CERAMICS INTERNATIONAL
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2022
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IF 5.532
Ze Zhang,Cunqian Fang,Yuanqi Weng,Xiao Luo,Qizhong Huang,Huiping Hu
Graphene was introduced into C/C–SiC composites via pressureless impregnation to enhance the mechanical and thermal properties of the composites. The effects of various graphene contents on the mechanical and ablative performances of C/C–SiC composites were investigated. The results showed that the ultimate bending stress and compressive stress of the C/C–SiC composites increased by 28.98% and 23.64%, respectively, after adding 7.25% graphene. Moreover, the ablation rates of the composites were vastly decreased after adding a slight graphene content (2.13%). However, the ablation rates increased with increasing of graphene content, indicating that the benefit of introducing graphene on the ablation property decreased, which was mainly ascribed to the relative reduction in the SiC content. As a result, introducing slight graphene into C/C–SiC composites had the greatest benefit on the anti-ablation performance.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
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IF 15.1
Qiuyan Ding,Hengyu Shen,Zongliang Kou,Hong Li,Xiaolei Fan,Xiaoxia Ou,Yilai Jiao,Xin Gao
Rational design of catalytic packing is crucial in developing reactive distillation (RD) processes as efficient in-situ coupling of reaction and separation is required. Structured catalytic packings are advantageous than the conventional packings (e.g., inert packing + catalyst ‘tea bags’), due to the integration of the catalysis and separation function in one unit, mitigating mass/heat transfer limits. Herein, we present one of the latest developments in the field of structured catalytic packings, which was applied to a pilot-scale RD process of ethyl lactate (EL) synthesis via acid-catalyzed esterification and showed the advantages. The tungstophosphoric acid and hierarchical Y zeolite were uniformly decorated on corrugated silicon carbide (SiC) foam sheets via new preparation method (of ultrasound-assisted impregnation and microwave-assisted drying). The activity of the resulting materials was first assessed in a batch reactor, then the best candidate was employed by the pilot process. Findings from the pilot-scale RD experiments show that the developed structured SiC foam catalytic packing (SSFCP) exhibited an excellent performance (with the normalized conversion of 0.155 mol/g catalyst ), outperforming the conventional seepage catalytic packing internal (0.002 mol/g catalyst ). The influence of various variables (including molar feed ratio, feed position and reflux ratio) on the process performance of the pilot RD rig was also investigated and optimized, achieving a lactic acid conversion of 46.9 % and EL purity of 44.9 % (bottom). The good performance was attributed to the improved mass transfer thanks to SiC foam corrugated sheet (which encourage the vortex formation), thereby enabling more efficient coupling with the reaction. The SSFCP demonstrated reasonable stability, making it a promising candidate for relevant practical RD applications.
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高影响因子
Crystals
·
2023
·Vol. 14
·期 1
·14
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IF 2.7
Yufei Zu,Zi Wang,Hongliang Tian,Fan Wu,Lianshen Fu,Jixiang Dai,Jianjun Sha
High-entropy diboride-based (MeB2-based) ceramics are promising high-temperature structural materials because of their excellent mechanical properties, high-temperature stability, and oxidation resistance. In order to achieve low-temperature sintering of the high-entropy ceramics, a novel preparation method of high-entropy (Ti,Zr,Nb,Mo,W)B2-SiC ceramics based on reactive sintering of pre-alloyed solid-solution metals and nonmetals of Si, C, B4C was conducted in the current work. Mechanical alloying behavior of the mixed metal powders, as well as the phase composition, microstructure, mechanical properties, and oxidation behavior of the as-sintered MeB2-SiC ceramic were investigated. The XRD, SEM, and EPMA results indicated that the primary MeB2solid-solution and SiC phases could be successfully formed during reactive sintering at a relatively low temperature of 1650 °C. The as-sintered MeB2-SiC ceramics had a high relative density of 97.8% and high mechanical properties (hardness of 19.74 ± 0.8 GPa, flexure strength of 533 ± 38 MPa, and fracture toughness of 6.01 ± 0.77 MPa·m1/2). Combining the oxidation behavior and microstructure evolution of the oxidation layer, a continuous and relatively dense MeOx-SiO2oxidation layer was gradually formed and covered on the external surface, leading to decelerating oxidation behavior after an oxidation exposure time of 10 min.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
