Minimum Reflection Loss Value Research Articles

Hierarchical composite CoFe-K/GC@MnO2@MXene for excellent electromagnetic wave absorption

Electromagnetic wave absorption (EMWA) materials with qualities such as low cost, thin thickness, and high efficiency are of tremendous value in addressing the challenges posed by EMW pollution. Herein, we have successfully synthesized a nanoflower-like composite from the Prussian blue analog KCoFe(CN)6 through a combination of hydrothermal and post-annealing methods. Subsequently, we prepared the hierarchical composite CoFe-K/GC@MnO2@MXene (CMM) by electrostatic self-assembly with few-layered Ti3C2Tx nanosheets. Their chemical compositions, microstructures, and EMWA performances were thoroughly investigated. The CMM composite demonstrated outstanding EMWA performance with an impressive minimum reflection loss (RLmin) value of −53.0 dB at 1.68 mm and an effective absorption bandwidth (EAB) value of 4.0 GHz with an ultrathin-matching thickness of only 1.55 mm. The exceptional EMWA performance of CMM can be attributed to the increased conductive loss, enhanced interfacial polarization, and optimized impedance matching. Simulated radar cross-section (RCS) plots confirm the outstanding RSC reduction achieved by the CMM absorber coating. Furthermore, the EAB can be extended to 12.12 GHz by designing a macro 3D quadrangular frustum pyramid structural model for the absorber. The practical application potential of CMM was also enhanced by its good heat dissipation capability, which was demonstrated in real-time using an infrared thermal imager. This work provides a novel insight into developing efficient and multifunctional EMWA materials for practical applications.

Production of Lignin-Derived Functional Material for Efficient Electromagnetic Wave Absorption with an Ultralow Filler Ratio.

Industrial lignin, a by-product of pulping for papermaking fibers or of second-generation ethanol production, is primarily served as a low-grade combustible energy source. The fabrication of high-value-added functional materials with industrial lignin is still a challenge. Herein, a three-dimensional hierarchical lignin-derived porous carbon (HLPC) was prepared with lignosulfonate as the carbon source and MgCO3 as the template. The uniform mixing of precursor and template agent resulted in the construction of a three-dimensional hierarchical porous structure. HLPC presented excellent electromagnetic wave (EMW) absorption performance. With a low filler content of 7 wt%, HLPC showed a minimum reflection loss (RL) value of -41.8 dB (1.7 mm, 13.8 GHz), and a maximum effective absorption bandwidth (EAB) of 4.53 GHz (1.6 mm). In addition, the enhancement mechanism of HLPC for EMW absorption was also explored through comparing the morphology and electromagnetic parameters of lignin-derived carbon (LC) and lignin-derived porous carbon (LPC). The three-dimensional hierarchical porous structure endowed the carbon with a high pore volume, resulting in an abundant gas-solid interface between air and carbon for interfacial polarization. This structure also provided conductive networks for conduction loss. This work offers a strategy to synthesize biomass-based carbon for high-performance EMW absorption.

Microwave absorption properties of oriented Sm2Fe14BHx/polyurethane with planar anisotropy

Realization of microwave-absorbing materials with “small thickness, light weight, broad bandwidth, and low reflectivity” is an invariable topic. In this paper, Sm2Fe14BHx/polyurethane (SFBH/PU) composites with planar anisotropy were prepared by reduction–diffusion (R/D) and water bath hydrogenation (WBH) process. A minimum reflection loss (RL) value reaches −59.7 dB at the perfect matching frequency of 13.79 GHz with a thickness of only 1.035 mm. Compared with unhydrogenated SFB, the bandwidth and reflectivity are significantly improved. It is mainly attributed to the fact that introduction of hydrogen atoms effectively modulates the electromagnetic parameters and increases the Snoek limit ((μi−1)fr), which leads to the improvement of the high-frequency microwave absorption performance. In addition, the bandwidth equation is derived and simplified from the perspective of the reflected wave at the interface, which is in good agreement with the measured results.

One-step sintering construction of electromagnetic synergistic Co7Fe3/Co@CBC nanocomposites for enhanced microwave absorption properties.

