SENSORS AND ACTUATORS A-PHYSICAL
·
2024
·
IF 4.1
Xingang Luan,Qinghua Zhao,Xuefei Sun,Shaomin Gu,Xichao Dong,Laifei Cheng,Ralf Riedel
Aiming at the lack of stable and reliable electrode materials for high temperature wireless sensors , a solution was proposed to use SiBCN ceramic as thin film electrode. To optimize the conductivity of SiBCN coatings, different conductive fillers were incorporated into the precursor solution to prepare conductive SiBCN coatings and the relationship between the coating process parameters, surface morphology and conductivity was established. The results show that the microstructure of the composite can be adjusted in terms of the HfB 2 /CNT ratio to optimize the electrical conductivity . HfB 2 and CNTs are evenly distributed in the coating by adding dispersants and ground SiBCN self-fillers. The electrical conductivity of SiBCN coatings can be greatly enhanced by adding HfB 2 and CNTs fillers. Integrating conductive fillers such as HfB 2 and CNTs can form a diafiltration path and the resistivity of the prepared coating has been determined to be as low as 0.13 ± 0.01 Ω m. The conductivity did not necessarily increase with an increasing amount of fillers. Adding a balanced amount of filler particles to the ceramic matrix is the requirement for optimizing the electrical conductivity of the coating.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Xingang Luan,Qinghua Zhao,Shaomin Gu,Xichao Dong,Laifei Cheng,Ralf Riedel
Wireless passive sensors based on surface acoustic wave (SAW) provide a good solution for the measurement demand under high temperature and harsh conditions. SiBCN ceramics have excellent mechanical properties at high temperature and semiconductor behavior, making them potential for electrode of SAW sensors. To achieve the target conductivity, a series of SiBCN and SiNiBCN coatings are prepared by polymer derived ceramics (PDC) method and the influence of microstructure on the conductivity of the coatings is discussed. The results show that the conductivity of the SiBCN coatings is affected by both the content of free carbon and the degree of graphitization. The introduction of Ni leads to the formation of Ni 2 Si conductive microcrystals at lower temperatures and catalyzes the graphitization of the carbon phase, so that the SiNiBCN coatings show lower electrical resistivity. The amount of the metal conductive phase and the graphitization degree of the carbon phase increase with the pyrolysis temperature, resulting in decrease of the SiNiBCN coatings resistivity.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
KEY ENGINEERING MATERIALS
·
2012
·
IF 0
Si Hui Wang,He Yun Wang,Fan Xing Meng,Ya Li Li
Abstract: The introduction of metal atoms into SiBCN network allows the development of novel high temperature ceramics and functional ceramics. In this work, cerium (Ce) containing polyborosilazane (PBSZ) is synthesized through substitution and polymerization reactions. Ce atoms are incorporated into PBSZ through the lithium replacement of H in PBSZ followed by Ce replacement of lithium. The chemical structure of the PBSZ and as-synthesized Li containing PBSZ are analyzed by Fourier transform infrared (FTIR) shows that the bands at 598 and 1183 cm-1 which can be assigned to Li-N and Si-N-Li stretching. It is suggested that lithium is incorporated into PBSZ. PBSZCe is transformed into SiBCNCe ceramic by pyrolysed in argon. Scanning electron microscope shows that the SiBCNCe ceramics are porous on the surface and corallike in the section. The chemical bondings of SiBCNCe ceramics are BN, the BN, SiC and Si3N4 characterized by X-ray photoelectron spectroscopy.
