CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Jiaxian Fan,Hongna Fan,Zhuo Song,Yajie Guo,Minmin Li,Xin Li,Changjian Qi,Xiqing Xu
Crucible is a key vessel in superalloy smelting, and high-performance crucible is quite important to the development of superalloy. Pointed at the easy cracking and poor thermal-shock stability of Al 2 O 3 crucibles for superalloy smelting, particle gradation was managed in slip casting of Al 2 O 3 crucibles. The ceramic slurry in good dispersion was prepared by optimizing particle gradation, with solid content of 86 wt% and viscosity of lower than 0.5 Pa s. For the crucible with optimized particle gradation, the density was 2.37 g/cm 3 , the linear shrinkage was less than 2%, the porosity was 18.72%, the bending strength was close to 22 MPa and the thermal expansivity was 2.77 × 10 −6 /°C. Strength retention rate was raised to evaluate the thermal shock stability of crucibles, which was up to 73.5% after five-time thermal shock, well meeting the requirements of crucibles for superalloy smelting, and the superior thermal-shock stability was attributed to the uniform network microstructure and low thermal expansivity. The optimal particle gradation in experiments was explained in terms of Dinger-Funk model. This work provides a reference for preparing high-performance Al 2 O 3 crucibles for superalloy smelting with low thermal expansivity as well as excellent thermal-shock stability.
研究领域:
材料科学
·
陶瓷工程
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产品关联
DOI
高影响因子
ADVANCED ENGINEERING MATERIALS
·
2021
·Vol. 23
·期 6
·2001490
·
IF 3.862
Xu Guo,Xiaohong Chen,Ping Liu,Honglei Zhou,Shaoli Fu,Wei Li,Xinkuan Liu,Fengcang Ma,Zhengpeng Wu
CNTs/Cu-Al 2 O 3 composites are successfully prepared by internal oxidation, chemical vapor deposition and spark plasma sintering (SPS) method. The influence of Al content (0.12 and 0.6 wt%) on the morphology of grown carbon nanotubes and the mechanical properties of composites are systematically studied. The results show that under the same growth process, more carbon nanotubes are obtained on the surface of the powders with 0.6 wt% Al content. The CNTs/Cu-Al 2 O 3 composites with 0.12 wt% Al content displays higher mechanical properties, the tensile strength is 280 MPa, and the micro-hardness is 123.3 HV, which is increased by 40.7 and 78.2% in contrast with that of pure copper, respectively. Moreover, the electrical conductivity of CNTs/Cu-Al 2 O 3 (Al content is 0.12 wt%) composites is still at the high level of 83.2% IACS. This work uses chemical vapor deposition to improve the dispersion and interfacial bonding of CNTs in the matrix and increase the properties of the composites, which provides a new idea for the preparation of high strength metal matrix composites.
研究领域:
材料科学
·
力学
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产品关联
DOI
高影响因子
JOM
·
2025
·
IF 2.3
Wang Ya-Long,Yang Xiao-Hui,Zhang Guo-Hua
A simple and effective method is proposed for producing polycrystalline La 1- x Ce x B 6 (LaB 6 , La 0.75 Ce 0.25 B 6 , La 0.5 Ce 0.5 B 6 , La 0.25 Ce 0.75 B 6 , and CeB 6 )-Al 2 O 3 ceramics. La 1- x Ce x B 6 solid-solution powders were first prepared by the reaction between lanthanum oxides, cerium oxides, boron carbide, and aluminum powders at 1573 K, during which a trace amount of Al 2 O 3 (1–3 wt.%) was inevitably introduced. Subsequently, highly dense (> 98.5%) La 1- x Ce x B 6 -Al 2 O 3 ceramics were produced using spark plasma sintering (SPS) technology at 1850°C, and the results revealed that the existence of Al 2 O 3 can enhance the mechanical properties of La 1- x Ce x B 6 by pinning the grain boundaries and refining the grains. Among the samples, the La 0.5 Ce 0.5 B 6 -Al 2 O 3 composition exhibited the most excellent mechanical properties, which were 22.8 GPa, 4.14 MPa m 1/2 , and 271 MPa for the Vickers hardness, fracture toughness, and flexural strength, respectively. Moreover, compared to the polycrystalline LaB 6 and CeB 6 bulks, the work functions of La 1- x Ce x B 6 bulks were lower, and the presence of Al 2 O 3 had a slight influence on the work function of La 1- x Ce x B 6 .
