共查询到20条相似文献,搜索用时 11 毫秒
1.
Sungjoon Choi Jae-Hyoung You Chris Yeajoon Bon Seung-young Park Sang-Im Yoo 《Ceramics International》2021,47(6):7571-7581
Enhanced microwave absorption properties were successfully achievable from SrFe2-xZnxFe16O27 (SrFe2-xZnxW; x = 0.0, 0.5, 1.0, and 2.0) hexaferrite filler-epoxy resin matrix composites. The composite samples were fabricated with the filler volume fractions (Vf) of 30, 50, 70, and 90%. Compared with fully Zn-substituted SrZn2W composite (x = 2.0), unsubstituted and partially Zn-substituted SrFe2-xZnxW (x = 0.0, 0.5, and 1.0) composites exhibited much higher real and imaginary parts of complex permittivity (εr), which is attributable to higher electron hopping between Fe2+ and Fe3+ ions, and also slightly higher real and imaginary parts of complex permeability (μr) due to higher saturation magnetization (Ms). Among all samples, a 2.8 mm-thick SrFe1·5Zn0·5W (x = 0.5) composite with the Vf of 90% exhibited the most appropriate for application in the region of 3.4–3.8 GHz, having the minimum reflection loss (RLmin) of ?46 dB at 3.6 GHz with the bandwidth of 0.43 GHz (3.38–3.81 GHz) below ?10 dB, while a 2.15 mm-thick SrFeZnW (x = 1.0) composite with the Vf of 70% showed the most appropriate for application in the region of 5.9–7.1 GHz, possessing the RLmin value of ?23.7 dB at 6.6 GHz with the bandwidth of 1.38 GHz (5.85–7.23 GHz) below ?10 dB. Consequently, partially Zn-substituted SrW-type hexaferrites are very promising microwave absorbers for 5G mobile communications in the Ku band (0.5–18 GHz). 相似文献
2.
《Ceramics International》2021,47(19):27496-27502
Composition and structural design play a very influential role in the microwave absorption (MA) manipulation of ferrite/carbon composites. Here, by carefully choosing the dimensionality of the bio-carbon materials, the interfacial geometries and MA properties of ferrite/bio-carbon composites have been controlled effectively. The one dimensional (1D), two dimensional (2D), and three dimensional (3D) biomass-based carbon materials decorated with ZnFe2O4 (ZFO) particles were obtained respectively from carbon fibers (1D), tree leaves (2D), wheat straw (2D), peanut shell (3D) and orange peel (3D) by a simple two-step synthesis method. With increasing the bio-carbon's dimensionality from 1D, 2D to 3D, the ferrite/carbon composite's MA properties are promoted and the minimum reflection loss is enhanced from −9 dB to −45 dB. By changing the ZFO/3D-bio-carbon samples' thickness, a broad absorption range from 4 to 18 GHz can be covered. Moreover, the effective absorption bandwidth for ZFO/3D-bio-carbon can be modified up to 7.1 GHz, which covers the whole Ku band. These observations identified the important roles of the ferrite/carbon interface and dimensionality of carbon materials and provided an effective and low-cost route to design microwave absorption materials based on biomass-industrial waste composites. 相似文献
3.
Yupeng Wei Jingpeng Lin Tiantian Jiang Linqi Li Kangyou Zhong Junwei Zhang Yong Peng 《Ceramics International》2021,47(6):7937-7945
Core-shell C/NiP microfiber composites were fabricated via electroless plating in this work. Their microstructure and electromagnetic properties were adjusted by annealing treatment and different phosphorus (P) content in the NiP coating. The C/NiP microfibers composites with 6 wt % P content in the NiP coating annealed at 300 °C remarkably owns ?46.7 dB strong reflection loss at 10.0 GHz with the thickness of 2.0 mm, and the effective bandwidth (RL ≤ ?10 dB) reaches 8.1 GHz (3.1–11.2 GHz). This work shows that the annealing conditions and different P concentrations in the coating layers for C/NiP microfibers composites are the effective way to optimize the electromagnetic wave absorption performance. 相似文献
4.
