Preparation and performance of electromagnetic wave absorbing foamed ceramics with high closed porosity and gradient SiC distribution

Li, Xiangming; Zhou, Guangyou; Yang, Qi; Zhu, Xiaotao; Ren, Guina; Liu, Li

doi:10.1016/j.ceramint.2019.09.218

Cited by 19 publications

(4 citation statements)

References 18 publications

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“…After three times of vacuum pressure infiltration in silica sol solution, the strength and thermal conductivity of the sintered sample are increased by 63.56% and 21.14%, respectively. The results are consistent with the above analysis [28,29]. The porosity of the samples can be effectively reduced by the filling of silica sol solution into open pores in vacuum pressure infiltration, which can be confirmed by the SEM microstructure in Figure 12.…”

Section: Vacuum Pressure Infiltration Of Silica Sol Solution and High-temperature Sinteringsupporting

confidence: 88%

Fabrication of Natural Flake Graphite/Ceramic Composite Parts with Low Thermal Conductivity and High Strength by Selective Laser Sintering

Chen

et al. 2020

Applied Sciences

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The 3D graphite/ceramic composite prototyping parts directly prepared by selective laser sintering (SLS) were porous, which led to poor strength and low thermal conductivity. In order to obtain low thermal conductivity and high strength, its thermal conductivity and compressive strength were adjusted by changing the mixture powder composition and adding post-processing. The result showed that the addition of silicon powder in the mixture powder could significantly improve the compressive strength and thermal conductivity. The addition of expanded graphite was beneficial to the formation of the closed pores in the matrix, which slightly reduced the compressive strength but significantly reduced the thermal conductivity. The 3D graphite/ceramic composite part showed an order of magnitude improvement in compressive strength (from 1.25 to 13.87 MPa) but relatively small change in thermal conductivity (from 1.40 to 2.12 W·m−1K−1) and density (from 0.53 to 1.13 g·cm−3) by post-processing. Reasonable mixture powder composition and post-processing were determined and realized the possibility of fabricating a 3D graphite/ceramic composite part with low thermal conductivity but high compressive strength. Furthermore, it could be used for the repeated casting of steel castings, and through the comparative analysis of casting defects, the prepared graphite/ceramic composite part was expected to replace water glass sand mold.

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Section: Vacuum Pressure Infiltration Of Silica Sol Solution and High-temperature Sinteringsupporting

confidence: 88%

Fabrication of Natural Flake Graphite/Ceramic Composite Parts with Low Thermal Conductivity and High Strength by Selective Laser Sintering

Chen

et al. 2020

Applied Sciences

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“…To evaluate the EMW absorption ability of the SiOCN ceramic aerogels, the complex permittivity (ε r = ε'−jε''), permeability (μ r = μ'−jμ''), and loss tangent (tan δ) were investigated using vector network analyzers. According to previous studies, [49][50][51][52][53] the real parts (ε' and μ') represent the storage capability and the imaginary parts (ε'' and μ'') represent the loss capability of the electric and magnetic energies, respectively. The ability to convert electromagnetic waves into other forms of energy using loss tangent (tan δ) to represent.…”

Section: Emw Absorption Of Siocn Ceramic Aerogelsmentioning

confidence: 99%

Polysilazane hybrid phenolic resin ceramic aerogels with excellent electromagnetic wave absorption performance

Wang,

Zhu

et al. 2023

J Am Ceram Soc.