研究领域:
材料科学
·
无机化学
✓ 已验证
DOI
COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Quan Yang,Pingan Chen,Xiangcheng Li,Yingli Zhu
To achieve strong electromagnetic wave absorbing properties, it is important to have good impedance matching, moderate electrical conductivity , and high polarization loss, particularly at low frequency. However, meeting these requirements for polymer-derived ceramics remains challenging. This paper proposes a simple approach to addressing this challenge by adjusting the crystallinity and defects of SiBCN ceramics. The addition of Sm as a catalyst and tailored heating temperatures were used to create SiBCN ceramics with adjustable crystallinities and defective nanograins. The controlled crystallinity provided good impedance matching, while the tailored defective nanograins offered high polarization loss. The combination of these factors results in high-performance electromagnetic wave absorption, with the SiBCN ceramics achieving a minimum reflection loss of −59.13 dB at 3.6 GHz and an effective attenuation bandwidth of 6.87 GHz with a thickness of 2.22 mm. This study provides an effective strategy for the design and fabrication of strong EMW absorbing materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2020
·Vol. 104
·期 4
·1772-1784
·
IF 3.502
Jinxue Ding,Fengbo Chen,Jianxin Chen,Jin Liang,Jie Kong
Demand for high-performance electromagnetic (EM) wave absorbing materials with high-temperature resistance is always urgent for application in a harsh environment. In this contribution, two-dimensional material, Ti 3 C 2 T x MXene, was introduced into a hyperbranched polyborosilazane. After pyrolyzation, the as-prepared TiC/SiBCN ceramics present excellent EM wave absorption in X-band. The TiC nanograins appearing after annealing provide multilevel reflection and interface polarization. Dipole polarization formed at interface defects, in company with interfacial polarization, also makes a great contribution to enhanced EM wave absorption. The TiC/SiBCN nanocomplex prepared with 5 wt% Ti 3 C 2 T x MXene possesses a minimum reflection coefficient of −45.44 dB at 10.93 GHz and abroad bandwidth 8.4 and 12.4 GHz, almost covering the entire X-band. Tuning the thickness in the range of 2.35-2.54 mm, the effective absorption band can achieve the entire X-band. And the EM wave absorbing performance has been maintained to a large extent at 600°C with the minimum reflection coefficient of −26.12 dB at 12.13 GHz and the effective absorption bandwidth of 2 GHz. Last but not the least, TiC/SiBCN ceramics offer a good thermal stability in argon as well as in air atmosphere, making it possible to serve in high-temperature detrimental environments. This study is expected to provide a new perspective for the design of high-performance absorbing materials that are able to be used in harsh environments, especially in high temperatures.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Pingan Chen,Tao Peng,Quan Yang,Yingli Zhu,Fu Chen,Mengke Qiao,Xiangcheng Li
Strong attenuation capability and good impedance matching are necessary conditions for high-performance electromagnetic wave (EMW) attenuation materials, which are difficult to balance in the polymer-derived ceramics (PDCs) preparation process. In this work, the dielectric loss phase and wave-transparent phase are simultaneously obtained in SiBCN ceramics, endowing a strong EMW absorbing capability. The results show that the transformation of Si 3 N 4 to SiC could be controlled to achieve coexistence in SiBCN ceramics. The Si 3 N 4 improves the impedance matching characteristics, while SiC and the corresponding heterogeneous interfaces enhance the polarization loss capability. Furthermore, the graphite strips construct a three-dimensional conductive network to improve the conductive loss capability. As a result, the minimum reflection loss reaches -54.24 dB at 15.04 GHz, and the effective absorption bandwidth is 7.48 GHz with a thickness of 1.72 mm, covering the whole Ku band. The excellent EMW absorption capability of SiBCN ceramics can be attributed to the synergistic function of Si 3 N 4 and SiC, which provides a novel strategy for the preparation of ultra-thin and strong EMW attenuating materials with broadband.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2017
·
IF 3.454
Daxin Li,Zhihua Yang,Dechang Jia,Xiaoming Duan,Yu Zhou,Dongli Yu,Yongjun Tian,Zihuan Wang,Yinglong Liu