Xiongzhang Liu Hui Luo Jiaji Yang Xian Wang Zewen Qu Heng Luo Rongzhou Gong 《Ceramics International》2021,47(4):4475-4485
TiB2–MgO microwave absorbing materials with TiB2 as the absorber, MgO as the matrix are prepared by spark plasma sintering (SPS). The influences of commercial TiB2 content and sintering temperature on dielectric and microwave absorption (MA) properties are studied. Besides, to optimize the MA performance, TiB2–MgO composite containing TiB2 synthesized by the carbonthermal process is prepared. Meanwhile, its high-temperature dielectric and MA properties are investigated. Indeed, both the commercial TiB2 content and sintering temperature play key roles in dielectric and MA properties, as they reaching 8 wt% and 1400 °C, the composite presents the optimal MA performance. For composite with synthetic TiB2 as the absorber, the temperature has a positive effect on dielectric and MA properties. The enhanced high-temperature MA properties with minimum reflection loss (RLmin) of ?52.11 dB at 1.6 mm under 500 °C and effective absorption bandwidth (EAB, RL < ?5 dB) of 4.2 GHz at 1.4–1.6 mm under 800 °C are obtained, which is mainly attributed to the temperature-dependent interfacial polarization compared to the temperature-insensitive conductivity. The excellent mechanical properties (flexural strength = 212.48 MPa), thin absorbing layer (d < 2 mm), enhanced thermal stability and high-temperature MA properties indicate that the TiB2–MgO composites can be considered as new candidates for high-temperature structure microwave absorbing materials. 相似文献
5.
Xiaohu Ren Xilou Pu Hongfeng Yin Yun Tang Hudie Yuan Huiqing Fan 《Ceramics International》2021,47(9):12122-12129
Hexagonal barium ferries is a promising and efficient microwave (MW) absorbing material, but the low dielectric loss and poor conductivity have limited their extensive applications. In this work, a simple tactic of coating conductive polymer PANI on hexaferrite BaCo2Fe16O27 is presented, wherein the dielectric properties are customized, and more significantly, the electromagnetic loss is greatly enhanced. As displayed from structural characterizations, PANI were coated equably on the surface of hexaferrite grains by an in-situ polymerization process. The outcomes exhibit the as-prepared PANI@hexaferrite composite has remarkable electromagnetic wave absorption capacity. When the thickness is 6.0 mm, the minimal RL of ?40.4 dB was achieved at 2.9 GHz. The effective absorption bandwidth (RL < ?20 dB) of 0.65 GHz, 0.53 GHz, 0.65 GHz, 0.52 GHz, 0.46 GHz and 0.39 GHz was achieved separately when the thickness ranges from 4 to 9 mm. The highly efficient MW absorbing performance of PANI@hexaferrite composite were the consequence of multiple loss mechanisms and perfect impedance matching. It is demonstrated that the PANI@hexaferrite composite with excellent MW absorption performance is expected to be potential MW absorbers for extensive applications. 相似文献
6.
G. Logesh Ummen Sabu C. Srishilan Mohammed Rashad Andrews Joseph K.C. James Raju M. Balasubramanian 《Ceramics International》2021,47(16):22540-22549
The hybrid network of Si3N4 whiskers and conducting carbon fiber has great potential for microwave absoprtion applications. The high electrical conductivity of the carbon fiber helps to transform the microwave transparent Si3N4 into microwave absorbing materials. Herein, the microwave absorption performance of 5–20 vol % of carbon fiber reinforced reaction bonded Si3N4 (Cf-RBSN) composites have been discussed in detail. The Cf reinforcement tuned the X-band dielectric properties of the RBSN composites. The 5 vol % Cf-RBSN composite exhibit a minimum reflection loss (RLmin) of ?36.16 dB (99.998% microwave absorption) at 11.89 GHz and a high specific reflection loss of 920 dB. g?1 for 5.9 mm thickness, while 20 vol % Cf-RBSN composites resulted in RLmin of ?22.86 dB at 11.56 GHz with a low thickness of 1.5 mm. Thus, the superior microwave absorption performance of the prepared lightweight composites results from the multiple interfacial polarization, dipole polarization, and conduction loss due to the 3D network of interconnected Si3N4 whiskers and Cf. 相似文献
7.
