SiC-based composites for electromagnetic wave absorption

Summary

The development of cutting-edge technologies has put forward more stringent requirements for electromagnetic wave (EMW) absorbing materials, which need to maintain efficient EMW absorption in complex and harsh environments. Silicon carbide (SiC) composites, with their excellent thermal and chemical stability, can maintain efficient EMA absorption even in harsh environments, and have thus attracted widespread attention from researchers. This work first describes the main loss mechanisms of SiC materials, providing a solid theoretical basis for performance optimization. Secondly, the performance advantages brought about by the synergistic effect of SiC-based composite with other materials are highlighted. Finally, the differences between SiC and different materials after composite are summarized and the current problems of SiC-based composites are analyzed, providing ideas for the future design of SiC-based composites.

Graphical abstract

Physics; Electromagnetic waves; Applied sciences

Introduction

We are now in the 5G era. Wireless communication technology and electronic devices are now being used by many people,^1,2 electromagnetic waves (EMW) are increasingly integrated into people’s lives.^3,4 It is well-documented that extended exposure to intense electromagnetic (EM) radiation exerts a detrimental influence on public health.^5,6 In addition, such exposure has been shown to interfere with the normal operation of electronic devices.^7,8 EMW absorption materials can convert electromagnetic energy into thermal energy through dielectric loss and magnetic loss mechanisms, and can effectively avoid secondary radiation pollution.^9,10 In addition, The utilization of EMW absorbing materials within military contexts is of paramount importance, particularly in the context of evading radar detection for military equipment.^11,12 Consequently, the advancement of highly effective EMW absorbing materials is of significant strategic importance in order to safeguard public health, optimizing the quality of communication and maintaining national defense security.

In order to address the issue of EM pollution, a considerable number of studies have been dedicated to the development of high-performance EMW absorber materials that exhibit the characteristics of “light, thin, wide and strong”.^13,14 However, in light of the accelerated advancement in the domains of aerospace, military equipment and civil technology, EMW absorbing materials are facing more stringent requirements,¹⁵ and need to maintain high performance EMW absorption in complex and harsh environments.^16,17 Among them, dielectric loss materials are highly regarded for their noteworthy dielectric properties, considerable temperature resistance, and malleable designs.¹⁸ It is a well-established fact that dielectric loss materials are typically comprised of carbon-based materials, conductive polymers, ceramic materials, and transition metal compounds.¹⁹ Among these materials, silicon carbide (SiC) ceramic dielectric materials are regarded as the next-generation high-performance EMW absorbing candidates to meet the needs of extreme environment EM protection due to their high temperature resistance, tunable dielectric properties, diverse morphologies, light weight and high strength, and environmental stability.^3,20,21 However, the inherent poor match of impedance, single loss mechanism and narrow effective absorption bandwidth (EAB) of single-component SiC materials have severely limited the practical application of SiC materials in EMW absorption.^22,23

Previous studies have shown that composite modification and structural optimization of SiC materials can significantly enhance their EMW absorption efficacy.^24,25 SiC is combined with magnetic materials in order to form multicomponent materials, which possess a synergistic magnetic loss mechanism.²⁶ SiC in combination with carbon materials results in the formation of multicomponent composites, thereby facilitating the development of a synergistic dielectric loss mechanism.²⁷ Therefore, a systematic summary of SiC-based composites will strongly promote the development of such materials in the field of EMW absorption.²⁸ In this paper, the primary loss mechanisms of SiC materials are methodically delineated, thereby unveiling the intrinsic constraints of single-component SiC materials in the EMW energy dissipation process from a theoretical standpoint, providing theoretical support for performance optimization. Meanwhile, the effects of SiC composites with different magnetic metals and carbon materials on their EMW absorption properties are deeply analyzed. Finally, the differences between SiC and different materials after composite are summarized, and the current problems of SiC-based composites and the prospects for the future are analyzed, which is of great significance for the design and performance improvement of EMW absorption materials in the future.