Nanocrystalline SiBCN monoliths with the same Si/C/N mole ratio and various boron additions ranged from 0 to 3.0 mol were prepared by mechanical alloying plus reactive hot pressing methods. Correction of boron content and microstructural/morphological evolution was investigated in detail by XRD , SEM, TEM and STEM-EDX structure characterization. Except for SiC and BN(C), boron addition contributes to B x C formation. Besides, boron addition promotes the crystallization of SiC, leading to the formation of poor crystallinity of spherical structures in inner SiC. Furthermore, boron addition significantly promotes the grain growth of SiC and B x C and therefore increases the relative volume ratios of B x C/BN(C) and B x C/SiC. Amorphous-like BN(C) changes to belt-like structures as boron addition increases. The new formed B x C effectively contributes to the improvement of Vicker’s hardness while pull-out of BN(C) belt-like structures benefits the fracture toughness.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Qingqing Chen,Daxin Li,Zhihua Yang,Dechang Jia,Yu Zhou,Ralf Riedel
Tris(dichloromethylsilylethyl)borane is a compound containing a B–C bond and Cl and H elements. Herein, we propose a novel method to synthesize polyborosilazanes using tris(dichloromethylsilylethyl)borane and boron trichlorosilane as boron sources and hexamethyldisilazane as a nitrogen source. The microstructure and chemical composition of the as-synthesized polyborosilazanes and as-annealed SiBCN ceramics were investigated using Fourier transform infrared spectroscopy , nuclear magnetic resonance spectroscopy , Raman spectroscopy , scanning electron microscope, and transmission electron microscope methods. The organic precursors were converted entirely into inorganic ceramics at 800 °C, and the ceramic yield of the polyborosilazanes was 88% at 1000 °C. SiBCN ceramics with irregular shapes contained chemical bonds of B–N, Si–N, and Si–C at 1500 °C and retained an amorphous structure below 1600 °C. After the first cycle, the fabricated SiBCN ceramic anodes exhibited a reversible capacity of 261.3 mA h/g, which was 2.6 times that reported in the literature (101 mA h/g). The discharge capacity decreased to 157.6 mA h/g after 30 cycles. The satisfactory electrochemical performance of the resulting SiBCN ceramic anodes can be attributed to the formation of conductive carbon species favoring the transport properties of lithium ion .
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Junpeng Jiang,Liwen Yan,Jiangtao Li,Yunjia Xue,Chensi Zhang,Xiaoxia Hu,Anran Guo,Haiyan Du,Jiachen Liu
Owing to tunable dielectric properties, light weight and high porosity, polymer-derived SiBCN ceramic aerogels possess significant application prospects in electromagnetic wave (EMW) absorption and thermal insulation. However, due to inadequate oxidation resistance, the structural collapse and performance deterioration of SiBCN aerogels will easily occur in high-temperature aerobic environments, limiting their application. Herein, to address this issue, a novel and straightforward strategy based on typical polymer-derived-ceramic (PDC) aerogel method and impregnation with boehmite sol was proposed for synthesizing SiBCN/Al 2 O 3 composite ceramic aerogels. The microstructure, phase composition, thermal insulation, oxidation resistance and EMW absorption properties of SiBCN/Al 2 O 3 ceramic aerogels were investigated. The resulting SiBCN/Al 2 O 3 composite aerogel demonstrates superior high-temperature structural stability, exhibiting an ultra-low linear shrinkage of only 6.5 % following heat treatment at 1200 °C for 2 h in air. Additionally, the composite aerogel shows a low thermal conductivity of 0.039 W/mK and a low density of 0.112 g/cm 3 . The SiBCN/Al 2 O 3 composite aerogel, composed of dielectric SiBCN, conductive free carbon, and insulating alumina, demonstrates outstanding EMW absorption properties with a minimum reflection loss of −48.6 dB and an effective bandwidth of 5.8 GHz. The enhanced microwave absorption performance is mainly attributed to the improved impedance matching, multiple reflection, and enhanced interfacial polarization resulting from the introduction of Al 2 O 3 . Given prominent oxidation resistance, thermal insulation and EMW absorption properties, the SiBCN/Al 2 O 3 composite aerogel paves the way for developing microwave absorption and thermal insulation integrated material in high-speed vehicles.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Junpeng Jiang,Yunjia Xue,Jiangtao Li,Chensi Zhang,Xiaoxia Hu,Liwen Yan,Anran Guo,Haiyan Du,Jiachen Liu
