Advanced Materials Interfaces
·
2023
·Vol. 10
·期 10
·2201315
·
IF 5.4
Qiangqiang Ma,Chenxu Zhang,Linlin Ren,Xiaoliang Zeng,Jian-Bin Xu,Rong Sun,Yimin Yao
Elastomeric composites are an important class of thermal interface materials as they are shape-adaptive, which can fit uneven interfaces and achieve ideal interfacial heat transfer in electronic cooling. There is often a trade-off between mechanical and thermal performances in highly filled composites. Here, the surface chemistry of Al powders via introducing dodecyltrimethoxysilane (DTS) upon different grafting densities is precisely controlled. The results show that the DTS grafting density of 0.24 molecule nm −2 endows the composites with optimized mechanical properties. The tensile stress, elongation at break, and Young's modulus are enhanced by 180%, 56%, and 94.4% after DTS grafting, respectively. Meanwhile, the composite possesses a high fracture energy of 356.2 J m −2 with an enhanced strain energy density of 37.6 kPa. The DTS grafting on Al also contributes to higher thermal conductivity (4.4 W mK −1 ) and lower contact thermal resistance (0.52 °C cm 2 W −1 ) of the composites and significantly improves the stability of the composites upon high-temperature storage. Guidance is provided here on methods and data references for optimizing the performance of elastomeric composites, which helps to expand their practical application in electronic cooling.
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JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2023
·Vol. 106
·期 2
·616-625
·
IF 2.5
Wang Xuan,Qian Junjie,He Chao,Shui Anze,Du Bin
Al-doped-SiOC ceramics were fabricated via condensation polymerization and then pyrolysis of preceramic precursor in this study. The Al cation induced the formation of mullite, SiO 2 and graphitic carbon. Results showed that the incorporation of Al element enhanced the thermal stability of SiOC ceramics under Ar atmosphere via suppressing carbothermal reduction. This was consistent with the observation from Raman spectra by curve-fitting according to the D-to-G peak intensity ratio. In addition, the thermal stability of the SiAlOC ceramics under air atmosphere was also investigated. The formation of the mullite phase under the air atmosphere indicated that the SiAlOC ceramics possessed better oxidation resistance properties than the pure SiOC ceramics. This work provides a new guide to fabricating metal-modified SiOC ceramics with desired structures. Graphical Abstract
The introducing Al element greatly enhanced the thermal stability of SiOC ceramics via restraining in-situ formation of SiC. The structural evolutions of Al cation-modified-SiOC ceramics both in argon and air atmospheres were investigated systematically.
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Journal of Materials Research and Technology-JMR&T
·
2023
·
IF 6.4
Yang Wang,Qiang Liu,Biao Zhang,Hongxu Wang,Paul J. Hazell,Zhuoqun Han,Jian Li,Bo Li,Ling Li,Futian Liu,Feng Ye
Functionally graded materials (FGMs) are promising protective structures for lightweight armor plates because of their features and designability. However, traditional discretely layered FGMs with macroscopic interfaces can generate unfavorable interlaminar stresses under ballistic attacks, eventually leading to delamination or interlayer tearing. Herein, we constructed new B 4 C/2024Al FGMs without sharp interfaces between layers. The FGM armor systems with varying through-the-thickness distributions were tested against 7.62 mm armor-piercing incendiary projectiles. The effects of compositional gradient exponent on the damage characteristics, stress distribution and energy evolution were numerically and experimentally investigated. The results indicated that the smooth transition within through-the-thickness microstructures effectively avoided the occurrence of interlayer delamination or tearing. The compositional gradient exponent played an essential role in the impact response of the FGM targets. The FGM having a linear composition gradient outperformed other nonlinear types with respect to energy absorption and ballistic properties due to the reduced tensile wave strength and prolonged projectile-target interaction time. Furthermore, the structural optimization problem with the objective of maximizing ballistic efficiency was solved using the conjugate gradient method, and the optimal design of the FGM targets was achieved. The current research provides a promising design guideline for developing and optimizing new advanced lightweight composite armor.
