnetic wave absorption properties of metal mineral materials after deep processing are tested and analyzed. The experimental results are obtained and discussed. Finally, the application prospect of metallic mineral materials in electromagnetic wave absorption field is prospected, and the technical improvement and future development direction are put forward. This study provides an important reference for deepening the understanding of electromagnetic wave absorption properties of metallic mineral materials, and provides a reference for further research in related fields.

Volume exclusion effect and ambient temperature induced ultrahigh electromagnetic wave absorption properties of polylactic acid (PLA)/graphene nano‐platelets (GNPs) composites

AbstractConductive polymer composites (CPCs) have an excellent performance in dealing with electromagnetic (EM) radiation. The distribution of conductive fillers in CPCs plays a vital role in the electrical conductivity and EM wave‐absorbing properties. Moreover, the distribution evolution of GNPs in the PLA matrix caused by the enhanced volume exclusion effect via annealing was investigated. Polylactic acid with 8 wt.% graphene nano‐platelets (PG8) achieved best performance among the composites. After 5‐min heat treatment, the electrical conductivity and EM wave absorption properties of PLA/GNPs composites are significantly improved. With a simple treatment, the composite can reach an ultrahigh reflection loss (RL) value of −28.5 dB with a thickness of only 2.5 mm. By controlling the thickness in the range of 1–4 mm, the effective absorption bandwidth can be adjusted within 5.1–8.0 GHz. These methods provided in this work can effectively improve the EM wave absorption performance of CPCs and are worthy of being promoted.

Design and performance study of ultra-high temperature CaMnO3/polysilylaryl-enyne absorbing material

This work describes the preparation and properties of a novel category of thermosetting microwave absorbing composite materials. The composites were prepared by a simple solution casting process, employing high temperature resistant polysilylaryl-enyne (abbreviated as PSAE) resin as matrix and perovskite CaMnO3 (abbreviated as CMO) ceramic filler as absorbent filler. The microstructure, electromagnetic, wave absorbing and thermal properties of the CMO-PSAE composites were all examined. The results showed that the increasing fraction of CaMnO3 filler not only densified the microstructure of the composites, but also greatly improved their temperature resistance, thermal conductivity and wave absorption properties. The CMO-PSAE composite doped with 50 vol% CaMnO3 ceramic filler showed the strongest ability to absorb electromagnetic waves, with an effective absorption bandwidth (EAB) of 4.16 GHz and a minimum reflection loss is −53.01 dB. Besides, the thermal conductivity of the composite reached 1.106 W/(m·K). Furthermore, this composite material has exceptional thermal resistance, with the highest Td5 reaching 650 °C. Composites with varying doping levels can be used for specific performance needs in practical scenarios. Thus, such novel CMO-PSAE composites exhibit potential applications in the electromagnetic countermeasure field under high-temperature environments.

Synergy of micron graphite and fly ash for alkali-activated cementitious material: Electromagnetic absorption characteristics and mechanism

To attain a balance between compressive strength and electromagnetic wave absorption performance, this paper combined two electromagnetic wave loss mechanisms (magnetic loss and electrical loss), and prepared an environmentally friendly alkali-activated slag/fly cementitious material (ASFC) using micron graphite (MG) as the absorber and ground granulated blast furnace slag (GGBS) and fly ash (FA) as the precursors. The conductivity, electromagnetic wave absorption characteristics and compressive strength of ASFC with different ratios of GGBS and FA, MG size (800 mesh, 320 mesh, and 100 mesh), and content were investigated. The results indicated that when the ratio of GGBS and FA was 7:3, natural resonance and eddy current loss contributed to electromagnetic waves absorption at 8.2–11.0 GHz and 11.0–15.5 GHz range respectively. Additionally, the conductivity of MG/ASFC showed typical percolation characteristics, with the percolation threshold reached at a dosage of 3 wt%. In the 8.2–18.0 GHz, the incorporation of MG significantly augmented the conductive loss and polarization loss of ASFC. Furthermore, smaller-size MG was more beneficial for facilitating conductive loss of MG/ASFC among three different sizes. By adding 2 wt% of MG with 800 mesh, MG/ASFC can achieve a minimum reflection loss of −27.8 dB with a bandwidth of 3.0 GHz (Reflection loss ˂-7 dB). However, when compared to other cement-based absorbing materials reported, the MG/ASFC prepared in this experiment demonstrated better compressive strength and wave absorption properties. This finding contributing to a better understanding of green building materials with electromagnetic radiation protection capabilities.