The EMW loss mechanisms of SiC-based composites

The effectiveness of EMW absorption depends on two key factors: optimal resistance matching and strong EMW attenuation.^29,30 The latter converts EMW entering the material into heat or other forms of energy. However, superior EMW absorption is only possible if optimal impedance matching is achieved.³¹ According to the EMW transmission line theory, the impedance Z_in of EMW absorbing materials can be expressed by Equation 1.³² Reflection loss (RL) is a common method of evaluating the EMW absorption characteristics of a material, is expressed in Equation 2.^15,33

$$Z_{in}=Z_0\sqrt{{\mu }_r/{\epsilon }_r}\tanh \left[j\left(\frac{2\pi fd}{c}\right)\sqrt{\frac{{\mu }_r}{{\epsilon }_r}}\right]$$ (Equation 1)

$$RL=20\lg \left|\frac{Z_{in}-Z_0}{\left(Z_{in}+Z_0\right)}\right|$$ (Equation 2)

The air impedance is denoted by Z₀, the complex permittivity of the material is denoted by ε_r, the complex permeability of the material is denoted by μ_r, the imaginary unit is denoted by j, the frequency of the EMW is denoted by f, the thickness of the material is denoted by d and the speed of propagation of the EMW under vacuum conditions is denoted by c. When In the case of Z_in = Z₀, it can be deduced that the EMW will enter the material in its entirety.³⁴ When RL ≤ −10 dB, it has been determined that 90% of the EMW is absorbed, with the corresponding bandwidth being defined as the EAB.³⁵ It is evident that as the RL values decrease, there is an observable increase in the capacity for EMW absorption.^7,36

On the other hand, the attenuation ability of EMW absorbing materials is mainly determined by the dielectric loss as well as the magnetic permeability,^37,38 and these two types of loss mechanisms together determine the efficiency of EM energy dissipation. SiC is a dielectric ceramic material which exhibits a number of desirable properties, including excellent dielectric properties and good physicochemical stability.^39,40 However, SiC materials do not have magnetic losses by themselves, and in past studies magnetic metals were usually coupled with SiC to form multicomponent materials to enhance their magnetic and conductive losses.⁴¹ Therefore, this paper does not discuss the magnetic loss of the material.

Dielectric loss

As a typical dielectric loss material, an exhaustive inquiry into the dielectric loss mechanism of SiC can help to understand the attenuation behavior of EMW and determine new directions for the advancement of EMW absorbing materials.

Dielectric loss mainly includes forms such as polarization loss and conduction loss,^33,42 as illustrated in Figure 1. Many studies have used these mechanisms to explain the loss of EMW and have found evidence to prove their effectiveness. According to Debye’s theory, the real part of the dielectric constant (ε′) and the imaginary part of the dielectric constant (ε′′) can be expressed by the following formulas:⁴³

$${\epsilon }^{\prime }={\epsilon }_{\infty }+\frac{{\epsilon }_s-{\epsilon }_{\infty }}{1+{\left(2\pi f\right)}^2{\tau }^2}$$ (Equation 3)

$${\epsilon }^{″}=\frac{2\pi f\left({\epsilon }_s-{\epsilon }_{\infty }\right)}{1+{\left(2\pi f\right)}^2{\tau }^2}+\frac{\sigma }{2\pi f{\epsilon }_0}$$ (Equation 4)

Figure 1.

Schematic diagram of dielectric loss mechanism

According to Equations 3 and 4, the permittivity of free space is denoted by ε₀, the static dielectric constant is denoted by ε_s, he dielectric constant at infinite frequency is denoted by ε_∞, the relaxation time is denoted by τ, and the conductivity is denoted by σ.

Polarization loss

Polarization can be categorized into the following types: electronic, ionic, dipolar, and interfacial,⁴⁴ each corresponding to a different EMW frequency band.⁴⁵ Electronic polarization is attributable to the displacement of the electron cloud in relation to the atomic nucleus, while ion polarization is the consequence of a shift in the respective position of positively and negatively charged ions.²⁸ Both occur at higher frequency bands, not applicable to the commonly studied range of 2–18 GHz,⁴² and contribute negligibly to the depletion mechanism. The defect induced polarization mechanism is predicated on the premise that defect sites within the absorber have the capacity to capture charge carriers, thereby disrupting the original charge equilibrium distribution and inducing the polarization effect.^46,47 This process is accompanied by the dissipation of EMW.^48,49 Dipole polarization is a process in which polar molecules or dipoles within a material undergo orientational polarization by EMW and convert EM energy into thermal energy through a relaxation loss mechanism.^50,51 Interfacial polarization is usually manifested at heterogeneous interfaces, where charges are distributed unevenly and exert work through directional movement in response to an applied electric field, consuming the energy of the electric field.⁵²