Based on the synergistic modulation of electromagnetic parameters and microstructure design, multidimensional porous magnetic carbon-based nanocomposites have become ideal materials with efficient absorption properties. What's more, a carbon-magnetic alloy composite is a commonly used and efficient microwave absorber. In this paper, Co7Fe3/Co@CBC (CFCC) nanocomposites with strong magnetism, a three-phase composition, and a three-dimensional porous structure were synthesized by reducing Fe2+ and Co2+ using chestnut-shell biomass carbon (CBC). Biomass carbon with a higher specific surface area provides numerous active sites for Co7Fe3 nanosheets and Co nanospheres to form three-dimensional ping-pong chrysanthemum-like nanocomposites, which generate rich heterogeneous interfaces and conductive network structures. By adjusting the amount of added biomass, the electromagnetic parameters can be effectively regulated to achieve efficient microwave absorption properties. When the amount of biomass added varies within the range of 1.0 to 2.5 g, all samples exhibit a favorable effective absorption bandwidth (EAB) of over 5.88 GHz. In particular, the CFCC-2.0 composite exhibits optimal microwave absorption properties, with a minimum reflection loss (RLmin) value of -59.25 dB and an EAB of 6.34 GHz at a thickness of 2.8 mm. The simulation and modeling analysis results of radar cross section (RCS) further confirm the exceptional attenuation capability of composite materials at multiple incident angles. The exceptional microwave absorption properties and stability of EAB for the Co7Fe3/Co@CBC nanocomposite make it a promising candidate in the field of absorbing materials. This work also provides some feasible ideas for designing stable broadband wave-absorbing materials.

N-doped carbon layer cladded carbon sphere for broadband and boosted microwave attenuation capacity.

Structural construction and heteroatom doping are deemed effective strategies for designing a high-performance microwave absorbing composite to eliminate electromagnetic hazards. Herein, a series of core-shell structural carbon@N-doped carbon (C@NC) nanospheres were successfully fabricated without employing additional modifying agents and sophisticated operation. After incorporating them into a polyvinylidene fluoride (PVDF) matrix, the C@NC/PVDF composites possess tunable wave attenuation capacity obtained by regulating the coating layer thickness and filler loading. Benefitting from the design strategy of the core-shell structure and N-doped C, the C@NC-2/PVDF composites displayed the broadest effective absorption bandwidth of 6.29 GHz (11.71-18 GHz) under a filler content of only 10 wt% at 2.01 mm. Additionally, the minimum reflection loss value of C@NC-3/PVDF composites achieves -62.87 dB within the same mass ratio at a thickness of 2.35 mm. The excellent wave dissipation ability is attributed to the combination of optimized impedance matching and synergistically enhanced multiple loss mechanisms including conduction loss, interfacial polarization as well as dipolar polarization. This work offers a ponderable paradigm for the deeper exploitation of high-efficiency carbon absorbers.

Nano-Fe3O4 decorated on carbon aerogel framework: Coupling microstructures synergistic effect for electromagnetic wave absorption

Generation of multi-components synergistic absorbers is of value for efficient electromagnetic wave (EMW) absorption. This study constructed two kinds of nano-Fe3O4 decorated carbon aerogels with disparate microstructures (either Fe3O4 nucleated on the surface of carbon skeleton or the pore inside the aerogel) and highlighted the significance of the coupling microstructure on the EMW absorption capacity of the magnetic-dielectric material. The results demonstrate that the readily Fe3O4 coated and distributed carbon aerogel favors to improve EMW absorbing performance. A minimum reflection loss (RLmin) value of −51.8 dB is achieved at 4.9 GHz. In addition, the effective absorption bandwidth (EAB) covered the Ku bands under the matching thickness of only 1.8 mm. The favorable impedance matching and abundant hetero-interfaces collectively contribute to the EMW attenuation. The work with respect to interfacial structural control is of great reference value for designing excellent EMW absorber candidates.

Structural engineering of rare earth metal-organic frameworks derivatives with high anisotropy for high-efficiency electromagnetic wave absorption

Structural engineering and component design are crucial for conceiving outstanding metal-organic frameworks (MOFs)-based electromagnetic wave (EMW) absorption materials. However, an efficient and direct clarification of the structural influences on the EMW absorption performance of MOF-based absorption materials remains highly challenging and still awaits exploration. To this end, we synthesized a new type of rare earth (RE) MOFs with hexagonal-bipyramidal, snowflake-like, and dendritic structures through facilely controlling the solvent ratios in a scalable coprecipitation approach. The MOF-derived CeO2/Co/C hybrids with the same component content inheriting the morphological structures showcased tunable dielectric property and EMW absorption performance. The dendritic MOF derivatives with the highest anisotropy achieved a superior EMW absorption performance, manifesting a minimum reflection loss value of −71.5 dB at 1.7 mm and an effective absorption bandwidth of 5.2 GHz at 1.6 mm thickness, comparable to those of the best EMW absorbers. This work not only confirmed the high potential of RE MOF derivatives for EMW absorption, but also directly and efficiently unveiled the mechanism of morphological structure on the dielectric property and EMW absorption performance for the MOF-based EMW absorption material.