Nano FeCoNi-based high-entropy alloy for microwave absorbing with high magnetic loss and corrosion resistance

With the development of modern communication and military technology, the protection of electromagnetic wave pollution and radar stealth technology have been widely concerned. In this background, the magnetic metals were widely used due to the strong ferromagnetism, which can induce strong magnetic loss to the electromagnetic wave. However, it remains challenging to precisely control the wave-absorbing performance of individual magnetic metals, and there are issues with poor corrosion resistance and high temperature resistance. Therefore, the alloy powders based on Fe, Co, and Ni in this work were prepared by wet chemical method at room temperature. Different from most of the traditional powder metallurgy methods, the wet chemical method enables us to obtain binary, ternary and quaternary alloys with a nanometer-scale and uniform distribution, all products have a microscopic morphology of 300–500 nm spheres. The FeCoNi alloy powder shows an effective absorption band (RL<-10 dB) of 7 GHz in the high frequency electromagnetic wave range at an ultrathin thickness of 1.5 mm, which has a high temperature magnetism (Tc >900 K) and excellent corrosion resistance. Further doping of Cu to form a quaternary alloy can improve the corrosion resistance and maintain the original wave-absorbing properties, while doping of Mo and Sn can adjust the position of the effective absorption bandwidth.

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.

Effect of nitrogen-doped reduced graphene oxide on the wave-absorbing properties of hollow ZnFe2O4

Effect of nitrogen-doped reduced graphene oxide on the wave-absorbing properties of hollow ZnFe2O4

Fabrication of hollow Ni/NiO/C/MnO2@polypyrrole core-shell structures for high-performance electromagnetic wave absorption

In response to the increasingly serious problem of electromagnetic wave pollution, there is a growing demand for materials capable of absorbing electromagnetic waves. A crucial strategy involves optimizing the microstructure and composition of these materials. In this study, the Ni/NiO/C/MnO2@PPy (NCMP) composites are successfully fabricated through the combination of hydrothermal method, high-temperature calcination process, chemical method and in situ polymerization. Due to the strong synergistic effect of the dielectric and magnetic components, and good impedance match, the NCMP-40 exhibits excellent electromagnetic wave absorption properties, with an optimal reflection loss (RLmin) of −56.23 dB at a thickness of 3.87 mm, and a high effective absorption bandwidth (EAB) of 6.86 GHz (10.68–17.54 GHz) at a thickness of 1.97 mm covering the entire Ku-band part of the X-band. Moreover, the radar cross section (RCS) attenuation is obtained through a simulation procedure. Compared to the sole perfect electrically conductive (PEC) layer, the PEC layer coated with NCMP-40 achieves an RCS value consistently below −10 dB m2 in the range of −60° < θ < 60°, and an RCS value is −22.0 dB m2 at θ = 0°. The prepared NCMP-40 presented herein shows excellent electromagnetic wave absorption performances. And this study provides a new method for the structural design of electromagnetic wave absorption materials.

Shellular SiCN ceramics with integrated structure and function realizing full electromagnetic wave absorption in the X-band

In this paper, the electromagnetic wave (EMW) absorption properties of SiCN ceramics with a shellular structure prepared by 3D printing technology (DLP) at different pyrolysis temperatures were investigated. The research shows that polarization loss and multiple reflections are the principal reasons for the improvement in sample absorption performance. The shellular structure is favorable for the multiple reflections and scattering of electromagnetic wave inside the material. The turbostratic carbon, graphitic carbon and SiC generated by pyrolysis are conducive to improving the dielectric loss of the sample, adjusting its impedance matching performance and improving its absorption performance. The RLmin of SiCN-1200 reaches − 21.12 dB (3.22 mm), and the effective band width is 4.20 GHz, covering the whole X-band. The excellent EMW absorption performance of DLP-SiCN ceramics, together with additive manufacturing, enable the integration of material, structure and function within a single component.