研究领域:
材料科学
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陶瓷工程
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Xianggang Liu,Hui Chen,Yuxin Zhao,Jingjie Zhang,Xianglong Meng,Guangchun Xiao,Zhaoqiang Chen,Mingdong Yi,Wenyu Liu,Chonghai Xu
Al 2 O 3 /CaF 2 self-lubricating ceramic materials were prepared using a low-toxicity methylacrylamide gelcasting system. The rheological properties of the Al 2 O 3 slurry were analyzed to study the effects of dispersant content, solid loading, and pH on its flowability. Optimal results were achieved with a dispersant content of 0.5 wt%, a solid loading of 54 vol%, and a pH of 9. The relative density of the resulting green body was 56 %, with a strength of 18.2 MPa. After sintering for 2 h in a vacuum furnace at 1650 °C, the material exhibited a hardness exceeding 750 HV and a bending strength above 300 MPa when the CaF 2 content was less than 10 vol%. Additionally, the tribological properties of Al 2 O 3 /CaF 2 under various conditions were investigated, revealing optimal performance at a CaF 2 content of 10 vol%. The average friction coefficient and wear rate were 0.245 and 2.96 × 10 −5 mm 3 /N⋅m, respectively, representing reductions of 48 % and 54 % compared to pure Al 2 O 3 materials. These findings demonstrate that gelcasting is an effective method for preparing self-lubricating ceramic materials, offering a new approach for fabricating complex-shaped self-lubricating ceramic components.
研究领域:
材料科学
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陶瓷工程
·
摩擦学
✓ 已验证
产品关联
DOI
高影响因子
Desalination and Water Treatment
·
2024
·
IF 1
Lihuan Mo,Peiqi Lyu,Zhen Yang,Jie Gong,Kai Liu,Jun Li
Bagasse pulp wastewater has restricted and disturbed the bagasse pulp industry all the time. In this paper, photocatalytic oxidation technology (O 3 +UV+TiO 2 ) was applied to bagasse pulp wastewater treatment. TiO 2 was prepared into a composite photocatalyst (La-TiO 2 /Al 2 O 3 ) to improve the treatment effect. p-Chlorophenol was chosen as a target compound to evaluate the catalytic activity and study the preparation process of La-TiO 2 /Al 2 O 3 . La-TiO 2 /Al 2 O 3 was finally used in the treatment of real bagasse pulp wastewater with photocatalytic oxidation technology. Under an optimum experiment conditions, chemical oxygen demand (COD) and total organic carbon removal rate of bagasse pulp wastewater reached 80.2% and 77.1%, respectively, and AOX dropped to 2.9 mg/L. Most organic pollutants in the wastewater had been removed. Additionally, in the reusability study, COD removal was maintained at 70.5% at 7th reuse. These findings of present study revealed that La-TiO 2 /Al 2 O 3 held great potential in the practical photocatalytic degradation application of industrial organic wastewater.
