INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2018
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IF 2.606
Zhuang Lu,Limeng Liu,Zhaoping Hou,Biao Zhang,Guihong Geng,Yujin Wang,Feng Ye
TaC-Al 2 O 3 composites were prepared by hot pressing. Influence of Al 2 O 3 content ranging from 10 to 40 vol. % on densification, phase composition, microstructure, mechanical properties and oxidation behavior of the TaC-Al 2 O 3 composites was investigated. With 30 and 40 vol. % Al 2 O 3 addition a closed porosity was achieved. The Al 2 O 3 particles were uniformly distributed among TaC grains retarding grain growth and resulting in refined microstructures with grains below 2 μm in size. The most densified composite with 40 vol. % Al 2 O 3 addition exhibited good mechanical properties with a Vickers’ hardness of 17.8 GPa, a flexural strength of 485 MPa and a fracture toughness of 5.4 MPa·m 1/2 . After holding at 700°C for 3 h in air, the dense 30 and 40 vol. % Al 2 O 3 compositions showed hardly noticeable and mainly surface oxidation, whereas less densified TaC-Al 2 O 3 composites with 10 and 20 vol. % Al 2 O 3 content and with open porosity were disintegrated to powders.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2020
·
IF 4.551
Wei Xu,Jichao Wang,Pan Zhang,Nikom Klomkliang,Somboon Chaemchuen,Francis Verpoort
A facile growth of microporous ZIFs , such a s ZIF-67, ZIF-8 into mesoporous alumina to obtain hierarchical micro/mesoporous ZIFs@Al 2 O 3 is achieved. Several analysis techniques, such as powder-XRD, SEM, ICP, and gas adsorption , etc. are applied to characterize the composite materials. The use of a surfactant is the critical parameter to functionalize and assist the nano-crystal ZIFs growth in meso -Al 2 O 3 . To obtain a high crystal density ZIF-growth in meso-Al 2 O 3 different parameters are tuned such as the surfactant (type and concentration), precursor concentration of ZIFs, and synthesis cycle of the composite material. The synthesis strategy is applicable for any ZIFs to be hybridized on supporting media such as m eso -Al 2 O 3 . Furthermore, the application of ZIF-67@Al 2 O 3 as a catalyst is examined and shows a high performance and recyclability for applications such as the Knoevenagel condensation and CO 2 fixation reaction with epoxides. The highly active sites are distributed on a larger particle support (m eso -Al 2 O 3 ) is found to enhance the catalytic performance. Finally, the main advantage of the composite material is the straightforward handling compared to the use of bulk phases MOFs as a catalyst.
研究领域:
材料科学
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催化化学
·
纳米技术
✓ 已验证
DOI
高影响因子
POLYMER COMPOSITES
·
2024
·Vol. 45
·期 12
·11112-11124
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IF 4.8
Jian Qiao,Yang Lv,Yun Chen,Wei Yang,Chong Zhang,Xin Chen,Chunyu Wong,Qing Liu,Jibao Lu,Tao Zhang,Xiaoliang Zeng,Rong Sun
The relationship between interfacial structure and thermal conductivity in epoxy resin/Al 2 O 3 composite is important but is still elusive. Here, we illuminate this issue by investigating the role of four silane coupling agents in thermal conductivity for epoxy resin/Al 2 O 3 composites. The results show that 3-glycidoxypropyltrimethoxysilane (KH560) is the best silane coupling agent to modify Al 2 O 3 , resulting in the lowest viscosity and the highest thermal conductivity of the epoxy resin/Al 2 O 3 -KH560 composite compared with alternative systems. This is attributed to the strong interfacial interaction between Al 2 O 3 -KH560 and epoxy resin, as confirmed by the Fowkes model and broadband dielectric spectroscopy. The interfacial thermal resistance between the epoxy resin and Al 2 O 3 is also quantitatively measured via a photothermal radiometry technique. The epoxy resin/Al 2 O 3 -KH560 also has the lowest interfacial thermal resistance (1.50 ± 0.02 × 10 −6 m 2 K W −1 ), compared with the other three systems. This study advances the understanding of the relationship between interfacial structure and thermal conductivity in polymer composites. Highlights The relationship between interfacial structure and thermal conductivity in epoxy resin/Al 2 O 3 composite is understood. The interfacial structure is characterized by broadband dielectric spectroscopy. The interfacial thermal resistance is quantitatively measured via a photothermal radiometry technique.