Electromagnetic wave absorption properties of Mn0.4Zn0.6Fe2O4 powders synthesized by high-temperature mechanochemical method

Herein, spinel Mn0.4Zn0.6Fe2O4 powders were fabricated utilizing a novel high-temperature mechanochemical method (HTMC), which achieves the coupling effect of high-temperature and mechanical force in a single process. The microstructure, chemical composition, magnetic properties, and electromagnetic wave absorption (EMWA) characteristics of the Mn0.4Zn0.6Fe2O4 powders were thoroughly considered in 2–18 GHz. The results reveal that with a matching thickness of 4.3 mm and a frequency of 6.2 GHz, S3 exhibits an effective absorption bandwidth that covers 4.56–7.48 GHz and has a minimum reflection loss (RLmin) of −43.8 dB. The excellent EMWA properties of the Mn0.4Zn0.6Fe2O4 powders can be ascribed to their effective cooperation between dielectric loss and magnetic loss as well as favorable impedance matching. Considering the performance enhancement generated by the distinctive coupling of multiple mechanisms in HTMC and the excellent EMWA properties of the as-prepared single Mn0.4Zn0.6Fe2O4 powders, it has significant potential in the field of fabricating efficient MAMs.

Improving electromagnetic wave absorption property of metal borides/carbon nanocomposites by magnetic-electric balance and ion substitution tuning strategy

Metal borides (e.g., MCoB) are widely used in the field of electrocatalysis due to their excellent electrochemical performance, but the poor dielectric loss limits their application in electromagnetic wave absorption (EMA). Thus, to improve the dielectric loss ability of metal borides, it needs to be compounded with dielectric materials. In this work, through reduction process and lyophilization process, Boride/PVP (MCoB/PVP) composites are obtained. After pyrolyzing these samples, Boride/Carbon (MCoB/C) nanocomposites are successfully synthesized. The EMA performance of nanocomposites are fine-tuned by balancing the magnetic and electric components and substituting metal elements of MCoB/C-X (M = Fe, Ni, Cu, X = 1, 2, 3). Among them, NiCoB/C-2 has the minimum reflection loss of −45.34 dB at thickness of 3.1 mm, and CuCoB/C-2 achieves an effective absorption bandwidth up to 6.92 GHz at thickness of 2.0 mm. This work proves the applicability of magnetic-electric balance and ion substitution tuning strategy. It also presents a new way for the application of metal borides in the field of EMA.

Fabrication of polydopamine-coated ZIF-67 derived Co@CN/rGO composite with excellent electromagnetic wave absorption properties

Constructing a reasonable microstructure and component modulation is considered as an effective way to improve the absorption performance of the absorbents. Herein, a series of Co@CN/rGOs composites were obtained via simple pyrolysis of dopamine-coated ZIF-67 loaded graphene oxide (ZIF-67@PDA/GO) at a high temperature. The existence of rGO after thermal treatment effectively improved dielectric loss. The multiple heterogeneous interfaces between rGO and the carbon layers formed by the polydopamine pyrolysis facilitated the interfacial polarization and relaxation. As a result, with only 20 wt% filler content, the RLmin value of Co@CN/10%rGO reached −49.98 dB at 5.50 GHz (low frequency) with a thickness of 4.5 mm. The effective absorption bandwidth increased to 5.70 GHz (10.26–15.96 GHz) by adjusting the thickness to 2.3 mm. This work provides a facile method for the construction of multicomponent nonhomogeneous interfaces and offers a novel strategy for the design of efficient absorbents.

Low-temperature synthesis of a novel diboride ceramic with electromagnetic wave absorption properties

Low-temperature synthesis of a novel diboride ceramic with electromagnetic wave absorption properties

Research Progress of MXene Composites In Electromagetic Wave Absorption

The issue of electromagnetic wave pollution is increasingly severe due to the rapid advancement of communication technology. Advanced electromagnetic wave absorbing materials have become an important research field. The excellent microwave absorption capabilities of the MXene composite can be attributed to its unique two-dimensional structure, abundant adjustable surfaces with functional groups, significant specific surface area, and high electrical conductivity. In this paper, the electromagnetic properties, electromagnetic wave absorption advantages and electromagnetic wave absorption principles of MXene compared with other materials are reviewed, and the wave absorption properties of MXene/graphene, MXene/carbon nanotubes, MXene/polymer, MXene/metal particles and MXene/oxide composites are summarized and analyzed. It is being investigated what the future holds for MXene and its mixed absorbent materials.