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IF 5.7
Binwei Huang,Pingzhan Si,Quanxing Ren,Zhuang Qian,Ziqiang Yin,Zhengren Huang,Qing Huang,Yinsheng Li
SiC ceramic was fabricated by spark plasma sintering of β-SiC powder and Y 2 O 3 -MgO additives in argon. The effects of β→α phase transformation of SiC on microstructure and thermal conductivity of densified bulks were systematically investigated, in comparison to the counterparts using α-SiC as starting powder. The β→α phase transformation led to a “unimodal to bimodal” transition in grain size distribution. After sintering at 1850 o C, the incomplete β→α phase transformation induced the appearance of β/α heterophase boundary with strong effect of phonon-scattering. After sintering at 2050 o C, the completion of β→α phase transformation resulted in enlarged grains and disappearance of β/α heterophase boundary in SiC ceramic. The lattice oxygen content was decreased primarily by enhanced grain growth and oxygen picking-up of sintering additives, and possibly some contribution from β→α phase transformation. The optimized microstructure enabled SiC ceramic to obtain a remarkable increase in thermal conductivity from 126 to 204 W/mK after the replacement of α-SiC by β-SiC as starting powder and the accomplishment of β→α phase transformation.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Zhengliang Liu,Wei Zhang,Huanpeng Bu,Ken Chen,Yan Jiang,Huijun Liu,Chaoliu Zeng
A novel SiC–Si coating with a high amount of net-like distributed Si was fabricated on the graphite substrate by liquid silicon infiltration (LSI) method to improve the oxidation-resistant performance. The mass gain of this LSI coating after 300 h oxidation at 1873 K was only 3.018%, suggesting an excellent static antioxidant property at 1873 K. The detailed oxidation mechanism of this LSI coating was explored in this work. It was found that the high amount of Si with the net-like distribution in this LSI coating promoted the passivation growth of SiO 2 glass layer and prevented the SiO 2 glass from crystallizing into cristobalite. In addition, the Si in this coating retarded the active oxidation and enhanced the coating stability. In contrast, the infiltration (VSI) SiC–Si coating presented an apparent mass loss, and the pack cementation (PC) SiC coating showed the catastrophic failure. The oxidation mechanisms of these two coatings were also discussed against the backdrop of the LSI coating with high antioxidant performance.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Sheng-Jin He,Ling-Feng Su,Chuang-Tian Zhan,Xiu-Bin Chen,Wei-Ming Guo,Shi-Kuan Sun,Li-Xiang Wu,Jia-Xiang Xue,Hua-Tay Lin
Low-temperature joining of SiC ceramics using raw CaO-Al 2 O 3 -MgO-SiO 2 mixed powders (CAMS-P) and CaO-Al 2 O 3 -MgO-SiO 2 glass (CAMS-G) as additives for the liquid-phase sintering of SiC nanopowders (NITE phase) in combination with surface oxidation was studied. Using CAMS-P as an additive for SiC joining required 1650 °C and produced a lower shear strength of 77.2 ± 3.5 MPa, compared to untreated SiC (108.2 ± 15.8 MPa). Using CAMS-G as an additive, the compactness of SiC joints obtained at 1550 °C was higher than that of NITE joints obtained at 1650 °C with CAMS-P as an additive. Nonetheless, the low joining temperature resulted in gaps and delaminations at the interface, and the joints strength was only 48.3 ± 5.6 MPa. Incorporating CAMS-G as an additive and surface oxidation achieved reliable NITE phase joining at 1550 °C, with no observed gaps or delaminations at the interface. The resulting joints strength was as high as 100.0 ± 0.8 MPa. The joining mechanism was discussed and compared, involving microstructural analysis .