《Ceramics International》2022,48(17):24803-24810
SiC fiber reinforced ceramic matrix composites (SiCf-CMCs) have been widely used as structural-functional materials at high temperatures. However, their mechanical and electromagnetic wave (EMW) absorbing properties will deteriorate due to high-temperature oxidation. Therefore, unique sandwich structure, consisting of inner Si3N4 impedance layer, middle porous SiOC loss layer and dense oxidation-resistant Si3N4 layer, was proposed to enhance multiple material properties in oxidation environment. Herein, SiCf/Si3N4–SiOC–Si3N4 composites was fabricated by alternating chemical vapor infiltration (CVI) and polymer infiltration pyrolysis (PIP) methods. For these composites, SiC fiber is used as both reinforcing phase and electromagnetic (EM) absorber. CVI Si3N4 matrix was distributed in inner and outer layer of the SiCf/Si3N4–SiOC–Si3N4 composites. While inner Si3N4 layer between BN interphase and SiOC matrix forms nano-heterogeneous interphase to consume EM energy and enhance mechanical properties of composites, outer dense and oxidation-resistant CVI Si3N4 coating serves to maintain properties. PIP SiOC matrix exhibits porous structure that can effectively deflect cracks and achieve multiple scattering of EMW. SiCf/Si3N4–SiOC–Si3N4 composites with sandwich structure demonstrated excellent EMW absorbing properties and mechanical performance in high-temperature oxidation environments. 相似文献
8.
Haonan Gong Shujuan Tan Jing Zheng Kangsen Peng Yanting Zhang Yunjia Hu Songhan Duan Guoyue Xu 《Ceramics International》2021,47(9):12389-12396
In this work, flake-shaped FeCo/BaFe12O19 composites were successfully prepared via a facile two-step process involving ball milling and sol-gel treatment. Compared with commonly used FeCo alloys, FeCo/BaFe12O19 composite material can achieve remarkable microwave absorption performance, and this is largely because of the flake-shaped structure and dielectric relaxation processes. Furthermore, changing mass fractions of BaFe12O19 enable flexible control of applicable frequency ranges of FeCo/BaFe12O19 composites. It was found that when the BaFe12O19 mass fraction is as high as 20%, minimum reflection loss can reach ?51.22 dB with effective loss of < –10 dB and effective bandwidth of 6.24 GHz even at a thin thickness of 1.45 mm. It is highly believed that these significant achievements will arouse interest from researchers for further practical exploration of microwave absorbers. 相似文献
9.
《Ceramics International》2022,48(13):18567-18578
In this study, SiC interphase was prepared via a precursor infiltration-pyrolysis process, and effects of dipping concentrations on the mechanical, high-temperature dielectric and microwave absorption properties of the SiCf/SiC/Mu composites had been investigated. Results indicated that different dipping concentrations influenced ultimate interfacial morphology. The SiC interphase prepared with 5 wt% PCS/xylene solution was smooth and homogeneous, and no bridging between the fiber monofilament could be observed. At the same time, SiC interphase prepared with 5 wt% PCS/xylene solution had significantly improved mechanical properties of the composite. In particular, the flexural strength of the composite prepared with 5 wt% PCS/xylene solution reached 281 MPa. Both ε′ and ε′′ of the SiCf/SiC/Mu composites were enhanced after preparing SiC interphase at room temperature. The SiCf/SiC/Mu composite prepared with 5 wt% PCS/xylene solution showed the maximum dielectric loss value of 0.38 at 10 GHz. Under the dual action of polarization mechanism and conductance loss, both ε′ and ε′′ of the SiCf/SiC/Mu composites enhanced as the temperature increased. At 700 °C, the corresponding bandwidth (RL ≤ ?5 dB) of SiCf/SiC/Mu composites prepared with 5 wt% PCS/xylene solution can reach 3.3 GHz at 2.6 mm. The SiCf/SiC/Mu composite with SiC interphase prepared with 5 wt% PCS/xylene solution is expected to be an excellent structural-functional material. 相似文献
10.