Design and preparation of an epoxy resin matrix composite structure with broadband wave-absorbing properties

Aiming at the poor effect of broadband wave-absorbing, the structural wave-absorbing composites structure were designed and prepared by choosing FeNi alloy powder/epoxy nanocomposites as the wave-absorbing interlayer, and carbon fibers/epoxy composites as the structural materials. Firstly, “80 wt% Fe50Ni50 alloy powder/epoxy resin nanocomposites” were successfully prepared, with a density of about 2.4 g/cm3, which can be applied as wave-absorbing interlayer. Then, electromagnetic parameters and loss mechanisms of the wave-absorbing sandwich in the frequency band of 1–18 GHz were studied in detail. Finally, the radar wave absorption characteristics of the structural wave-absorbing composites were optimized. The study shows that the electromagnetic loss mechanism of wave-absorbing sandwich is dominated by conductive loss and eddy current loss in the frequency range of 1–6 GHz, and eddy current loss, resonant loss and relaxation polarization in the frequency range of 6–18 GHz. In the frequency band of 2.5–8 GHz, the angular tangent of the magnetic loss of the interlayer is tanδm ≥ 0.5, and, the attenuation constant is stabilized in the range of 160–180 in the frequency band of 5.2–13.2 GHz, which shows that the interlayer has a good capacity of electromagnetic wave absorption. Different wave-absorbing properties can be designed by changing the thickness of the wave-absorbing interlayer. And the “fiberglass/interlayer/carbon fiber” composite board with a thickness of 2.0 mm interlayer and 3.0 mm-thick “fiberglass/ epoxy” has excellent broadband wave-absorbing properties. The sandwich composites have wave-absorbing peaks of |RL|≥10 dB in the frequency bands of 4.93–8.79 GHz and 14.96–18.0 GHz, with the peak width of 6.90 GHz, and the absorption peak of |RL|≥54 dB.

Preparation and microwave absorption properties of flexible composites containing Ag decorated polystyrene powders

Polystyrene (PS) microspheres have the advantages of good stability, corrosion resistance and low density, which have a broad application prospect. In this paper, PS composite microspheres with 20% silver plating content were prepared by chemical plating method and incorporated into polydimethylsiloxane (PDMS) flexible matrix to prepare Ag@PS/PDMS flexible wave-absorbing materials. The electromagnetic parameters were adjusted to optimize the dielectric and wave-absorbing properties by varying the additional amount of Ag@PS composite microspheres in Ag@PS/PDMS composites. The X-ray diffraction (XRD) results proved the successful preparation of Ag@PS composite microspheres. The SEM and EDS images indicated that the Ag particles were attached to the external surface of PS. The presence of Ag particles in the Ag@PS composite microspheres enhances their electrical conductivity and enables the formation of a conductive network. This, in turn, improves the composites’ dielectric constant. The optimal wave-absorbing capability of the composites was achieved when the Ag@PS composite microspheres were added at a weight percentage of 50%. When the sample attains a thickness of 1.8[Formula: see text]mm, a reflection loss of at least −39.8[Formula: see text]dB is attained at 10.4[Formula: see text]GHz, along with a bandwidth of 1.6[Formula: see text]GHz (9.1–10.7[Formula: see text]GHz) for the effective absorption bandwidth (EAB). The pressure-sensitive properties of the pliable composites were investigated as well. The optimal pressure-sensitive performance of Ag@PS/PDMS composites was achieved with a 60[Formula: see text]wt.% addition of Ag@PS composite microspheres. The resistance undergoes significant changes when subjected to pressure with a sensitivity of 9.7. The results indicate that the flexible composites’ wave-absorption and pressure-sensitivity properties can be modulated by adjusting the amount of Ag@PS composite microspheres added.

Novel ceramic matrix metastructure for high-temperature radar-infrared compatible stealth: Structure-function design and manufacture

Radar and infrared compatibility stealth at high temperature is difficult to achieve due to their opposing mechanism. Meanwhile, stealth structures are required to experience thermal insulation and load-bearing performance due to the high-temperature harsh environment and high velocity thermal airflows impacts. Currently, few materials can satisfy the above demands simultaneously. Herein, a ceramic matrix lattice sandwich metastructure with high-temperature radar infrared compatibility stealth characteristics, thermal insulation, and load-bearing capacities was exploited through the crossover design of electromagnetics, mechanics, and thermodynamics. A square lattice sandwich structure was constructed through interlocking technology with the rivaling out-of-plane compressive strength. The electromagnetic wave absorption property of metastructure is designed and optimized according to the equivalent circuit model based on the electrical loss theory. The metastructure exhibits excellent −10 dB absorption bandwidth at 800 °C of 4.5–14.8 GHz. Furthermore, the metastructure achieves infrared stealth at high temperature by reducing the surface temperature (from 1150 °C to 362 °C) of objects through gradient distribution structure. The lattice sandwich metastructure proposed here is expected to aid in the creation of advanced high-temperature multifunctional stealth materials.