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高影响因子
COMPOSITES PART B-ENGINEERING
·
2019
·
IF 6.864
Tadele Daniel Mekuria,Chunhong Zhang,Diaa Eldin Fouad
SiC@SiO 2 core-shell nanostructured particles were successfully prepared via simple thermal treatment. The structure of the surfaces of pristine SiC and SiC@SiO 2 core-shell nanostructured particles was investigated by X-ray diffraction spectroscopy (XRD). The formation of SiO 2 shell on the SiC core was further evaluated by FTIR , SEM , XPS and TEM techniques. The nanostructured particles prepared were amino-modified by APTMS and incorporated in polyimide (PI) matrix to prepare highly flexible composite films . The mechanical, thermal, UV-shielding and water proof properties of the composites were investigated. The TGA results displayed that T 5 (5% weight loss temperature) and T 10 (10% weight loss temperature) were meaningfully enhanced up to 56.0 °C and 53.4 °C, respectively upon adding various amounts of modified SiC@SiO 2 nanoparticles into the PI matrix. DSC results revealed that the glass transition temperature ( T g ) was considerably enhanced up to 45.50 °C, up on the incorporation of different dosages of SiC@SiO 2 –NH 2 nanoparticles in the matrix. The tensile results shown that introduction of the nanoparticles into the PI medium exhibited highly significant improvement in the tensile strength and the Young's modulus over 77.1% and 96.6% respectively as compared to the neat PI. The incorporation of SiC@SiO 2 –NH 2 nanostructured particles in the matrix highly improved the hydrophobicity of the composites up to 62.55% as compared to the neat PI. The UV-shielding properties were also enhanced when functionalized SiC@SiO 2 –NH 2 was added to the PI matrix. The dispersion of SiC@SiO 2 in the PI matrix was investigated by Scanning electron microscope (SEM).
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OPTICAL MATERIALS
·
2024
·
IF 3.8
Mengyao Xue,Jingwei Han,Xing Dai,Yucai Ge,Yunhua Zhang,Zibin Hai
Cu 2 O–SiC/g-C 3 N 4 composite photocatalysts with excellent photocatalytic performance under visible light were synthesized for the first time via a facile approach combining calcination with hydrothermal reaction. Comprehensive characterization of the synthesized samples encompassing composition, morphology, structure and photoelectric properties was conducted utilizing techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and electrochemical impedance spectroscopy (EIS). Results unequivocally demonstrate successful preparation of the ternary composite through Cu 2 O loading onto SiC/g-C 3 N 4 , evincing markedly elevated activity compared to individual counterparts and binary composites. Notably, in the presence of the prepared Cu 2 O–SiC/g-C 3 N 4 , the degradation rate of methyl orange reached 93.70 % under illumination with a visible LED light rated at 5 W. The notable enhancement in photocatalytic performance of the ternary composites is primarily ascribed to the synergistic effects stemming from the formation of p-n junctions between Cu 2 O and g-C 3 N 4 , alongside the Z-scheme configuration established between Cu 2 O and SiC. Free radical quenching experiments corroborated •O 2 − and h + as the principal redox species mediating the visible light quenching process. This study not only presents a feasible strategy for the fabrication of Cu 2 O-based ternary composites with significantly augmented photocatalytic performance but also delineates a novel avenue for the design and construction of composite photocatalysts facilitating enhanced charge-carrier generation and separation concomitantly.
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COMPOSITES SCIENCE AND TECHNOLOGY
·
2024
·
IF 8.3
Shiyi Mao,Zijun Pan,Yuhan Ye,Pu Han,Ju Tang,Cheng Pan
The micro-SiC/Epoxy composite coating has huge potential for application in the insulator of high voltage direct current (HVDC) gas insulated switchgear (GIS) since it can effectively suppress charge accumulation at gas–solid interface and adaptively regulate resistive electric field distribution. However, achieving stable and fruitful properties often requires high filler concentrations, which can compromise processability and long-term stability. Thus, a new method is proposed for preparing SiC/Epoxy composite coatings based on in-situ electric-field-induced assist (EFIA). The alignment process of SiC induced by the in-situ electric field, the effects of in-situ field on the physical and chemical properties of cured composites were studied. Even at concentrations far below the percolation threshold, the alignment of SiC particles along the in-situ electric field direction can induce significant non-linear conductive properties along that specific direction in the composite. Furthermore, the EFIA-coating leads to a 59.43% reduction in surface charge accumulation, more than a 50% decrease in charge dissipation time, and a 17.3% increase in surface flashover voltage. The coating discussed in this paper will be helpful in insulation design of DC components.