研究领域:
材料科学
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热传导工程
✓ 已验证
产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2022
·
IF 9.221
Qianchun Zhang,Yuxian Zhao,Xuan Shang,Shan Tang,Li Jiang,Yun Wu,Qin Zhou,Shiqin Li
Methallyl alcohol (MA), which is a common volatile organic compound, in vapor form can cause respiratory irritation, headache, nausea, and vomiting. Therefore, the development of a highly selective, excellently sensitive, and efficient sensor for rapidly identifying trace MA is essential. In this study, a La 2 O 3 /α-Al 2 O 3 composite with excellent cataluminescence (CTL) activity in the presence of MA was successfully synthesized. The CTL sensor based on as-prepared La 2 O 3 /α-Al 2 O 3 exhibited high selectivity for MA vapor as well as response and recovery times of 1 and 6 s, respectively. Under the optimal conditions for MA detection, the La 2 O 3 /α-Al 2 O 3 sensor exhibited a linear range of 0.0025–0.50 mg/L (correlation coefficient, R 2 = 0.998) and a low limit of detection of 0.61 μg/L at a signal-to-noise ( S/N ) = 3. The La 2 O 3 /α-Al 2 O 3 sensor was also used to determine the MA content in spiked samples and volatile gases generated from a medicine cabinet. Excellent recoveries in the range of 82.5–107% were obtained, with a corresponding relative standard deviation ( n = 5) in the range of 2.1–4.7%. Furthermore, the CTL sensing mechanism was investigated through density functional theory and high-performance liquid chromatography-ultraviolet analyses.
研究领域:
环境科学
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材料科学
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分析化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Wenwu Zhou,Li Yang,Lang Liu,Zhiping Chen,Anning Zhou,Yating Zhang,Xinfu He,Faxiang Shi,Zegao Zhao
Highly ordered mesoporous TiO 2 -Al 2 O 3 composites with different TiO 2 mass contents (MA-xTi) were successfully synthesized via an improved solvent evaporation-induced self-assembly method and the corresponding NiMo supported hydrodesulfurization (HDS) catalysts were prepared via wetness incipient co-impregnation method. The materials were characterized by means of XRD, ICP-OES, N 2 physical adsorption-desorption, SEM, TEM, Py-FTIR, H 2 -TPR, HRTEM and XPS and the catalytic activities for 4,6-dimethyldibenzothiophene (4,6-DMDBT) HDS over the prepared NiMo/MA-xTi series catalysts were investigated. The results show that the crystal forms, crystal morphologies, pore structures, pore arrangements and acidity properties of the MA-xTi samples varied with the incorporation and increase of TiO 2 species; the interaction between the active metals and the support materials (MSI) can be modulated by the incorporation of TiO 2 species, and TiO 2 incorporation also can promote the formation of the so-called “Type II” NiMoS active phase via changing the morphology of Ni promoted MoS 2 slabs, promoting the sulfidation of both Ni and Mo species and enhancing the proportion of NiMoS phase. The catalytic evaluation results show that the enhancement in the overall HDS activity of the NiMo/MA-xTi series catalysts were mainly contributed by the enhancement in the hydrogenation desulfurization (HYDS) activity. Catalyst NiMo/MA-20Ti exhibited the superior catalytic performance due to its highly ordered mesopore arrangement, proper acidity, moderate MSI, moderate stacking and high proportion of NiMoS phase which leads to more highly active “Type II” active sites.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2021
·
IF 3.871
Bin Han,Shigen Zhu,Weiwei Dong,Yunfeng Bai,Hao Ding,Yilan Luo,Ping Di
In this study, 85-xWC-xTiC-15wt%Al 2 O 3 (x = 0, 5, 10 and 20 wt%) composites were fabricated via hot pressing sintering technology. The influences of TiC additives on the mechanical performance and electrochemical behavior of WC-Al 2 O 3 composite in NaCl solution were investigated. The mean size of WC grain showed a downward trend with the increase of TiC content. The relative density, hardness and fracture toughness of WC-based composites were improved by TiC additives. The maximum values of mechanical performance were obtained when TiC content was 10 wt%. Moreover, the research results indicated that TiC additives significantly increase the corrosion potential and decrease the corrosion current density in NaCl solution. When TiC content increased, the charge-change resistance (R ct ) value presented an uptrend, and then decreased obviously when the TiC content reached 20 wt%. The XPS spectrum and SEM images proved that TiO 2 passivation film was formed on the surface of WA15-10TiC composite. Therefore, it could be concluded that TiO 2 passive film could inhibit further corrosion of the composite.