研究领域:
环境科学
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化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
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2019
·Vol. 30
·期 2
·359-370
·
IF 1.335
Zheng Zhi,Lei Tong,Wang Jun,Wei Yi,Liu Xuejun,Yu Fengwen,Ji Jianbing
In this paper, we report the catalytic cracking of soybean oil for biofuel over γ-Al2O3/CaO composite catalysts. The influence of catalysts, cracking temperature and weight hourly space velocity (WHSV) on the products distribution were investigated. The maximum yield (70.0 wt.%) of biofuel with low acid value (6.7 mg KOH g-1) and oxygen content (5.6%), as well as high calorific value (44.2 MJ kg-1) was achieved over 35 wt.% γ-Al2O3/CaO at 480 ºC and 3.72 h-1. The paper focused on the variation of biofuel composition and cracking pathway caused by γ-Al2O3/CaO composite catalysts via gas chromatography-mass spectrometry (GC-MS) and thermogravimetric (TG) analysis. Calcium oxide would react with fatty acid to yield calcium carboxylates at 300-350 ºC, which were subsequently decomposed into hydrocarbons (57.9 wt.%) and ketones (22.6 wt.%) at 415-510 ºC. As for 35 wt.% γ-Al2O3/CaO, the addition of γ-Al2O3 was beneficial to generate alkenes (38.2 wt.%), arenes (10.6 wt.%) and alcohols (12.3 wt.%) with ketones decreasing (16.5 wt.%) via γ-hydrogen transfer reaction and disproportination.
研究领域:
化学工程
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可再生能源
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Zhoufeng Bian,Wenqi Zhong,Yang Yu,Zhigang Wang,Bo Jiang,Sibudjing Kawi
Catalysts of Ni supported on home-made mesoporous alumina (Ni/M-Al 2 O 3 ) were prepared via facile incipient impregnation method and calcined under different temperature (500–800 °C). Compared with catalysts of Ni supported on commercial alumina, they showed much higher conversion and lower carbon deposition in methane dry reforming (DRM). Among the catalysts, Ni/M-Al 2 O 3 -700 exhibited the highest DRM activity, with 77.6% CH 4 conversion and 85.4% CO 2 conversion at 700 °C. TPR revealed that almost all the Ni was in the form of NiAl 2 O 4 spinel after calcination at 700 °C. Due to the strong metal-support interaction of NiAl 2 O 4 structure, the Ni crystal size of Ni/M-Al 2 O 3 -700 after reduction was around 5 nm. TGA and TEM results showed its carbon deposition after 20 h DRM test was only 3.8% and mainly in the form of amorphous carbon . This work indicates that the formation of NiAl 2 O 4 spinel is beneficial to activity and stability towards DRM reaction and controlling calcination temperature is crucial.
研究领域:
催化化学
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材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHARACTERIZATION
·
2020
·
IF 3.562
Yongxiang Zheng,Chengji Deng,Jun Ding,Hongxi Zhu,Chao Yu
An innovative approach was developed for the fabrication of AlN-Al 2 O 3 porous ceramic by heat-treating Al 4 O 4 C porous ceramic under a flowing nitrogen atmosphere. The effects of sintering temperature on phase and microstructural evolution changes were investigated. The results indicated that phase evolution of the nitridation of Al 4 O 4 C porous ceramics was significantly different from dense Al 4 O 4 C ceramics. AlN-Al 2 O 3 porous ceramic produced using this new method had a homogeneous local chemical composition with the two phases tightly combined in the composite material. Possible reaction mechanisms for the fabrication of AlN-Al 2 O 3 porous ceramic are discussed by considering reactions at the initial and later stages during the nitridation process.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2019
·
IF 4.888
Lei Zhang,Hao Wang,Chengguang Yang,Xiaopeng Li,Jian Sun,Hui Wang,Peng Gao,Yuhan Sun
The present work reports on the promoting effects of rare earth elements (La, Ce and Y) to FeK/Al 2 O 3 catalysts on liquid hydrocarbons from CO 2 hydrogenation. The addition of La, Ce and Y can both improve the selectivity of C 5+ hydrocarbons and reduce the selectivity of CH 4 . The C 5+ selectivity can enhance to about 60 % with CH 4 selectivity of around 11 % at CO 2 conversions above 20 %. N 2 adsorption–desorption, in situ XRD, H 2 –TPR, CO 2 /H 2 –TPD, HRTEM and XPS are used to characterize the FeK/Al 2 O 3 and FeK/M-Al 2 O 3 (M = La, Ce, Y) catalysts. The results show that the introduction of rare earth elements into the FeK/Al 2 O 3 catalyst obviously reduces the adsorption of H 2 , which suppresses the CH 4 formation. On the other hand, rare earth elements also promote the adsorbed CO 2 species, which leads to the enhanced liquid hydrocarbons selectivity. Finally, the tailored CO 2 /H 2 ratio of CO 2 and H 2 adsorption on the catalyst surface can influence the catalyst activity and the product selectivity evidently.