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Molecular Catalysis
·
2022
·
IF 5.089
Rongzhao Li,Chengtao Zhang,Shuo Li,Yupeng Du
Propane dehydrogenation is commonly operated at temperatures exceeding 600 °C due to thermodynamic requirements. However, high temperature accelerates the deactivation of catalysts because of the coke deposition. Therefore, it is quite necessary to develop catalysts with high catalytic activity and improved anti-coking ability. To this end, an Al-doped Cr 2 O 3 catalyst derived from MIL-101(Cr/Al) is prepared in this work. The preparation conditions, including the carbonization temperature of MIL-101 and the proportion of Cr/Al, are optimized via experimental studies. Meanwhile, the adsorption and dehydrogenation behaviors of propane on the catalyst are investigated using Density Functional Theory (DFT) methods. Findings indicate that the optimum carbonization temperature and Cr/Al proportion are 900 °C and 6:4, respectively. Under the reaction condition of P = 0.1 MPa, T = 580 °C and GHSV = 800 h −1 , the propane conversion and propylene selectivity on the Cr 6 /Al 4 catalyst are 19.5% and 92.0%, respectively. The activity stability of the Al-doped Cr 2 O 3 is elongated significantly due to the lower desorption energy of propene and higher energy barrier for the coke formation on the catalyst. In sum, the present work completed via experiments and DFT calculations will lead to a better understanding of the Al-doped Cr 2 O 3 catalyst and guide the rational design of anti-coking catalysts for propane dehydrogenation.
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CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Jiayi Wang,Chunhao Wan,Qi Tang,Jian Xu,Nianxi Xu,Shansheng Yu,Xiaoyi Wang,Hongwei Tian
Due to the harmful influence of electromagnetic waves, electromagnetic absorption materials are being actively pursued. Herein, a one-step hydrothermal method is used to synthesize rGO/Al/CoFe 2 O 4 composites with different amounts of CoFe 2 O 4 , and their electromagnetic properties and infrared emissivity are studied in detail. The results reveal that the rGO/Al/CoFe 2 O 4 composite with a CoFe 2 O 4 content of 0.06 g possesses a minimum reflection loss (RL min ) of −68.03 dB at 15.5 GHz at a thickness of 1.38 mm, while the effective absorption broadband (EAB) and infrared emissivity are found to be 3.3 GHz and 0.63, respectively. Hence, the as-designed rGO/Al/CoFe 2 O 4 composites can be used for both wave absorption and low-infrared emissivity fields, and the proposed strategy is an effective solution for designing bifunctional wave absorption materials.
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Sustainable Energy & Fuels
·
2023
·Vol. 7
·期 4
·1027-1040
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IF 5.6
Ke Gao,Xianglei Liu,Qi Wang,Zhixing Jiang,Cheng Tian,Nan Sun,Yimin Xuan
Solar thermochemical CO2 splitting has emerged as a promising strategy for solar fuel production to alleviate climate change challenges and reduce the energy crisis. However, traditional redox materials still suffer from low CO production, poor cycle stability, high operating temperature, and large temperature swing, leading to low solar-to-fuel efficiency. Herein, Ce- and Al-doped SrMnO3 perovskites are proposed for high-performance solar thermochemical CO2 splitting within moderate temperature swing (1350/1100 °C). Sr0.6Ce0.4Mn0.8Al0.2O3 demonstrates a remarkable CO yield of 799.34 μmol g−1, which is ∼6.67 times as high as that of benchmark CeO2. Fast CO2 splitting kinetics of SCMA20 is demonstrated by the CO peak production rate enhanced by 142% compared with undoped SrMnO3. The proposed Sr0.6Ce0.4Mn0.8Al0.2O3 also exhibits excellent stability with no obvious deactivation or degradation over multiple cycles. The ultrahigh CO yield can be attributed to lower oxygen vacancy formation (3.65 eV) and migration energy (2.14 eV) as confirmed by DFT calculations, and the transformation of the first-order reaction (F1) to the second-order reaction (F2) compared to SrMnO3. This work provides a new path for high-performance solar thermochemical CO2 splitting with high CO production, fast reaction kinetics, good cycling stability, moderate temperature swing, and high solar absorptance.