研究领域:
材料科学
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腐蚀科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Bin Han,Shigen Zhu,Weiwei Dong,Yunfeng Bai,Hao Ding,Yilan Luo,Ping Di
(85-x)WC–15 wt%Al 2 O 3 –xTiC (x = 0, 1.5, 2.5, 5, 10, and 20 wt%) composites were prepared by vacuum hot-press sintering. The influence of TiC addition on the corrosion behaviour of WC–Al 2 O 3 composites in 0.1 M NaOH solution was revealed. The results suggest that all the samples containing added TiC had the TiC phase and (W, Ti) C solid-solution phase, while the base composite had neither phase. With increasing added TiC content, the average grain size of WC decreased, and the relative density first increased and then decreased. Furthermore, the results suggest that the addition of TiC could noticeably increase the free corrosion potential and impedance and reduce the corrosion current density. However, the composite containing 20 wt% added TiC showed the opposite trend. Therefore, it can be concluded that the corrosion performance of the composites in an alkaline medium can be improved by adding an appropriate amount of TiC. The change in corrosion properties was caused by changes in the solid-solution phase, relative density, and TiO 2 oxide film .
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2023
·
IF 3.5
Wenzhuo Xue,Zilong Xiong,Yupeng Chen,Feihu Tan,Hongyu Yu
High frequency performance and the content of glass are the direct factors affecting the performance of LTCC . In order to reduce the content of glass and improve the performance, we conducted a systematic study on the composition regulation of B 2 O 3 -La 2 O 3 -ZnO (BLZ) glass. Glass with low softening point is helpful for LTCC to achieve compact structure. DSC shows that the softening point of BLZ glass can be reduced from 580 ℃ to 537 ℃ by adjusting the composition. XRD analysis indicate that the glass and Al 2 O 3 formed ZnAl 2 O 4 interfacial phases. Combined with the thermal shrinkage curve, it can be proved that the softening of glass and the formation of interfacial phases are the reasons for the shrinkage and densification of LTCC. The lowest coefficient of thermal expansion of 2.878 ppm/℃ was obtained, and the minimum loss of LTCC is 0.00277 at 15 Ghz. These properties are making LTCC more suitable for high-frequency applications.
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
ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Xi Chen,Qiang Li,Meng Zhang,Juanjuan Li,Songcai Cai,Jing Chen,Hongpeng Jia
CH4 production from CO2 hydrogenation provides a clean approach to convert greenhouse gas CO2 into chemical energy, but high energy consumption in this reaction still restrains its further application. Herein, we use a light-driven CO2 methanation process instead of traditional thermocatalysis by an electrical heating mode, with the aim of greatly decreasing the energy consumption. Under UV–vis–IR light irradiation, the photothermal CO2 methanation over highly dispersed Co nanoparticles supported on Al2O3 (Co/Al2O3) achieves impressive CH4 production rates (as high as 6036 μmol g–1 h–1), good CH4 selectivity (97.7%), and catalytic durability. The high light-harvesting property of the catalyst across the entire solar spectrum coupled with its strong adsorption capacity toward H2, CO2, CO, and abundant active sites are proposed to be responsible for the better photothermocatalytic performance of Co/Al2O3. Furthermore, a novel light-promotion effect is also revealed in CO2 methanation, where UV–vis light irradiation induces oxygen vacancies and improves the proclivity toward adsorption of H2, CO2, and CO, finally resulting in a significant enhancement of the photothermocatalytic activity for CH4 production. By concentrating the low-intensity light (120 mW/cm2) via a Fresnel lens, a photothermal CO2 conversion efficiency of more than 50% with a good CH4 selectivity (76%) is achieved on the optimal catalyst under a dynamic reaction system, which indicates the bright prospect of photothermal CO2 methanation.
