SURFACE & COATINGS TECHNOLOGY
·
2021
·
IF 4.158
Zefei Yu,An Du,Chenyang Wang,Ruina Ma,Yongzhe Fan,Xue Zhao,Xiaoming Cao
Herein, a ZnO-doped plasma electrolytic oxidation (PEO) composite coating was prepared on the surface of a 1060 Al alloy by adding ZnO nanoparticles (ZnO-NPs) to the composite electrolytes of alkaline sodium silicate (Na 2 SiO 3 ) and sodium hexametaphosphate ((NaPO 3 ) 6 ). To efficiently investigate the coating's microstructure, the detached PEO coating was prepared without damage via an electrochemical method. The morphology and phase composition of the PEO coating were analyzed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray diffraction (XRD), and an incorporation model of ZnO-NPs was established. The results showed that the addition of ZnO-NPs slightly prolonged the anodic oxidation time and increased the breakdown voltage, whereas the working voltage and final voltage decreased slightly. The XRD results indicated that although the addition of ZnO-NPs did not result in the production of Zn-containing phases, it affected the formation and transformation reactions of other phases. SEM micrographs of the fractured cross-section of detached coating and coating/substrate interface indicated that the ZnO-NPs did not enter the interface layer, nor did it participate in the formation of the cap structure at the interface. Based on the experimental results and the “cascade discharge” model, an incorporation model of ZnO-NPs in PEO has been proposed.
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DOI
高影响因子
Science China-Materials
·
2023
·Vol. 66
·期 11
·4295-4305
·
IF 8.1
Rong Xudong,Li Yue,Chen Xiaofeng,Zhang Xiang,Zhao Dongdong,He Chunnian,Zhao Naiqin
Incorporating reinforcements can improve the mechanical properties of Al matrix composites but make them susceptible to corrosion attacks by facilitating the formation of a galvanic cell network along the interface. The optimization of the interfacial structure improves the corrosion resistance of the composites. Herein, a solid-state thermite reaction integrated with a heat treatment strategy was developed to create plain interfaces, encompassing the grain boundary (GB) and reinforcement–matrix interface, in an Al–CuO composite system. The intergranular corrosion behavior and susceptibility to stress corrosion cracking of the composite were comprehensively examined by immersion/electrochemical corrosion tests and microstructural characterizations. The intragranular distribution of nanosized secondary phases, i.e., Al 2 O 3 and precipitates, was investigated to address their contribution to the continuous galvanic cell detachment along the GBs and interruption of the corrosion path, thus boosting the corrosion duration. In addition, the tightly bonded Al 2 O 3 –Al interface with low strain energy distinctly lowers local susceptibility to corrosion. This study illuminates the correlation between interface characteristics and corrosion mechanisms in the composites, which can shed light on the development of high-corrosion-resistant composites.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Peibo Li,Guoqiang Luo,Guinan Zhao,Huawu Liu,Yi Sun,Qiang Shen
Al powder is prone to oxidation, which can introduce impurities in powder metallurgy. In this study, Al 2 O 3 nanonetworks were obtained by destroying the oxide layer through Paulse Activated Sintering (PAS). The network and the nano-precipitation enhance the mechanical properties of Al-Cu-O composites. TEM analysis revealed the formation of CuAl 2 and an Al 2 O 3 network at the grain boundaries. The current facilitated the modulation of the intermetallic compound size and the fragmentation of the oxide layer. The current-induced discharge at the particle interfaces generated localized heating. Higher temperature effectively disrupts the oxide layer. The Al 2 O 3 network improved the fracture toughness of the Al-Cu-O composites by passivating crack propagation. Simultaneously, the current reduced the nucleation barrier for precipitation by promoting directional atomic migration. Uniformly dispersed nano-precipitates are conducive to the improvement of strength. This study provides new insights into oxidation-related challenges in Al powder.
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产品关联
DOI
高影响因子
Nanomaterials
·
2020
·Vol. 10
·期 3
·438
·
IF 4.324
Jianian Hu,Jian Zhang,Guoqiang Luo,Yi Sun,Qiang Shen,Lianmeng Zhang
This research presents an approach for C-O grain boundary strengthening of Al composites that used an in situ method to synthesize a C-O shell on Al powder particles in a vertical tube furnace. The C-O reinforced Al matrix composites (C-O/Al composites) were fabricated by a new powder metallurgy (PM) method associated with the hot pressing technique. The data indicates that Al4C3was distributed within the Al matrix and an O-Al solution was distributed in the grain boundaries in the strengthened structure. The formation mechanism of this structure was explained by a combination of TEM observations and molecular dynamic simulation results. The yield strength and ultimate tensile strength of the C-O/Al composites, modified by 3 wt.% polyvinyl butyral, reached 232.2 MPa and 304.82 MPa, respectively; compared to the yield strength and ultimate tensile strength of the pure aluminum processed under the same conditions, there was an increase of 124% and 99.3%, respectively. These results indicate the excellent properties of the C-O/Al-strengthened structure. In addition, the strengthening mechanism was explained by the Hall–Petch strengthening, dislocation strengthening, and solid solution strengthening mechanisms, which represented contributions of nearly 44.9%, 15.9%, and 16.6% to the total increased strength, respectively. The remaining increment was attributed to the coupled strengthening of the C and O, which contributed 20.6% to the total increase.