Design of porous SiC/MnO2 bulk composite with improved absorption of low-frequency electromagnetic waves

Silicon carbide (SiC) is expected to be the new-generation electromagnetic wave (EMW) absorber. In this context, the SiC/C composites were first prepared through a hydrothermal method using glucose as the carbon source. Then SiC/MnO2 composites were fabricated by a second hydrothermal reaction using potassium permanganate (KMnO4) as raw material. With glucose content increased to 10 wt%, the composition exhibited outstanding EMW absorption performance with the minimum reflection loss value of − 55.7 dB at the frequency of 2.1 GHz, and effective absorption bandwidth can cover the entire S-band by adjusting sample thickness. Therefore, the SiC/MnO2 composites present a promising EMW-absorbing material for low-frequency applications.

Component modulation and integrated multidimensional heterostructures of bimetallic MOFs derived 0D Co3ZnC/Co encapsulated in 2D CNTs-grafted 3D N-doped porous carbon polyhedron for high-efficient microwave absorption

Component modulation and multidimensional structural design are effective strategies to regulate the electromagnetic parameters and impedance matching, resulting in high-efficient microwave absorption. Herein, multidimensional integrated Co3ZnC/Co@C heterostructures compounding of 0D Co and Co3ZnC NCs, 1D CNTs and 3D porous carbon polyhedrons were fabricated by pyrolysis of bimetallic MOFs. Co and Co3ZnC NCs are uniformly encapsulated in CNTs-grafted porous carbon polyhedrons, forming 0D-1D-3D integrated heterostructures. The Co3ZnC/Co@C composites show component-modulated electromagnetic parameters and microwave absorption properties, which can be simply regulated by adjusting the ratio of Co/Zn in the MOFs precursor. With a filling ratio of 30 wt%, the optimal Co3ZnC/Co@C heterostructures show a minimum reflection loss (RL) value of −66.78 dB at 7.43 GHz with a thickness of 4.5 mm, located at the C band. The maximum effective absorption bandwidth (RL≤−10 dB) is up to 4.8 GHz (12.9–17.7 GHz) at only 2.0 mm. The high-efficient microwave absorption performance is attributed to that the multidimensional integrated heterostructures can sufficiently maximize the synergistic effects of each component. The uniformly distributed 0D Co and Co3ZnC NCs can promote magnetic loss and interfacial polarization. 1D CNTs are beneficial to enhance the conductive loss. 3D porous carbon polyhedrons grafted with CNTs are favored to promote the scattering of microwaves and impedance matching. These findings suggest a new insight to achieve high-performance microwave absorption by modulating the component and integrating multidimensional structures.

Surface modification of carbon fibers for enhanced electromagnetic absorption

The exceptional chemical and physical properties of carbon fiber make it highly promising for utilization in the field of wave-absorbing materials. However, the low magnetic loss and high complex permittivity of conventional carbon fiber materials limit their use in wave-absorbing materials. Hence, this study presents the synthesis of a FeCoNi/N-doped carbon coating/SCF composite with a distinctive microstructure by an in-situ reduction process. The successful formation of this unique architecture was confirmed through various characterization techniques. The composite material displayed both magnetic and dielectric characteristics. It showed an effective bandwidth spanning 14.77 GHz with a reflection loss (RL) of − 10 dB or less. In addition, it attained the minimum RL value of − 50.5 dB at a distance of 3.5 mm. The composite material is hypothesized to show great potential in electromagnetic wave absorption.

Hierarchical Flower-like Sulfides with Increased Entropy for Electromagnetic Wave Absorption.