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International Journal of Environmental Research and Public Health
·
2022
·Vol. 20
·期 1
·671
·
IF 4.614
Yameng Ma,Jia Zhu,Jianghua Yu,Yicheng Fu,Chao Gong,Xiao Huang
Phosphorus widely existing in rainfall and wastewater impacts the water environment. In this study, sludge, cement block, and coal fly ash were employed as ceramsite material to synthesize Al-doped waste ceramsite (Al-ceramsite) for removing phosphate (PO43−-P) from aqueous solutions. Batch static adsorption–desorption experiments were designed to investigate the effect of various parameters such as Al-ceramsite dosage, PO43−-P concentration, temperature, initial pH, coexisting ions, and desorbents on the removal of PO43−-P. Also, the fate of PO43−-P removal efficiency in actual rainwater was studied through dynamic adsorption column experiments using Al-ceramsite. Results showed that Al-ceramsite could remove PO43−-P efficiently under the optimum parameters as follows: Al-ceramsite dosage of 40 g/L, initial PO43−-P concentration of 10 mg/L, temperature of 25 °C, and pH of 5. Besides that, the Al-ceramsite could completely remove PO43−-P in actual rainwater, and the effluent PO43−-P concentration was lower than the environmental quality standards for surface water Class Ⅰ (0.02 mg/L). The adsorption characteristics of Al-ceramsite on PO43−-P by X-ray photoelectron spectroscopy (XPS) were further explained. As a result, ligand exchange and complexation were confirmed as the main PO43−-P removal mechanism of Al-ceramsite. Thus, Al-ceramsite was prepared from industrial waste and has shown excellent potential for phosphorus removal in practical applications.Keywords:phosphate;ceramsite;adsorption;desorption;column experiment
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Yaofeng Mao,Jie Chen,Jian Wang,Wei Cao,Jun Wang,Fude Nie
Fluorinated reactive materials as new energetic materials are widely studied because of their high combustion heat and the ability to release large amounts of gaseous products. In order to further improve combustion reaction and the energy release efficiency, structural processing strategy is usually adopted to construct unique microstructures for fluorinated reactive materials. In this work, it is found that fluorinated graphene (FG) and nano-aluminum (nAl) can be rapidly assembled by the intercalation-like method to form multilayer nanostructured energetic materials with particle mosaic. Based on this, the energy output performance of these multilayer nanostructured energetic materials can be effectively regulated by changing the ratio of FG to nAl. The shortest laser ignition delay time (8 ms) and the longest burning time (56 ms) can be achieved for the multilayer nanostructured energetic material with proper FG/Al ratio, while the burning rate of the sample spline can reach 14.83 cm/s. In addition, the reaction process of multilayer nanostructured FG/Al energetic materials depends upon oxygen content that participates in the reaction in different atmospheres, leading to the different pressure output performance. This study provides a promising strategy for the further application of fluorinated reactive materials in the field of energetic materials.
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POLYMER TESTING
·
2023
·
IF 5.1
Xiang Lv,Jiaxing Xu,Ruixuan Xu,Wuxi Xie,Qazi Wasiullah,Qi-Long Yan
In this paper, the mechanical properties of a typical four-component composite solid propellants with various designed Al/oxidizer interfaces have been studied. The Al/oxidizer interfacial control is mainly realized by using the core-shell composites AP@Al and Al@RDX with different particle sizes, where Al powder was coated with a thin layer of polydopamine (PDA) as the binding sites, so that the oxidizers could crystalize on it during a rapid spray granulation process. The stress-strain curves of the above propellants at different temperatures and different tensile rates have been obtained. The dependence of the loss factor on temperature was studied by using a dynamic thermomechanical analysis (DMA). It has been shown that the fracture elongation of the interfacial modified propellants can reach 51.81% at room temperature, which is 127.3% higher than that of the blank formulation under the same formulation. Moreover, the temperature and strain rate sensitivity of interfacial controlled HTPB propellants is much less than that of traditional ones. The microstructure of these propellants at the crack sites was investigated by scanning electron microscopy (SEM) supported with micro-area in-situ tensile CT scanning technology, to clarify their damage and failure mechanisms.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Yuxuan Zhou,Yueting Wang,Zehua Zhang,Fuwei Li,Jian Cheng,Yinghua Ye,Jianbing Xu,Ruiqi Shen