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Although various aerogels with electromagnetic wave (EMW) absorbing properties have been extensively explored, the development of aerogels with excellent wave absorption performance, low density, and great heat resistance has still met profound challenges. Herein, polysilazane hybrid phenolic resin aerogels (PRVS aerogels) were prepared using the vinyl addition reaction of polysilazane and cross‐linking reaction between polysilazane and phenolic resin. A SiOCN ceramic aerogel with multistage pore structure was prepared via a simple and quick freeze‐drying method and polymer‐derived ceramic (PDC) methods. The SiOCN ceramic aerogels exhibited low density (0.15–0.27 g/cm3), good heat‐shielding (thermal conductivity in the range of 0.03–0.04 W/(m·K)), and excellent wave absorption performance (i.e., RL was about –31.6 dB@16.48 GHz and EAB was 3.85 GHz when the thickness of the ceramic aerogel was 1.2 mm). Hence, the ceramic aerogel absorbing materials could meet the requirements of “wide absorption bandwidth, strong reflection loss, lightweight and thi thickness”. Moreover, the mechanism of low weight, heat insulation, and wave absorption properties of the aerogels were also investigated. We believe this work is of great significance in ceramic aerogels prepared by traditional polymers, which may provide new opportunities for new ceramic aerogels with applications ranging from EMW absorption to aerospace and information technology.

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“…Li et al fabricated a SiC foam as an EM wave absorber. [97] It was prepared by sintering at air condition with 1200 C-close roaster using Si 3 N 4 and other mineral powders. The as-prepared bulk foam had a density as low as 0.48 g cm À3 .…”

Section: Abrasion Resistancementioning

confidence: 99%

A Novel Strategy in Electromagnetic Wave Absorbing and Shielding Materials Design: Multi‐Responsive Field Effect

et al. 2021

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With the rapid development of 5th Generation Mobile Communication Technology (5G), late-model electromagnetic wave absorbing and shielding (EMAS) materials have proven to be the research emphasis of electromagnetic (EM) wave shelter. Great efforts have been made to optimize EMAS functional materials for diverse EM wavebands. [1] Each range of EM wave bands has a specific application in communication, electrical engineering, or information transmission. [2] For instance, ultrahigh frequency (UHF) EM wave of 0.3 < f < 3 GHz, also known as P/L/S or B/C/D/E band, is applied to television radar air navigation and mobile communication as well as microwave relay systems; the superhigh frequency (SHF) EM wave of 3 < f < 30 GHz, including S/C/X/Ku/K/ Ka-band or F/G/H/I/J/K band, is customarily adopted in digital telecommunication and satellite communication as well as waveguide communication. Moreover, EM waves in other frequency ranges, like terahertz wave and gamma ray, have been widely used in label-free DNA detection, high-temperature superconducting material research, radiographic testing, and even oncotherapy. In these cases, each specific application scenario requires specific EM waves in a specific frequency range, illustrating that EM wave clutters should be absorbed or otherwise shielded. Under these circumstances, developing novel and practical EMAS materials may meet the demands of EM wave science, especially in multifunctional fields.Traditional EMAS materials consist of resistance absorber, [3] dielectric absorber, [4] magnetic medium absorber, [5] and composites based on monomaterials as mentioned earlier, [6] including CuS, [7] MoSe 2 , [8] ferrites and alloys (Co x Fe 3Àx O 4 @C), [9] modified carbons (hollow carbon spheres), [10] etc. In the past decade, 2D transition metal carbides or nitrides, or MXenes, have been prefabricated and naturally applied to EMAS materials synthesis due to their outstanding EM wave loss capacity. [11] Many scholars have devoted themselves to MXene materials and structure design. The electrical conductivity of MXenes can reach 10 3 S cm À1 , leading to extraordinary EM wave shielding property. [12] Many reported MXene absorbers are monolayers, [13] whereas macrostructure design is introduced. Thus, macrodevices, like hollow MXene sphere foam, [14] are synthesized. It is

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Preparation and performance of electromagnetic wave absorbing foamed ceramics with high closed porosity and gradient SiC distribution

Cited by 19 publications

References 18 publications

Fabrication of Natural Flake Graphite/Ceramic Composite Parts with Low Thermal Conductivity and High Strength by Selective Laser Sintering

Fabrication of Natural Flake Graphite/Ceramic Composite Parts with Low Thermal Conductivity and High Strength by Selective Laser Sintering

Polysilazane hybrid phenolic resin ceramic aerogels with excellent electromagnetic wave absorption performance

A Novel Strategy in Electromagnetic Wave Absorbing and Shielding Materials Design: Multi‐Responsive Field Effect

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