Conductive loss

When EMW exists within a material, the free charge within the material is caused to move by the effect of the applied alternating EM field will produce induced currents, in the process of the electric field on the moving charge to do work, proportion of the electrical energy is transformed into heat, thereby generating the ability to dissipate, this process for the conductive loss.^53,54,55 The magnitude of conductive loss is directly proportional to the conductivity of the material; as conductivity increases, so too does conductive loss.^56,57 However, elevated conductivity has the potential to engender a skin effect on the material’s surface, resulting in substantial impedance mismatch.⁵⁸

SiC-based composite EMW absorbing materials

As a material with remarkable dielectric properties and mechanical properties,⁵⁹ SiC can be applied in many extreme environments and has been the subject of extensive research in the field of efficient absorption of EMW.^60,61 However, the fact that single-component SiC materials possess a single loss mechanism and low conductivity represents a considerable challenge in attaining the ideal state of “wide, strong, light, and thin” of EMW absorbing materials.⁶² Combining SiC with other materials is an effective way to solve the aforementioned problems.⁶³

SiC/magnetic metal composite material

Magnetic metals (Fe, Co, and Ni), as good conductive and magnetic materials, can dissipate EMW through conductive and magnetic losses,⁶⁴ showing great potential in the domain of EMW absorption.⁶⁵ Research conducted on EMW absorbing materials has demonstrated that the amalgamation of SiC with magnetic materials to form multi-composite materials is conducive to a magnetic-dielectric loss mechanism which exhibits a marked synergistic effect, thereby leading to an improvement in the performance of EMW absorption.^26,66

SiC/Ni composite material

The magnetic metal Ni is not only abundant but also has excellent corrosion resistance and mechanical strength.⁶⁷ As shown in Figure 2A, Wang et al.⁶⁸ prepared SiC@Ni composites with hollow core-shell structure by sacrificial template method and reduction reaction. These composites demonstrated an exceptional capacity for EMW absorption when subjected to a reduction temperature of 750°C, with a minimum reflection loss (RL_min) of −55.7 dB and a maximum EAB (EAB_max) of 8.8 GHz. As presented in Figure 2B, Wang et al.⁶⁹ fabricated Ni@SiC core-shell structured composites by electroless nickel plating method, which exhibited good EMW absorption performance. In addition, they also explored the effect of SiC particle size on the EMW absorption performance of the composites. The composites with 60 μm SiC particles had a RL_min of −50.27 dB at 8.04 GHz, while those with 5 μm particles achieved a RL_min of −66.10 dB at a thickness of 3.4 mm. The problem of high density of magnetic particles can limit the combination of SiC and magnetic components. However, preparing porous SiC materials can effectively solve the above problem.⁷⁰ Xu et al.⁷¹ fabricated SiC/SiO₂ composites with magnetic Ni nanochannels (NSPC), which had a unique foamy porous structure. This material achieved a strong RL_min of −64.86 dB and an ultra-wide EAB_max of 13.20 GHz at a thickness of 1.46 mm (Figure 2C).

Figure 2.

Preparative process and EM absorption performance of SiC/Ni composite material

(A) Schematic diagram of the synthesis process of H–SiC@Ni core-shell composites, as well as three-dimensional RL diagrams and RL curves of different thicknesses at 750°C. Reproduced with permission.⁶⁸ Copyright © 2024, Elsevier.

(B) The preparation procedure of Ni@SiC and 3D color mapping of RL. Reproduced with permission.⁶⁹ Copyright © 2025, Springer.

(C) The synthesis process for Ni/SiC/SiO₂ porous composites and the 3D images of reflection loss curves for S3. Reproduced with permission.⁷¹ Copyright © 2023, Elsevier.