The application and optimization of nano-composite energetic materials in the extreme and particular environment have become a subject of wide concern. Additionally, the design and selection of metastable intermixed composites (MICs) films in low pressure environment is the key problem to explore its future application. Here, 90 wt% high loading Al/CuO nanothermite films were prepared by a simple 3D direct writing approach. Four films with different thicknesses (66, 128, 152, 182 μm) were designed and their combustion properties were tested respectively. The low pressure combustion results show that the self-sustained burning rate of the film (thicker than 66 μm) can be adjusted and controlled in various air pressure environments (101–60 kPa). The self-sustained burning rate of film is affected by both thickness (66–182 μm) and air pressure (101–60 kPa). The lower the air pressure, the lower the burning rate. The greater the thickness, the higher the burning rate. The 66 μm film self-sustainedly burns at atmospheric pressure and extinguishes when the pressure was significantly reduced. The self-sustained combustion rates of the 128 and 152 μm film decreases with decreasing pressure until the pressure drops to 75 and 60 kPa respectively. The 182 μm film keeps self-sustained combustion in a manner of deflagration which is almost unaffected by air pressure, even when the pressure drops to 10 kPa. Simultaneously, it is found that the ignition temperature of the film is almost not affected by pressure. In addition, it is verified that the film has performances of excellent hydrophobic and combustion through air–water interface. These can cope with complex environmental humidity.
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CHEMOSPHERE
·
2023
·
IF 8.8
Hao Li,Canyuan Lin,Ruhui Ma,Yuancai Chen
In this study, the selective adsorption of aromatic compounds on mesoporous MIL-53(Al) was investigated, and followed the order: Biphenyl (Biph) > Triclosan (TCS) > Bisphenol A (BPA) > Pyrogallol (Pyro) > Catechol (Cate) > Phenol (Phen), and exhibited high selectivity toward TCS in binary compounds. In addition to hydrophobicity and hydrogen bonding, π–π interaction/stacking predominated, and more evidently with double benzene rings. TCS-containing halogens could increase π interaction on the benzene rings via forming Cl–π stacking with MIL-53(Al). Moreover, site energy distribution confirmed that complementary adsorption mainly occurred in the Phen/TCS system, as evidenced by Δ Q pri (the decreased solid-phase TCS concentration of the primary adsorbate) < Q sec (the solid-phase concentrations of the competitor (Phen)) . In contrast , competitive sorption occurred in the BPA/TCS and Biph/TCS systems within 30 min due to Δ Q pri = Q sec , followed by substitution adsorption in the BPA/TCS system, but not for the Biph/TCS system, likely attributed to the magnitude of energy gaps (E g ) and bond energy of TCS (1.80 eV, 362 kJ/mol) fallen between BPA (1.74 eV, 332 kJ/mol) and Biph (1.99 eV, 518 kJ/mol) according to the density-functional theory of Gaussian models. Biph with a more stable electronic homeostasis than TCS lead to the occurrence of substitution adsorption in the TCS/BPA system, but not in the TCS/Biph system. This study provides insight into the mechanisms of different aromatic compounds on MIL-53(Al).
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Ling Pan,Ling He,Zibo Niu,Peng Xiao,Wei Zhou,Yang Li
In this work, Yb 4 Hf 3 O 12 ceramic, a typical rare-earth hafnate, was exposed to water vapor with Al(OH) 3 impurities at 1400 ℃, and microstructural evolution and corrosion mechanisms were investigated. The long-term corrosion can be divided into initial hydration and gasification of Hf 4+ and steady-state corrosion after the formation of Al 5 Yb 3 O 12 . In the initial stage, Hf 4+ and the surrounding O 2- tend to be hydrated and then volatilized in the form of Hf(OH) 4 , causing a metastable state of Yb 4 Hf 3 O 12 on the surface. Besides, the preferential corrosion of small grains, grain boundary, and specific crystal plane on the surface and sintered and densified grains result in varied corrosion behavior from the early linear law to the later parabolic law. In the steady-state corrosion stage, due to the consumption of Hf 4+ , more vacancies promote bonding and diffusion of Al 3+ to form corrosion product (Al 5 Yb 3 O 12 ), and during this stage, regrowth and shedding of the corrosion layer reach a dynamic balance.
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