Polymer-derived SiBCN ceramic aerogels have attracted extensive attention in recent years due to the excellent electromagnetic wave absorption and thermal insulation properties. With these merits, SiBCN aerogels are promising for the application of high-speed vehicles requiring thermal and electromagnetic shielding. However, the brittleness and poor mechanical property of SiBCN aerogel seriously hinder its practical applications. In this paper, SiBCN/SiBCN nf composite ceramic aerogels with enhanced mechanical property were prepared by combining electrospinning technique with simultaneous pyrolysis process of polyborosilane (PBS) fibers and precursor aerogels. The effect of varying fiber content on the density, mechanical property, thermal insulation as well as microwave absorption performance of the composite aerogel was investigated. In addition, the underlying toughness mechanism of the SiBCN/SiBCN nf composite ceramic aerogel was elucidated. The compressive strength of the SiBCN/SiBCN nf composite aerogel increased from 0.29 MPa to 1.62 MPa. Importantly, while the mechanical strength of the composite aerogel increased by about 5.5 times, SiBCN/SiBCN nf aerogel still exhibits low density of 0.105 g/cm³, low thermal conductivity of 0.048 W/mK and a minimum reflection loss (RL min ) of −20 dB. Owing to the integration of electromagnetic wave (EMW) absorption and thermal insulation properties, SiBCN/SiBCN nf aerogels pave the way for the construction of thermal and electromagnetic shielding material for high-speed vehicles.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Wenxia Zhu,Xiaohui Xia,Yukun Zheng,Huiming Ji,Dong Su
Precursor derived SiBCN ceramic is considered as promising materials for advanced electromagnetic interference (EMI) shielding. Here, the graphene nanosheet (GNS) aerogel via high-temperature graphitization was used as conductive network for constructing GNS/SiBCN nanocomposites through polyborosilazane (PBSZ) precursor infiltration and pyrolysis. The graphitization process of GNS aerogels increases the electrical conductivity of GNS/SiBCN nanocomposites from 105 to 1168 S·m −1 , and achieves an improved EMI shielding effectiveness (SE Total ) from 24.1 to 39.3 dB. The SiBCN protection endows the nanocomposite with good oxidation resistance at 800 °C in air and high-temperature stability at 1400 °C in Ar. Moreover, the porous GNS/SiBCN nanocomposite with density of 0.11 g·cm −3 was attained by adjusting the PBSZ content of 10 % during the infiltration, further exhibiting a high SE Total of 32.7 dB and a high specific SE Total of 297 dB·g −1 ·cm 3 . Therefore, it’s an ideal route to develop lightweight EMI shielding materials used in high-temperature environment.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2024
·
IF 11.2
Zhen Yu,Mingwei Ma,Ziyu Liu,Zhengyi Zhang,Chunjia Luo,Tiantian Zhang,Jie Kong
Polymer-derived ceramics (PDCs) is a promising way to prepare ceramic-based electromagnetic functional materials, which can conveniently modulate the composition and dielectric properties of the ceramics. In this paper, SiBCN ceramic matrix composites with excellent high-temperature wave-transparent performance were prepared through PDC method. Three hyperbranched polyborosilazanes (PBSZs) were prepared by adjusting the type of chlorosilane monomers containing different numbers of methyl groups. The carbon element of pyrolytic ceramics was tuned by adjusting the molecular structure of the precursor and the pyrolysis temperature. The lower the methyl number and pyrolysis temperature, the lower the dielectric constant of the polymer-derived SiBCN ceramics, which is favorable for electromagnetic wave (EMW) transmittance. The average EMW transmittance of SiBCN-C pyrolyzed from hyperbranched PBSZ using trichlorosilane at 1000 ℃ was 90.56% at room temperature. More excitingly, the excellent wave-transparent performance was also maintained in the temperature range of 100-800 ℃. At the test temperature of 800 ℃, SiBCN-C-1000 still had excellent wave-transparent performance with minimum and average EMW transmittance of 76.13% and 88.96%, respectively. This paper provided a new idea for the preparation of high-temperature wave-transparent SiBCN composite ceramics.
研究领域:
材料科学
·
电磁功能材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）