The concept of high entropy is considered promising to enhance electromagnetic wave absorption properties. However, preparing high-entropy sulfides with unique structures for high-performance electromagnetic absorption remains a challenge. In this study, hierarchical porous flower-like dual-phase sulfides were designed with increased entropy and fabricated using a versatile approach. The porous flower configuration enhanced the scattering of electromagnetic waves and the impedance-matching characteristics. Additionally, the effect of high entropy induced diverse defects that were favorable for electromagnetic wave dissipation in dual-phase sulfides. The design of the dual-phase structure generated strong interface polarization, and the composition and content of the phases exhibited clear changes with the increase in the number of metal elements. Interestingly, apparent lattice distortions, defects, and shear strains were directly observed near the dual-phase interface of millerite (102) and pyrite (220) planes, facilitating the occurrence of dipole polarization. Consequently, the developed dual-phase high-entropy sulfide exhibited outstanding microwave absorption properties. The minimum reflection loss value of (FeCoNiCuZn)S was -45.8 dB at a thickness of 1.5 mm, and the optimal effective absorption bandwidth was 3.8 GHz at a thickness of 1.4 mm thickness. Thus, the design of high-entropy sulfides brings meaningful guidance for tuning the wave absorption properties in sulfides.

CNTs-improved electromagnetic wave absorption performance of Sr-doped Fe3O4/CNTs nanocomposites and physical mechanism

Electromagnetic wave pollution is a serious environmental problem, and it is urgent to develop high-efficiency electromagnetic wave absorption (EMA) materials. In this paper, carbon nanotubes (CNTs) were combined with Sr-doped Fe3O4 nanoparticles to form Sr-doped Fe3O4/CNTs nanocomposites with by hydrothermal method. After the characterization of microstructure and magnetic properties, EMA properties of Sr-doped Fe3O4/CNTs nanocomposites are investigated in detail. The well-dispersed CNTs lead to the uneven average grain size of Sr-doped Fe3O4 nanoparticles and a little decrease of saturation magnetization. While CNTs greatly improve EMA performance, and SFC1 sample exhibits the minimum reflection loss value of −65.64 dB at 6.32 GHz with the thickness of 3 mm. CNTs reduces the natural resonance of magnetic loss while increasing the permittivity, conductivity, and heterogeneous interfaces. As the result, Sr-doped Fe3O4/CNTs nanocomposites exhibit not only better impedance matching but also higher electric dipole polarization relaxation loss, interfacial relaxation loss, conductivity loss, and eddy current loss. In this way, the excellent EMA performance is attributed to the good impedance matching, intense dielectric loss and enhanced eddy current loss for Sr-doped Fe3O4/CNTs nanocomposites.

Mechanical and Electromagnetic Wave Absorption Performance of Carbonyl Iron Powder-Modified Nonwoven Materials

In order to develop carbonyl iron-enhanced electromagnetic wave-absorbing composites, this paper utilizes two different morphologies of carbonyl iron powder (CIP), spherical and flake-like, which are blended with aqueous polyurethane (PU) in three different ratios to prepare impregnating solutions. Polyester (PET) needle-punched nonwoven materials are impregnated with these solutions to produce electromagnetic wave-absorbing composites. First, electromagnetic parameters of the two CIP particle types, spherical carbonyl iron (SCIP) and flake-like carbonyl iron (FCIP), are tested with the coaxial method, followed by calculation of the results of their electromagnetic wave absorption performance. Next, the composites are subjected to microscopic morphology observation, tensile testing, and arched frame method electromagnetic wave absorption performance testing. The results indicate that the microwave absorption performance of FCIP is significantly better than that of SCIP. The minimum reflection loss value for F3, a kind of FCIP-modified nonwoven fabric, at the thickness of 1 mm, at 18 GHz is −17 dB. This value is even better than the calculated RL value of CIP at the thickness of 1 mm. The anisotropic shape of flake-like magnetic materials is further strengthened when adhering to the surface of PET fiber material. Additionally, the modified composites with carbonyl iron exhibit higher tensile strength compared with pure PET. The addition of fibrous skeletal materials is expected to enhance the impedance matching of flake-like magnetic particles, forming a wearable and microwave-absorbing composite.