研究领域:
化学工程
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能源科学
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环境科学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Ruoming Tong,Rui Fu,Zhe Yang,Yuanxing Jiang,Kun Jiang,Xuhui Sun
In this work, CuO-Al 2 O 3 composites were synthesized at higher temperatures to control the leaching of metal ions , which can activate sulfite (S(IV)) to degrade organic contaminants by generating reactive oxygen species (ROSs). The synthesized catalysts were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy , Brunauer-Emmett-Teller, Raman spectroscopy , and Fourier transform infrared spectrophotometry . Sulfachloropyridazine (SCP) was almost completely removed (＞99%) at pH 6.8, and the leaching amount of Cu accounted for 0.027% of the total amount of Cu after the reaction. Notably, singlet oxygen ( 1 O 2 ) was found for the first time in the activated sulfite system, which removed organic pollutants together with sulfate (SO 4 •- ) and hydroxyl (∙OH) radicals. And Al 2 O 3 plays an important role in the catalyst, including anti-sintering, reducing the leaching of copper ions , and promoting the generation of oxygen vacancies. Based on the types of ROSs and X-ray photoelectron spectroscopy results, a possible ROSs generation mechanism was proposed. In addition, the stability of the catalyst and the effect of different factors on the degradation of SCP, including operating parameters and water quality, were further investigated. The intermediates were detected by using gas chromatography-mass spectrometry and a developmental toxicity assessment of the intermediates was defined based on the Toxicity Estimation Software Tool (TEST). Overall, this paper not only provides a new strategy for sulfite activation but also promotes more attention to non-radical processes in activated sulfite systems.
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Juan Xi,Guohua Chen,Fei Liu,Fei Shang,Jiwen Xu,Changrong Zhou,Changlai Yuan
In view of lead-free low-softening CuO–ZnO–B 2 O 3 –Li 2 O glass, novel glass/Al 2 O 3 ceramic composites were prepared by solid-state reaction route for ultra-low temperature co-fired ceramic (ULTCC) applications. The phase evolution and compositions, microstructure and microwave dielectric properties of the composites were studied by XRD , SEM and dielectric property measurement. Four phases including Cu 2 Al 6 B 4 O 17 , Li 2 CuB 4 O 8 , CuB 2 O 4 and Al 2 O 3 coexist in the glass/Al 2 O 3 ceramic composites sintered in the range of 640–660 °C. However, the contents and types of the phases depend on the composition of the composites and firing temperature. The optimum properties with a permittivity ε r = 3.79, a quality factor Q × f = 38557 GHz (at 16.64 GHz) and a temperature coefficient of resonance frequency τ f ≈0 ppm/ o C as well as a heat conductivity λ = 1.46W(mK) −1 can be achieved for the glass/ceramic composite containing 10 wt% Al 2 O 3 sintered at 640 °C. Moreover, the composite can be co-fired compatible with Ag and Al electrodes.The as-prepared glass/Al 2 O 3 ceramic composites are promising candidate for ULTCC application.
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
Advanced Science
·
2023
·Vol. 10
·期 31
·2303815
·
IF 15.1
Junli Ma,Zhenzhen Guo,Xu Han,Heng Lu,Kaixin Guo,Jianguo Xin,Chaoyong Deng,Xianbao Wang
Water evaporation is a ubiquitous and spontaneous phase transition process. The utilization of solar-driven interface water evaporation that simultaneously obtains clean water and power generation can effectively alleviate people's concerns about fresh water and energy shortages. However, it remains a great challenge to efficiently integrate the required functions into the same device to reduce the complexity of the system and alleviate its dependence on solar energy to achieve full-time operation. In this work, a multifunctional device based on reduced graphene oxide (RGO)/Mn 3 O 4 /Al 2 O 3 composite nanomaterials is realized by an asymmetric strategy for effective solar-thermal-electro integration that can induce power generation by water evaporation in the presence/absence of light. Under one sun irradiation, the solar-driven evaporation rate and output voltage are 1.74 kg m −2 h −1 and 0.778 V, respectively. More strikingly, the nine-grid evaporation/power generation array integrated with multiple devices in series has the advantages of small volume, large evaporation area, and high power generation, and can light up light-emitting diodes (LEDs), providing the possibility for large-scale production and application. Based on the high photothermal conversion efficiency and power production capacity of the RGO/Mn 3 O 4 /Al 2 O 3 composite evaporation/generator, it will be a promising energy conversion device for future sustainable energy development and applications.
研究领域:
材料科学
·
能源科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）