SiC/Fe composite material

Ferromagnetic materials have high saturation magnetization and anisotropic fields, making them excellent EMW absorbers.⁷² Javid et al.⁷³ synthesized carbon-coated SiC/Fe nanowires ((SiC/Fe)@C NWs) in-situ by using a simple arc discharge plasma technique, which exhibited excellent EMW absorption performance at a filler content of 25 wt %, with an RL_min of −63.44 dB and an EAB_max of 7 GHz, as well as good impedance matching and corrosion resistance (Figure 3A). Due to their low cost and design flexibility, ferrites are widely used as EMW absorbing materials.^49,74 Liang et al.⁷⁵ successfully prepared SiC-Fe₃O₄ core-shell structured hybrid nanowires by a facile polyol method. The coverage density of Fe₃O₄ on SiC can be controlled by adjusting the mass ratio of the precursors, and an RL_min of −51 dB was achieved at an optimized ratio (SiC:Fe(acac)₃ = 1:4) (Figure 3B). Soft magnetic intermetallic compound Fe₃Si exhibits characteristics that are reminiscent of both silicides and metallocene compounds, including excellent corrosion and oxidation resistance, as well as excellent thermal stability. Xiang et al.⁷⁶ successfully prepared Fe₃Si/SiC composites by an in-situ carbothermal reduction strategy. The samples exhibit superior EMW absorption at low filler (10 wt %) with RL_min of −61.67 dB and EAB_max of 6.96 GHz, while meeting the comprehensive requirements of lightweight and strong absorption performance (Figure 3C).

Figure 3.

Preparative process, TEM images, and EM absorption performance of SiC/Fe composite material

(A) Pictorial representation of the formation mechanism of (SiC/Fe)@C NWs under VLS growth, and microwave absorption performance plots of (SiC/Fe)@C NWs. Reproduced with permission.⁷³ Copyright © 2021, Elsevier.

(B) TEM images of SiC-Fe₃O₄ hybrids and the calculated RL values of SiC nanowires. Reproduced with permission.⁷⁵ Copyright © 2014, Royal Society of Chemistry.

(C) The preparation process of Fe₃Si/SiC composites, and the 3D and 2D images of RL curves for S-4. Reproduced with permission.⁷⁶ Copyright © 2023, Elsevier.

SiC/Co composite material

Co not only has high saturation magnetization and high Curie point, but also has better oxidation resistance than ferromagnetic metals.⁷⁷ Guan et al.⁷⁸ describes a SiC/Co composite fiber prepared by liquid-phase method and hydrothermal annealing. The EM attenuation characteristics are tunable via adjustments to cobalt nanoparticle size and concentration, where reduced particle dimensions enhance magnetic dissipation. The best performance was achieved at a Co content of 47.9 wt %, with an RL_min value reaching −78.0 dB and the EAB_max of 6.6 GHz (Figure 4A). Combining Co nanoparticles with CNTs/SiC not only enhanced dielectric loss, interfacial polarization and magnetic loss but also solved the problem of magnetic particle aggregation. As illustrated in Figure 4B, Dong et al.⁷⁹ optimized the hierarchical structure of Co/CNT@SiC composites by controlling the pyrolysis temperature (600°C–1000°C) to obtain the best absorption performance at 900°C with an RL_min of −64.16 dB (at 11.2 GHz and 2.28 mm thickness) and an EAB_max of 8.02 GHz. Zhao et al.⁸⁰ proposed an efficient, easy-to-synthesize, and low-cost strategy: modifying SiC fibers by a simplified method to generate Co nanoparticles and multi-walled CNTs (SiC@Co/CNT) on the surface of SiC fiber. An RL_min of −70.22 dB and an EAB_max of 6.03 GHz (covering the Ku-band) were achieved by this composite (Figure 4C). Tian et al.⁸¹ proposed a flexible EMW absorption material based on carbon cloth (CC) loaded Co₃O₄ arrays. By regulating the load state of Co₃O₄ to achieve excellent EMW absorbing performance (RL_min = −54.43 dB, EAB_max = 4.54 GHz) (Figure 4D), a new approach to preparing high-performance and flexible ENW absorbing materials is provided.

Figure 4.

Preparative process and EM absorption performance of SiC/Fe composite material

(A) The fabrication schematic of SiC/Co composite fibers and EMA performances of specimens. Reproduced with permission.⁷⁸ Copyright © 2023, Elsevier.

(B) Schematic diagram of Co/CNT@SiC composite preparation, and 3D reflection loss maps and projection planes of T4. Reproduced with permission.⁷⁹ Copyright © 2025, Royal Society of Chemistry.

(C) Synthesis process of SiC@Co/CNT and RL curves. Reproduced with permission.⁸⁰ Copyright © 2024, Springer.

(D) The sketch map showing the synthetic route for flexible Co3O4/CC composites, and The detailed RL diagrams in different thicknesses. Reproduced with permission.⁸¹ Copyright © 2023, Elsevier.