研究领域:
催化化学
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材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 54
·48737-48744
·
IF 3.289
Danfeng Hou,Jiayu Xin,Xingmei Lu,Xiaonan Guo,Huixian Dong,Baozeng Ren,Suojiang Zhang
1,4-Cyclohexanedimethanol (CHDM) is a highly valued and widely used monomer in the polymer industry. Bis(2-hydroxyethylene terephthalate) (BHET), the product of glycolysis of waste PET, is an excellent raw material for the preparation of CHDM. Herein, a series of monometallic, bimetallic and trimetallic supported catalysts were prepared for the one-pot conversion of BHET into CHDM by the impregnation method and good performance was found over trimetallic RuPtSn/Al2O3 catalysts containing various active sites to catalyze the hydrogenation of the phenyl and carbonyl groups. The influences of various reaction parameters including temperature, pressure and time on the hydrogenation reaction were studied, and 100% conversion and 87.1% yield of CHDM were obtained with the trimetallic supported catalyst with Ru/Sn 1.5. Moreover, through the comparison between various methods for the preparation of CHDM, the conversion of BHET into CHDM by the one-pot method is considered one of the most competitive methods.
研究领域:
化学工程
·
材料科学
·
催化反应
✓ 已验证
DOI
高影响因子
CATALYSIS COMMUNICATIONS
·
2016
·
IF 3.389
Dapeng Liu,Anjie Wang,Chenguang Liu,Roel Prins
Bulk Ni 2 P and Al 2 O 3 -supported Ni 2 P were prepared at low phosphidation temperature (300 °C) from Ni 9 S 8 and NH 4 H 2 PO 2 , which were separated to avoid the formation of phosphate inside the support pores. The unsupported product phases were characterized by XRD and the Ni 2 P/Al 2 O 3 catalysts by XRD, BET and TEM. A 10 wt.% Ni 2 P/Al 2 O 3 catalyst, made by the Ni(NO 3 ) 2 –NiO–Ni 9 S 8 –Ni 2 P path at a P/Ni ratio of 3, showed the highest activity in the hydrodesulfurization of dibenzothiophene. By separating the nickel and hypophosphite sources, Ni 2 P/Al 2 O 3 catalysts could be obtained at low phosphidation temperature and with low degree of blockage of pores by surplus phosphorus.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Jie Li,Yan Zhang,Wenpo Shan,Hong He
A series of mesoporous Pd/Al 2 O 3 and Pd/MgAl 2 O 4 catalysts with different palladium contents (0.5, 1 and 4 wt%) were prepared by the impregnation method and used for methane combustion. Among the catalysts studied, 1Pd/MgAl 2 O 4 (1 wt% Pd) was found to be highly effective for the catalysis of CH 4 combustion below 450 °C, with a low apparent activation energy of ∼50.1 kJ/mol, and had good thermal stability. The characterization results showed that the excellent catalytic performance of Pd/MgAl 2 O 4 can be ascribed to the strong interaction between the MgAl 2 O 4 spinel and PdO species, favoring the dispersion and stability of the species. In addition, the effects of Pd particle size on CH 4 combustion were also investigated. It was found that the catalytic activity of Pd/MgAl 2 O 4 , with a strong metal-support interaction, showed a volcano-shaped dependence on the size of Pd particles.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）