Intrinsic dielectric properties and tuning conductivity play important roles in microwave absorption. Novel multi-interfaced ZnSnO3@ fine ash (ZSFA) composite was successfully synthesized by coating cube-like ZnSnO3 particles with highly graphitized gasification fine ash. After hydrothermal reaction and Ostwald ripening process, fine ash was tightly wrapped around the assembly of ZnSnO3 particles. Related electromagnetic parameters and dielectric dissipation ability were discussed with different mass additions. Owing to the strong polarization relaxation, special conductive network, and multi-interface structural design, the as-synthesized ZSFA exhibited adjustable dielectric loss behaviors and efficient microwave absorption ability. When 50% mass added, the maximum reflection loss value of the obtained ZSFA-2 is ?47.8 dB at 2.5 mm thickness, showing the enhanced dielectric loss ability. Meanwhile, the widest effective absorption bandwidth (RL ≤ ?10 dB) can cover 7.0 GHz (11.0–18.0 GHz) at a thickness of only 2.2 mm, which included the entire Ku band. This unique pure dielectric composite exhibited high-performance electromagnetic wave attenuation property and broadband frequency response, thereby providing a new approach to the production of a superior microwave absorber. 相似文献
11.
Xiaojun Chen Hongyang Liu Dechao Hu Huaqing Liu Wenshi Ma 《Ceramics International》2021,47(17):23749-23761
With the blossom of information industry, electromagnetic wave technology shows increasingly potential in many fields. Nevertheless, the trouble caused by electromagnetic waves has also drawn extensive attention. For instance, electromagnetic pollution can threaten information safety in vital fields and the normal function of delicate electronic devices. Consequently, electromagnetic pollution and interference become an urgent issue that needs to be addressed. Carbon nanotubes (CNTs) have become a potential candidate to deal with these problems due to many advantages, such as high dielectric loss, remarkable thermodynamic stability, and low density. With the appearance of climbing demands, however, the carbon nanotubes combining various composites have shown greater prospects than the single CNTs in microwave absorbing materials. In this short review, recent advances in CNTs-based microwave absorbing materials were comprehensively discussed. Typically, we introduced the electromagnetic wave absorption mechanism of CNTs-based microwave absorbing materials and generalized the development of CNTs-based microwave absorbers, including CNTs-based magnetic metal composites, CNTs-based ferrite composites, and CNTs-based polymer composites. Ultimately, the growing trend and bottleneck of CNTs-based composites for microwave absorption were analyzed to provide some available ideas to more scientific workers. 相似文献
12.
Liang Zhou Junxiao Yan Julong Huang Hongbo Wang Xingang Wang Zhenjun Wang 《Ceramics International》2021,47(6):7831-7836
Here in, the effects of FeSiAl particle size on the dielectric and microwave absorption properties of FeSiAl/Al2O3 composites were studied. FeSiAl/Al2O3 composites containing 18–25 μm, 25–48 μm, and 48–75 μm FeSiAl particles were prepared by hot-pressed sintering based on uniformly mixed FeSiAl and Al2O3 powders. Results show that the real permittivity and the imaginary permittivity are significantly promoted with increasing FeSiAl particle size, which is ascribed to the enhanced interfacial polarization and conductance loss. In addition, the favorable matching impedance and suitable attenuation coefficient enabled the composite containing 25–48 μm FeSiAl powder to show a minimum reflection loss of ?34.4 dB at 11.7 GHz and an effective absorption bandwidth (<-10 dB) of 1.4 GHz in 11.0–12.4 GHz, when the thickness is 1.1 mm. By adjusting the thickness to 1.4 mm, the effective absorption bandwidth of the composite reaches a maximum value of 2.0 GHz in the 8.3–10.3 GHz range, indicating tunable, strong, and highly efficient microwave absorption performance. 相似文献
13.
《Ceramics International》2021,47(18):25986-25996
Being in the strategic direction of next-generation absorbers, multifunctional microwave absorbing materials possess great application value in military and commercial fields. However, the stringent requirements for performance necessitate the combination of multiple functions in such type of composites, which is still a challenge. This work aims to develop a foam-type absorber composed of multi-dimensional organic and inorganic materials, in which reduced graphene oxide sheets and polyvinyl alcohol membranes serve as the framework and crosslinker to form a three-dimensional skeleton. Meanwhile, SiC nanofibers as a reinforcing component can effectively suppress the over-stacking of reduced graphene oxide and enhance the conductivity and mechanical strength of cell walls. Among the remarkable microwave absorbing properties of the obtained foam, there are the ultra-light (9.85 mg cm-3), broadband (7.04 GHz), and strong absorption (reflection loss of -61.02 dB), all combined in the ultra-thin (2.5 mm). In addition, the foam possesses superelastic and excellent heat-insulating characteristics that ensure shock resistance, heat preservation, and infrared stealth. The remarkable versatility benefits from the porous structure, as well as from the synergistic effect of multi-dimensional organic and inorganic constituents of the foam. Therefore this study lays the foundation for the design of new-generation microwave absorbers with broad application potential. 相似文献
14.