SiC/carbon composite material

Carbon materials are extensively employed in the field of EMW absorption, a consequence of their advantageous electrical conductivity, elevated degree of stability, and diverse microstructures.^82,83 SiC composite with carbon materials can effectively improve the impedance matching and broaden the EAB.⁸⁴ Carbon materials have diverse structures, including but not limited to expanded graphite (EG),⁸⁵ carbon nanofibers (CNF),⁸⁶ carbon nanotubes (CNT),⁸⁷ and even amorphous carbon obtained from biomass.^88,89

SiC/EG composite materials

EG possesses a substantial pore structure, an extensive specific surface area, and elevated surface activity.⁹⁰ As shown in Figure 5A, Hao et al.⁹¹ synthesized composites of SiC nanowires (SiCNWs) on EG by chemical vapor phase reaction method with an RL_minof −52.76 dB and an EAB_max of 3.74 GHz. Xu et al.⁹² prepared a 2D accordion like structured SiC/C composite using EG via a carbothermal reduction method. This material demonstrated excellent EMW absorption performance at an ultra-low filling ratio (3 wt %) with an RL_min of −54.52 dB and an EAB_max of 4.80 GHz (Figure 5B), and verified their efficient EMW dissipation capability in real-world environments by radar scattering cross-section simulations.

Figure 5.

Preparative process and EM absorption performance of SiC/EG composite material

(A) Schematic illustration of the growth of SiC nanowires on expanded graphite and 3D representations of RL values. Reproduced with permission.⁹¹ Copyright © 2022, Elsevier.

(B) Schematic illustration of the preparation of 2D accordion-like SiC/C composites, and EMW absorption properties and the 3D and 2D images of RL curves. Reproduced with permission.⁹² Copyright © 2023, Elsevier.

SiC/CNF composite materials

CNF demonstrates considerable potential for EMW absorption, attributable to its favorable dielectric constant, minimal density, and substantial specific surface area.⁹³ Zhang et al.⁹⁴ prepared one-dimensional beaded SiO₂@SiC@C nanofibers (SSCF) composite materials with multiple heterogeneous interfaces via electrostatic spinning⁹⁵-carbothermal reduction. This material achieved an RL_min of −59.53 dB and an EAB_max of 6 GHz (Figure 6A). The outstanding EMW absorption capability can be ascribed to the cooperative interaction between heterogeneous phase constituents and the unidirectional conductive architecture, which collectively improved impedance matching characteristics while strengthening diverse energy dissipation pathways. The extremely high porosity and unique network structure of SiC/CNF aerogels make them highly sought after for use in EMW absorption applications. As presented in Figure 6B, Du et al.⁹⁶ fabricated biomass-derived CNF aerogel from bacterial cellulose, and then SiC nanowire-CNF membranes were obtained by in-situ growth of SiC nanowires in CNF. The prepared aerogel ensures excellent EMW absorption while also being ultra-light, fire-resistant, and low thermal conductivity, making it suitable for use in fields such as construction and aerospace. Dai et al.⁹⁷ introduced a lightweight CNF-reinforced SiC/C (CF-SC) aerogel, which exhibits an excellent three-dimensional porous structure and EMW absorption properties, and achieves an RL_min of −52.6 dB and an EAB_max of 8.6 GHz (Figure 6C), covering the entire Ku-band.

Figure 6.

Preparative process and EM absorption performance of SiC/CNF composite material

(A) Schematic diagram of the synthetic strategy for SSCF and 3D diagrams of calculated RL curves. Reproduced with permission.⁹⁴ Copyright © 2024, Elsevier.

(B) Schematic formation process of SiC-CNF aerogel films and RL of CNF and SiC-CNF aerogel films. Reproduced with permission.⁹⁶ Copyright © 2021, Springer.

(C) Schematic illustration of the CF-SC aerogel preparation process and RL curves. Reproduced with permission.⁹⁷ Copyright © 2023, Elsevier.

SiC/CNT composite materials

CNTs possess advantages such as high aspect ratio and excellent mechanical properties, so they have outstanding competitiveness in the field of carbon-based EMW absorbing materials.⁹⁸ As demonstrated in Figure 7A, Liu et al.⁹⁹ reported a SiC/C aerogel prepared by performing carbothermal reduction. This material achieved an ultra-wide EAB_max of 11.04 GHz, covering the entire X-and Ku-bands as well as part of the C-band. Xu et al.¹⁰⁰ used ferrocene as a carbon source and catalyst to grow CNTs on SiC fibers on a large scale, obtaining CNT/SiC fiber composites with an RL as low as −62.5 dB, an EAB_max up to 8.8 GHz (Figure 7B), and the performance can be modified by altering the CNT composition, width and filler incorporation.