The Design and Preparation of Permittivity-Adjustable FeNi@SrFe-MOF Composite Powders

When the thickness of the wave-absorbing material is low, there exists the problem of the narrow wave-absorbing frequency band, making it difficult to regulate the position of the wave-absorbing peak. In this study, FeNi@SrFe-MOF composite powders were synthesized using a hydrothermal method and a liquid-phase reduction method. The composite powder was spherical, with a particle size of about 50 μm–60 μm; the core layers of the powders were porous SrFe-MOF powders with permanent magnetization, and the outer layers were FeNi alloy nano-powder coatings with a particle size of 100 nm–120 nm, which took into account both the soft magnetization and the permanent magnetization properties of the composite powders. Additionally, a directional magnetic field was applied to the powder coating. By regulating the intensity and direction of the magnetic field, the electromagnetic parameters of the composite powder coating underwent sensitive changes, allowing for the precise regulation of the electromagnetic wave absorption performance of the composite powders. With the increase in magnetic field intensity, the ε′ value decreased significantly. The ε′ values were 8.56–7.35 for H453mT and 6.73–6.12 for H472mT. When no magnetic field was applied, the Snoke limit frequency of the μ′ value was 6.0 GHz. When the magnetic field intensity increased, the Snoke limit frequency of the μ′ value increased from 6.0 GHz, without the magnetic field, to 8.3 GHz; the Snoke limit of the composite powders was shattered. After the H453mT magnetic field regulation treatment, the powder coating exhibited good impedance matching characteristics with air. When the magnetic field intensity was 453mT and the thickness of the composite powders coating was 3.5 mm, the composite powders coating showed the strongest absorption peak when the R-value was −59 dB at 7.8 GHz, and the effective absorption bandwidth reached 3.2 GHz, exhibiting superb absorbent qualities. The wave absorption property of the coating can be sensitively changed by the magnetic field regulation treatment at the condition without changing the powder structure or coating structure, which provides a new strategy for the regulation of the wave absorption property and has broad application prospects.

THz‐Wave Absorption Properties of Organic–Inorganic Hybrid Perovskite Materials: A New Candidate for THz Sensors

Over the past two decades, organic–inorganic hybrid perovskite materials (OHP) have been extensively explored across various scientific disciplines, including physics, chemistry, and materials science, with a primary focus on solar cells. Building on numerous studies, the development of OHP‐based solar cells has transitioned into practical product realization, instilling the anticipation of novel solar cell advancements. Notably, OHP demonstrates versatility beyond its conventional application in solar cell materials. The physical properties of OHP materials exhibit a unique signature, thereby underscoring their potential utility as innovative functional materials, encompassing light‐emitting diodes, lasers, and photodetectors. Recent reports on terahertz (THz)‐wave absorption properties of OHP materials indicate a high possibility of their potential application as THz sensors. From the viewpoint of medical devices, which hold the most promising application potential, the exploration of optical phonon vibrational modes in the 0.5–3 THz frequency range is important. Moreover, understanding the correlations between atomic structure and lattice vibration modes is indispensable. In this concise review, the THz‐wave absorption properties exhibited by 3D OHP materials are meticulously explored. Furthermore, future research directions for THz sensors using OHP materials are suggested.

A Liquid‐Metal‐Assisted Competitive Galvanic Reaction Strategy Toward Indium/Oxide Core−Shell Nanoparticles with Enhanced Microwave Absorption

AbstractThe preparation of core–shell structured nanoparticles using the galvanic replacement reaction of liquid metals is a simple and efficient method. However, precise modulation of the core and shell components to regulate the microwave absorption performance still needs to be further explored. In this study, various types of indium/oxide core–shell nanoparticles are prepared based on a competitive galvanic reaction of gallium‐indium liquid metals. The prepared indium/oxide core–shell structured nanoparticles exhibit superior electromagnetic (EM) wave absorption properties with a minimum reflection loss (RL) of −40.25 dB at 1.7 mm and the widest effective absorption band of 6.12 GHz at 2.1 mm. The superior wave‐absorbing properties originate from the dielectric losses of the interfacial and dipole polarizations. In addition, an externally applied magnetic field improves the polarization loss and microwave dissipation to achieve a minimum RL of −45.65 dB at 2.4 mm. The liquid‐metal‐assisted competitive galvanic reaction strategies extend the variety of core–shell structured nanoparticles for electromagnetic wave absorption applications.