Hui Gao Fa Luo Qinlong Wen Shichang Duan Wancheng Zhou Dongmei Zhu 《Ceramics International》2018,44(6):6010-6015
Fiber-reinforced ceramic matrix composites have excellent mechanical and microwave absorption properties, but still present considerable challenges. We prepared a SiCf/mullite-SiO2 composite (composite A) and a SiCf/Al2O3-SiO2 composite (composite B) by a precursor infiltration and sintering (PIS) process. Compared with the composite B, the composite A was easily densified. The flexural strength of the composite A reached 216 MPa, whereas that of the composite B was 159 MPa. The imaginary part of permittivity for composites A and B, which was determined by the contents of matrix and porosity, varied in the range of 2.5–3.5 and 3.6–5, respectively. The microwave absorption properties of the composite A were significantly enhanced in the range of 8.2–12.4 GHz. The results indicate that an optimal reflection loss of ?44 dB was reached at 12 GHz with a thickness of 2.9 mm for the composite A. These SiC fiber-reinforced oxide matrix materials have promising applications in microwave absorption, especially at high temperatures. 相似文献
15.
Cheng Chen Limei Pan Senchuan Jiang Shuang Yin Xiaoyun Li Jingxian Zhang Yongbao Feng Jian Yang 《Journal of the European Ceramic Society》2018,38(4):1639-1646
Herein, a novel microwave absorbing material with Graphene nanosheets (GNSs) as microwave absorbing filler and magnesia (MgO) as matrix were prepared by hot-pressing sintering. The composites were highly dense with a homogeneous distribution of GNSs. Electrical conductivity, dielectric and microwave absorption properties in X-band were investigated. The results revealed that the electrical conductivity of the GNSs/MgO composites showed a typical percolation-type behavior with a percolation threshold of 3.34 vol%. With GNSs content increased to 3 vol%, the real permittivity, imaginary permittivity and dielectric loss tangent of the composites increased from ~9, ~0 and ~0 to 26–43, 23–28 and 0.55–0.96, respectively. By adjusting the GNSs content, thickness and frequency, the 2.5 vol% GNSs/MgO composite shows the minimum reflection loss of ?36.5 dB at 10.7 GHz and the reflection loss below ?10 dB (90% absorption) ranges from 9.4 to 11.4 GHz with 1.5 mm thickness, exhibiting excellent microwave absorption properties. 相似文献
16.
《Ceramics International》2022,48(24):36238-36248
Cf/SiC composite is an excellent structural and functional material, silicon carbide nanowires (SiCnws) are not only a toughening material but also a great application in the field of microwave absorption. In this study, SiCnws are grown on the surface of carbon fiber (Cf) by polymer impregnation and pyrolysis, and the SiC matrix was prepared by chemical vapor osmosis method. The SiCnws are introduced to enhance the mechanical and microwave absorption properties simultaneously. After 3 impregnations, the flexural strength of the composite was 107.35 ± 10 MPa. When the thickness is 1.86 mm, the minimum reflection loss value is ?41.08 dB, and the effective absorption bandwidth (RL ≤ ?10 dB) is 3.86 GHz. Furthermore, the microwave absorption mechanism of the material is discussed. This work provides a new method to prepare lightweight, stable and high-performance microwave absorption materials, and these materials are expected to be used in high temperature environments. 相似文献
17.