Figure 7.

Preparative process and EM absorption performance of SiC/CNT composite material

(A) Schematic diagram of the synthetic strategy for SSCF and 3D diagrams of calculated RL curves. Reproduced with permission.⁹⁹ Copyright © 2025, Royal Society of Chemistry.

(B) Schematic diagram of the synthesis process of CNT/SiC_f composite and RL. Reproduced with permission.¹⁰⁰ Copyright © 2020, American Chemical Society.

Biomass as carbon source

As the most abundant renewable carbon source in nature, biomass has attracted much attention in the preparation of functionalized carbon materials and is ideal for the synthesis of SiC nanowires due to its unique microstructure, low cost, good sustainability, and environmental friendliness.^{101,102,103,104} Liu et al.¹⁰⁵ prepared C/SiC composites (HPCC) with multilevel porous structure by carbonization and gas-phase-solid-growth method using the natural porous structure of dried apples as a template. The composite achieved an RL_min of −44.2 dB (1.5 mm) and an EAB_max of 4.2 GHz (Figure 8A). Xie et al.¹⁰⁶ synthesized SiO₂/SiC_nw using waste coffee shell biochar. The material prepared at 1600°C exhibited an RL_min of −50.40 dB at 6.3 GHz a (3.3 mm), with an EAB_max of 4.52 GHz (Figure 8B). This work provides a new pathway for the high-value recycling of waste biomass and the development of efficient wave-absorbing materials. As seen in Figure 8C, Zhang et al.¹⁰⁷ tuned the microstructure of pomelo peel biomass porous carbon material by growing SiC nanowires in situ, which significantly enhanced the EMW absorption performance, with an RL_min of −60.72 dB (1.74 mm) and an EAB_max of 5.52 GHz.

Figure 8.

Preparative process and EM absorption performance of SiC/CNF composite material

(A) Schematic illustration for preparation process of the SiC_w@C aerogel and RL and EAB. Reproduced with permission.¹⁰⁵ Copyright © 2024, Elsevier.

(B) Schematic of SiO₂/SiC_nw growth mechanism, and RL and impedance matching (Z). Reproduced with permission.¹⁰⁶ Copyright © 2024, Elsevier.

(C) The preparation of biomass porous carbon material and RL curves. Reproduced with permission.¹⁰⁷ Copyright © 2024, Elsevier.

Conclusions and perspectives

In order to study the materials that can maintain efficient EMW absorption in harsh environments, many researchers have focused on SiC-based composites with high temperature resistance and excellent stability for in-depth investigation. Table 1 compares the differences between pure SiC materials and SiC composite materials in terms of RL_min and EAB_max values. It is evident that SiC can significantly improve its EMW absorption performance when combined with other materials.

Table 1.

Comparison of EMW absorption performance based on SiC materials

Category	Materials	RLmin (dB)	Thickness (mm)	EABmax (GHz)	Thickness (mm)	Reference
Pure SiC	3D braided SiCf/SiC	−16.1	5	1.5	5	Han et al.108
	SiC nanowires	−21.39	2.5	3.5	2.5	Kuang et al.109
	SiC powders	−35	1.5	1.34	1.5	Wang et al.110
SiC composite materials	FeSi/SiC	−57.10	3.0	4.34	1.2	Xue et al.111
	SiC/multilayer graphene	−53.62	2.04	0.82	2.04	Hao et al.112
	PVA/SiC/RGO	−61.02	2.5	7.04	2.5	Huo et al.113
	SiC/MWCNTs	−57.36	1.5	3.34	1.5	Xia et al.114
	SiCNWs@MnO2@PPy	−50.59	2.46	6.64	2.46	Zhang et al.115
	SiC/SiOx Micro/nanofiber Sponges	−51.8	2.26	8.6	3.0	Yan et al.116
	SiCf/Si3N4–SiC	−60.5	4.0	7.14	2.9	Xing et al.61
	Biomass-derived carbon-based SiC	−51.27	2.0	4.64	2.1	Wang et al.117
	SiC@Fe	−73.75	4.99	4.4	4.99	Xiang et al.118
	(CFO NPs) SiC/C NFs	−56.52	2.0	5.05	2.0	Wang et al.119
	FeSi/CoSi/SiC	−53.13	1.63	2.77	1.63	Zeng et al.120