MXene/bimetallic CoNi-MOF derived magnetic-dielectric balanced composites with multiple heterogeneous interfaces for excellent microwave absorption

The development of high-performance microwave-absorbing materials (MAMs) to address electromagnetic (EM) pollution has become a focus of attention for researchers. The combination of MXene and heterogeneous MOF with complementary advantages can be designed into novel composites with promising microwave absorption (MWA) properties. In this paper, the M/CoNi/C series composites derived from MXene/CoNi-MOF were prepared by in situ hydrothermal-pyrolysis process. The effects of the molar ratio of Co2+/Ni2+ and the addition amount of MXene on the morphology and EM parameters of the composites were investigated, and then the MWA performance and mechanisms of M/CoNi/C composites were analyzed. The results showed that the uniformly distributed CoNi and graphitic carbon in the M/CoNi/C composites formed a core–shell structure, and TiO2 nanoparticles modified on the carbon lamellas originated from MXene. The minimum reflection loss (RLmin) value of the optimized M/Co1Ni1/C reaches −61.34 dB only at the thickness of 1.9 mm, and the effective absorption bandwidth (EAB) value is 5.2 GHz only at 1.7 mm. The RLmin values in the thickness range of 1.5–3.0 mm are all less than −30 dB. The tunable microstructures, multiple interfacial polarizations, and dielectric-magnetic synergies optimize the impedance matching, which is conducive to achieving good broadband EM wave absorption performance. This paper provides a reference strategy for the design and construction of a high-performance MXene-based microwave absorber with controllable morphology and electromagnetic parameters.

Interface Engineering of Heterogeneous NiSe2‐CoSe2@C@MoSe2 for High‐Efficient Electromagnetic Wave Absorption

AbstractOptimization of components and micromorphology regulation are shown to be effective in boosting electromagnetic wave absorption (EMWA). One approach to achieve this enhancement is by utilizing the polarization effects of heterogeneous interfaces. Herein, NiSe2‐CoSe2@C@MoSe2 composites derived from NiCo‐MOF‐74 are fabricated via a facile selenization reaction and subsequent hydrothermal method. By varying the mass ratios of NiSe2‐CoSe2@C and MoSe2, a series of NiSe2‐CoSe2@C@MoSe2 composites with hierarchical flower‐like core–shell structures are obtained. The EMWA properties of the composites display a trend of initially increasing and then decreasing with the increasing content of MoSe2. Interestingly, when the mass ratio of NiSe2‐CoSe2@C and MoSe2 is 3:2, the minimum reflection loss (RL) value is −50.10 dB and an effective absorption bandwidth (RL< −10 dB) value can reach 4.80 GHz (13.20–18.00 GHz). The remarkable EMWA capability can be ascribed to the synergy effects of conductive loss, polarization loss, and suitable impedance matching. This work establishes a new pathway for the synthesis of transition metal dichalcogenides‐based composites, which hold great promise as high‐performance materials for EMWA applications.

Confined In-Situ Encapsulation of Co/C Composites with Increased Heterogeneous Interface Polarization for Enhanced Electromagnetic Performance.

It is an urgent problem to realize reliable microwave absorption materials (MAMs) with low density. To address this issue, a series of controlled experiments w ere carried out, which indicated that the tubular structure enables excellent microwave absorption properties with a lower powder filling rate. This performance is attributable to the combined dielectric and magnetic loss mechanisms provided by Co/C and the interface polarization facilitated by multiple heterogeneous interfaces. Particularly, Co@C nanotubes, benefiting from the enhanced heterointerface polarization due to their abundant specific surface area and the reduced electron migration barrier induced by their 1D stacked structure, effectively achieved a dual enhancement of dielectric loss and polarization loss at lower powder filling ratios. Furthermore, the magnetic coupling effect of magnetic nanoparticle arrays in tubular structures is demonstrated by micromagnetic simulation, which have been few reported elsewhere. These propertied enable Co@C nanotubes to achieve minimum reflection lossand maximum effective absorption broadband values of 61.0dB and 5.5GHz, respectively, with a powder filling ratio of 20wt% and a thickness of 1.94mm. This study reveals the significance of designing 1D structures in reducing powder filling ratio and matching thickness, providing valuable insights for developing MAMs with different microstructures.

High-performance electromagnetic wave absorption of NiS/Ni0.96S@multi-walled carbon nanotube composites

In this work, composites of heterogeneous nickel sulfide with multi-walled carbon nanotubes (MWCNTs) were prepared by a simple hydrothermal method. The dielectric loss capacity of composite materials is enhanced with the introduction of CNTs. Meanwhile, with the increase of CNTs content, the particle size of nickel sulfide decreases and the specific surface area increases, which is beneficial to enhance the microwave absorption capacity of the sample. The composite with the best microwave absorption performance was obtained by changing the NiS/Ni0.96S@MWCNTs mass ratio. By adjusting the NiS/Ni0.96S@MWCNTs mass ratio to 6:1, the effective absorption bandwidth is 3.76 GHz, corresponding to a thickness of 1.3 mm. Besides, the minimum reflection loss (RL) value was as high as –35.5 dB at 10.0 GHz with the thickness of 2.0 mm. The above results show that the prepared NiS/Ni0.96S@MWCNTs composite has the advantages of thin thickness, light weight, strong absorption and simple preparation, and is a microwave absorbing material with promising applications.