Wei Zhou Rui-ming Yin Lan Long Heng Luo Wei-da Hu Yan-hong Ding Yang Li 《Ceramics International》2018,44(11):12301-12307
Si3N4 ceramics modified with SiC nanofibers were prepared by gel casting aiming to enhance the dielectric and microwave absorption properties at temperatures ranging from 25?°C to 800?°C within X-band (8.2–12.4?GHz). The results indicate that the complex permittivity and dielectric loss are significantly increased with increased weight fraction of SiC nanofibers in the Si3N4 ceramics. Meanwhile, both complex permittivity and dielectric loss of SiC nanofibers modified Si3N4 ceramics are obviously temperature-dependent, and increase with the higher test temperatures. Increased charges mobility along conducting paths made of self-interconnected SiC nanofibers together with multi-scale net-shaped structure composed of SiC nanofibers, Si3N4 grains and micro-pores are the main reason for these enhancements in dielectric properties. Moreover, the calculated microwave absorption demonstrates that much enhanced microwave attenuation abilities can be achieved in the SiC nanofibers modified Si3N4 ceramics, and temperature has positive effects on the microwave absorption performance. The SiC nanofibers modified Si3N4 ceramics will be promising candidates as microwave absorbing materials for high-temperature applications. 相似文献
18.
《Ceramics International》2022,48(14):19709-19719
A carbon-silica nanomaterial for electromagnetic wave (EW) absorption was synthesized using a modified one-pot method. The unique hydrolysis-polymerization process forms a SiO2@SiO2/Carbon@Carbon core-shell structure. The growth process of the material was studied by transmission electron microscope (TEM) and thermogravimetric analysis (TGA). Nanoparticles were successfully synthesized with a core-shell structure after 6 h of reaction, and the composite material showed excellent EW absorption performance with a thickness of 3.8 mm. The minimum reflection loss (RLmin) was ?56.3 dB, and the broadest effective absorption bandwidth (EAB) (RL ≤ 10 dB, 90% absorption) covered 5.15 GHz (12.48–17.63 GHz) with 1.8 mm of thickness. There is no significant difference in the EW absorption performance with increasing reaction time. Thus, this study provides a method for synthesizing EW-absorbing materials with shorter reaction time, simpler process, and excellent absorption properties, possibly a candidate for further application. 相似文献
19.
Jie Dong Wancheng Zhou Yuchang Qing Lu Gao Shichang Duan Fa Luo Dongmei Zhu 《Ceramics International》2018,44(12):14007-14012
Carbon black (CB) with contents of 5.5?wt% and 15?wt% filled quartz glass fiber reinforced polyimide (SiO2f/PI) composite were designed and prepared. A double-layer absorbing material was designed using the two composites materials as a matching layer and an absorption layer, respectively. The microwave absorption property of single-layer and double-layer composites is calculated according to transmission line theory. The results show that the microwave absorbing property of double-layer composite is better than that of single-layer at the same thickness. When the 5.5?wt%CB doped SiO2f/PI composite is used as the matching layer with a thickness of 0.7?mm and 15?wt%CB doped SiO2f/PI composite is used as the absorption layer with a thickness of 0.9?mm, the RL (reflection loss) of the composite reaches a minimum value of ?46.18?dB at 16.07?GHz. Meanwhile, the bandwidth of RL?≤??5?dB is 5.87?GHz and the bandwidth of RL?≤??10?dB is 3.95?GHz. 相似文献
20.
《Ceramics International》2020,46(3):3166-3176
A large number of studies had shown that the morphology of the sample had a significant effect on the microwave absorption properties and catalytic activity of the sample. Manganese dioxide with different morphologies was synthesized by hydrothermal method through different precursors. The effects of sample morphology and microwave absorption properties on the catalytic activity of the sample in conventional thermal and microwave fields were studied. The results indicated that compared with the conventional thermal field, the catalytic activity of the samples in microwave field were obviously improved, and the activation energy of the reaction were decreased. Compared with the conventional thermal field, the conversion of toluene in microwave thermal field of MnO2(Ac), MnO2(S) and MnO2(N) increased by 59%, 42% and 12%, and the mineralization rate increased by 36%,11% and 2%, respectively, when the catalytic temperature was 150 °C. Compared with the traditional thermal field, the activation energy of the sample MnO2(Ac) in the microwave field was reduced by 88.3 KJ. A series of characterization results showed that the sample MnO2(Ac) had good catalytic activity in the microwave field was due to: MnO2(Ac) had proper microwave absorption properties, large amount of surface functional groups, large specific surface area and rich pore structure. The analysis results of electromagnetic parameters showed that: the reason that the sample MnO2(Ac) had good microwave absorption performance was that the MnO2(Ac) had proper impedance matching, high attenuation constant and Debye dipole relaxation effect. 相似文献