Magnetic materials can cause significant magnetic losses in magnetic resonance and eddy currents. The composite of SiC with magnetic materials can enhance the complex magnetic permeability value, thereby improving the material’s impedance matching capability. Carbon materials possess excellent chemical stability and dielectric loss properties, are abundant and come in many forms, and when combined with SiC, they can provide more opportunities for microstructural design. The composite of SiC and carbon materials offers advantages in improving microwave absorption characteristics in the C, X, and Ku bands, significantly enhancing the EAB. Both SiC composites with magnetic materials and carbon materials can form heterogeneous interfaces to enhance interface polarization and create various structures to form conductive networks, thereby enhancing conductive loss. Additionally, the structural defects in composite materials lead to dipole polarization, which plays a crucial role in improving their EMW absorption performance. In summary, SiC-based composite materials can maintain their ability to withstand harsh environments while providing efficient EMW absorption performance.

Although SiC-based composites have made some progress in previous studies, we still face some challenges. Firstly, the final performance of EMW absorbing materials is affected by the synergistic effect of multiple mechanisms, and due to the lack of theoretical support for the quantitative analysis of the influencing factors, it is difficult to precisely regulate the ratios of the composite system of SiC and other components to achieve the optimal performance. Secondly, although some SiC-based composites have excellent performance, their preparation process is complicated, with long cycle time and high cost, which makes it difficult to realize industrialized production; or the preparation process involves polluting reagents, which is contrary to the actual demand for the development of environmentally friendly materials. Although biomass-derived SiC composites have environmentally friendly and low-cost features, but the existing technology can not regulate its structural morphology and size, cannot be stabilized to obtain a unified structure of SiC-based composites, difficult to achieve industrialization. Thirdly, most of the existing research focuses on the optimization of a single property. In the future, it is necessary to make full use of the advantages of SiC-based composites to design multifunctional high-efficiency EMW absorbers integrating high-temperature resistance, antifouling, flame retardancy and wearability.

To further improve the performance of SiC-based composite materials, in-depth research can be conducted in the following areas to achieve optimal structural design and performance optimization. First, by leveraging artificial intelligence, a database of EMW-absorbing materials can be established to more intuitively and precisely observe the correlation between material performance improvements and variables, enabling the design of more reasonable formulations. This approach also allows for a clearer understanding of the EMW absorption mechanism. Second, most SiC composites are synthesized using traditional methods such as chemical vapor deposition (CVD), precursor impregnation pyrolysis (PIP), and carbon thermal reduction. The first two methods have long cycles, while the third method lacks structural consistency. We can adopt combined processes or innovate and optimize processes tailored to different synthesis methods based on specific requirements. Third, given the increasing demands for EMW absorption materials, future efforts should fully leverage the advantages of SiC-based composite materials to design multifunctional, high-efficiency EMW absorbers that integrate high-temperature resistance, anti-soiling, flame retardancy, and wearability. Finally, the structure of SiC composites is closely related to their EMW absorption performance. Structures such as hollow structures, core-shell structures, and porous structures can enhance EMW absorption performance by improving impedance matching, increasing conduction losses, interface polarization, and multiple scattering. SiC-based composite materials with 3D structures often have high porosity, enabling multiple scattering and facilitating impedance matching. Complex structures also form conductive networks that enhance conductive loss. Additionally, abundant interfaces and defects can lead to increased polarization loss.

Acknowledgments

This research was funded by the (grant no. 52003111 and U20A20340) National Natural Science Foundation of China, (2020YFB0408100) National Key R&D Program of China, (2016ZT06C412) the Program for Guangdong Introducing Innovative and Entrepreneurial Team, (1920001000108) Foshan Science and Technology Innovation Team Project. The authors are thankful to the Deanship of Graduate Studies and Scientific Research at Najran University for funding this work under the Growth Funding Program grant code (NU/GP/SERC/13/728-3).

Author contributions

X.Zeng: conceptual framework, investigation and writing—original draft. Z.Z.: drawing and editing. X.Zheng: review and editing. Y.C.: investigation, writing—review and editing. H.Z.: resources. H.A.: investigation. Z.G.: review and editing. J.H.: conceptualization, resources, supervision.

Declaration of interests

The authors declare no competing interests.