In situ growing CNTs/TiO2 heterojunction on MXene sheets for enhanced microwave absorption via multiple electron transfer paths and polarization

The novel two-dimensional Ti3C2Tx material exhibits great potential for microwave absorption owing to its 2D layered graphene-like structure and unique physical properties. However, the limited release of absorbing properties due to the low dielectric loss of Ti3C2Tx and its single loss mechanism pose challenges in meeting the functional requirements for microwave absorbers. Herein, carbon nanotubes (CNTs) were grown on the Ti3C2Tx substrates in a tip growth mode under the catalytic influence of Ni using the in situ induced method. Consequently, Ti3C2Tx/CNTs/TiO2 (TCT) structures were successfully prepared through carbonization conditions. It is worth noting that the composite material TCT-800 exhibits excellent absorption performance. The minimum reflection loss (RLmin) value reaches −44.6 dB when the matching thickness is only 1.4 mm, and the corresponding effective absorption bandwidth (EAB, RL < −10 dB) spans from 11.9 GHz to 15.9 GHz, totaling a range of 4.2 GHz. The excellent electromagnetic wave absorption performance of TCT-800 composites is attributed to the polarization phenomenon of more heterogeneous interfaces constructed by Ti3C2Tx nanosheets, CNTs, and TiO2 nanoparticles. This work provides a strategy for synthesizing Ti3C2Tx-based composites with strong electromagnetic attenuation and wide absorption bandwidth performance.

Hierarchical carbon nanotubes-modified heterogeneous composites derived from melamine-mixed ZIF-67/MXene for broadband microwave absorption

In this paper, carbon nanotubes (CNTs) modified TiO2/C/Co@C composites (TiO2/C/Co@C(CNTs)) with good electromagnetic (EM) wave properties were synthesized originated from ZIF-67/MXene composites supplemented with external carbon source melamine by in situ synthesis and high temperature pyrolysis. The effect of the melamine content on the microstructure, EM parameters, and the microwave absorption (MWA) properties of the TiO2/C/Co@C(CNTs) composites was investigated. The results showed that the in-situ grown CNTs were organically connected to the pyrolyzed ZIF-67/MXene derivatives to form a hybrid network structure. The composites achieve the minimum reflection loss (RLmin) value of −47.52 dB at a thickness of 1.5 mm, the effective absorption bandwidth (EAB) of 5.06 GHz at 1.8 mm with the RLmin value of −41.35 dB, and the RLmin value of −52.43 dB at 6.18 GHz. The excellent EM wave attenuation ability of the TiO2/C/Co@C(CNTs) composites covers nearly the entire frequency band of 2–18 GHz with the RLmin value almost less than −30 dB in the thickness of 1.5–5.0 mm. The unique microstructure, dielectric-magnetic synergistic effect, and multiple interfacial polarization optimize the impedance matching. This word proposes a promising new strategy for constructing highly efficient MOF-derived and MXene-based microwave absorbers.

Cross-scale construction of SiC–Si3N4 porous ceramics with superior electromagnetic wave absorption performance

A unique ceramic structure, which comprises whiskers in its pores and is capable of high-performance microwave absorption, has been designed by comnlining a sacrificial template method with catalytic nitriding. The influence of α-Si3N4 whisker content on the composition, structure, electromagnetic properties, and absorption properties of ceramics is also studied. The α-Si3N4 whisker content is controlled by changing the catalyst amount (FeCl2·4H2O). After adding 5 wt% FeCl2·4H2O, the highest α-Si3N4 whisker content is 78.06 %. The minimum reflection loss value of SiC–Si3N4 porous ceramics with thickness of 2.7 mm is −74.09 dB, rendering it superior than that of previously reported SiC-based absorbing ceramics. The supreior absorption performance is attributed to the reasonable structural design. The unique “whiskers in its pores” structure optimizes impedance matching, enhances attenuation loss and interference cancellation at three scales. This work provides new insights and ideas for the design and development of high-performance ceramic-based absorbing materials.