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Additive Manufacturing
·
2025
·
IF 11.1
Changshun Wang,Qingchun Yang,Huaying You,Yumeng Hu,Chunze Yan,Annan Chen,Shixiang Zhou,Guizhou Liu,Siqi Wu,Yusheng Shi
Silicon carbide (SiC) ceramic-based composites have attracted significant attention for electromagnetic (EM) absorption under extreme environments. However, achieving the balance between impedance matching and attenuation capacity remains an urgent challenge. Inspired by the unique physiological impedance matching and light signal processing characteristics of the compound eye, a synergistic mechanism of macro impedance matching and micro attenuation has been applied to the fabrication of SiC metamaterial absorbers. The excellent impedance matching characteristic was achieved by optimizing the size parameters of frustum pyramid structures. Additionally, the strong intrinsic attenuation capacity was achieved by introducing 3D cross-linked structures constructed by micro/nano SiC fibers. Herein, the compound-eye inspired SiC metamaterial absorber was successfully generated using laser powder bed fusion (LPBF) with an optimized effective absorbing bandwidth (EAB) of 36.06 GHz (3.94−40 GHz) with a printed thickness of 12 mm. The wide-angle absorption was also realized within 0−60° and 0−70° under transverse electric (TE) and transverse magnetic (TM) polarization modes. The compound-eye inspired 3D macro/micro structure integrated strategy provides an efficient approach for the design and fabrication of broadband SiC metamaterial absorbers.
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CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Ruiji Zhang,Fangwei Guo,Wenchen Zhang,Fei Pan,Xing Zhang
Ceramics containing profiled fiber-like additives (nanotubes, whiskers, etc.) show high mechanical properties. However, the toughening mechanism is debated due to its complex multi-scale microstructure. In this work, ZrB 2 (Z)-20 vol%SiC(S) spiral fibers (ZS sf ) were prepared by liquid rope effect and non-solvent induced phase separation, while quantitative relation of mechanical properties and structure were investigated by using SEVNB with femtosecond lasers and in-situ 3D-XRM simulation. The ZrB 2 -SiC composites with hierarchy ZS sf exhibited a ∼60 % increase in fracture toughness (5.45 MPa m 1/2 ) compared with blank composites, while the toughening efficiency of the hierarchy ZS sf increased over 2 times compared to the 1D and 2D toughening additives. The ZS sf with a thin graphite-like layer and spiral structure with hierarchy pores provided a torsional release effect that changed brittle fracture to the pseudoplastic fracture, where topological interlocking of 3D crimped structure hindered rapid cracking propagation. Additionally, the enhanced toughness was attributed to the uniform reconstruction of the stress field induced by hierarchical inner pores. The preserved 3D topological interlocking and uniform stress reconstruction lead to the highly stable fracture toughness of the ZS sf composites up to 1500 °C.
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ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Chuyang Liu,Taian He,Congcong Hu,Qi Qian,Yilin Hao,Lu Xu,Hengyi Lu,Guangbin Ji
In contemporary times, radar and infrared-compatible stealth materials have emerged as a pivotal domain of research globally, aimed at augmenting the survivability of military assets. However, current candidates generally exhibit subpar compatibility performance in elevated temperature environments due to the imbalanced interplay between the two spectral bands. In this work, a meticulously designed sandwich-structure SiO 2 /C@SiC/SiO 2 composite is proposed to cope with the challenge. The middle layer of C@SiC composites possesses excellent microwave absorption performance even at high temperatures. The outer layers of SiO 2 aerogels serve not only to inhibit the infrared radiation intensity, but also reinforce the microwave absorption capacity by optimizing the impedance matching and reducing the heat transferred to the middle layer. Based on the numerical simulation outcomes, the thickness of each layer has been optimized to attain a harmonious balance between microwave absorption and infrared radiation properties. Ultimately, the sandwich structured SiO 2 /C@SiC/SiO 2 composites demonstrate low RL (reflection loss) values (←5 dB) across nearly the entire X band (8–12 GHz), alongside minimal surface temperatures hovering ≈44 °C at an ambient temperature of 200 °C. The comprehensive investigation into impact patterns and underlying mechanisms offers invaluable insights to develop radar and infrared-compatible stealth materials for high-temperature applications, which can be applied as stealth coatings on the skin of high Mach number aircraft.
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