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高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2015
·Vol. 117
·期 1
·239-251
·
IF 1.17
Geng Gaoli,Wei Ruiping,Liang Ting,Zhou Minghao,Xiao Guomin
A series of Cu–Ca–Al hydrotalcite derived catalysts were prepared by the co-precipitation method. Their catalytic activities were evaluated in the hydrogenolysis of glycerol. The catalysts were characterized by XRD, SEM, TEM, ICP, NH 3 -TPD, CO 2 -TPD and H 2 -TPR. It was observed that the incorporation of calcium and aluminum in the Cu–Ca–Al catalyst improved the conversion of glycerol and promoted the generation of 1,3-PDO. This is due to the appropriate acidity and basicity of the catalyst, which is confirmed by NH 3 -TPD and CO 2 -TPD. The conversion of glycerol over the catalyst with a Cu–Ca–Al mole ratio of 1:3:5 was up to 73.2 % with 42.6 % selectivity to 1,2-PDO and 9.1 % selectivity to 1,3-PDO. Effects of the reaction time, reaction temperature and initial hydrogen pressure on the conversion and selectivity were systematically investigated.
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高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2020
·Vol. 35
·期 3
·514-519
·
IF 0.64
Liu Tingling,Pang Xiaoxuan,Xian Yajiang,Luo Hao,Zhang Pengcheng
Aluminum-matrix boron carbide (B 4 C p /Al) is a kind of neutron absorbing material widely used in nuclear spent fuel storage. In order to improve the tensile property of B 4 C p /Al composites, a new type of nano-Al 2 O 3 particle (Al 2 O 3np ) reinforced B 4 C p /Al + Al 2 O 3np composites were prepared by powder metallurgy method. The Monte Carlo particle transport program (MCNP) was used to determine the influence of Al 2 O 3np on the thermal neutron absorptivity of composites. The universal material testing machine and scanning electron microscope (SEM) were used to study the mechanical properties, microstructure and fracture morphology of B 4 C p /Al composites. The results indicated that the neutron absorption properties of B 4 C p /Al composites were not affected by the addition of nano-Al 2 O 3 particles in the range of 1 wt%–15 wt%. The addition of Al 2 O 3np can obviously reduce the grain size of B 4 C p /Al matrix metals thus improve the tensile strength of the composites. The addition threshold of Al 2 O 3np is about 2.5 wt%. Both B 4 C p and Al 2 O 3np change the fracture characteristics of the composites from toughness to brittleness, and the latter is more important.
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高影响因子
DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 6
·2538-2546
·
IF 4.569
Xingyu Liu,Xiaoyue Wang,Rui Miao,Yanzhi Sun,Yongmei Chen,Yang Tang,Pingyu Wan,Junqing Pan
Metal organic frameworks (MOFs) and their derivatives have been widely used in electrochemistry due to their adjustable pore size and high specific surface area (SSA). Herein, a spindle-like hierarchical porous activated carbon (SPC) was synthesized through carbonizing the Al-BTEC precursor and then alkaline washing with NaOH. The fabricated SPC has a uniform shuttle-shaped structure, showing a large BET surface area of 1895 m2 g−1 and an average pore size of 2.4 nm. The SPC product displays a high specific capacitance (SC) of 337 F g−1 at 1 mV s−1 and 334 F g−1 at 1 A g−1. The retention of SC is about 95% after 100 000 cycles when the current density is 50 A g−1, indicating its excellent stability. Furthermore, the assembled symmetrical capacitor with a two-electrode system exhibits a high SC of 173 F g−1 at 1 A g−1 and an energy density of 15.3 W h kg−1 at a power density of 336 W kg−1. This work would provide a new pathway to design and synthesize carbon materials for supercapacitors with excellent properties in the future.
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DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Jun Cheng,Wenjie Lin,Jingrong Hou,Yaqi Liao,Yunhui Huang
As the classic cathode material, lithium cobalt oxide (LiCoO2, LCO) suffers from severe structural and interfacial degradation at voltage >4.5 V, which induces fast capacity decay of the cells. Herein, we adopt a simple and effective method, doping aluminum (Al) cations in precursors, to improve the structural stability of LCO and systematically investigate the effect of Al doping on the electrochemical performances. Doping in precursors rather than bulk particles is beneficial to realize uniform Al ions distribution. Even at 4.5 V charging voltage, the LCO/graphite pouch cells with high Al doping levels (8500 ppm) deliver initial and reversible discharge capacities of 386 and 369 mAh after 500 cycles, respectively. The capacity retention is as high as 95.5%. When the cutoff voltage reaches 4.55 V, the pouch cell maintains 79.0% of the first-cycle discharge capacity after 500 cycles. With optimized electrolyte, the pouch cell realizes 87.3% of the initial discharge capacity after 500 cycles at 45 °C. Moreover, the thermal safety performance of the pouch cells with Al doping is promising. Our work displays an excellent inspiration for developing high-voltage, long-cycle, and safe LCO cathode for commercial lithium-ion batteries.
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DOI
高影响因子
Materials Research Express
·
2019
·Vol. 6
·期 10
·105316
·
IF 1.449
Ruoyu Liu,Chuanbing Huang,Lingzhong Du,Hao Lan,Shige Fang,Weigang Zhang
Aluminium/polyimide (Al/PI) powders were prepared via in situ. Al/PI composites were fabricated by hot pressing technology at 723 K for 30 min under Ar. The microstructure, thermal stability and tribological properties of Al/PI composites were investigated. SEM images showed that Al particles were wrapped in the composite with no gap. According to the TG analysis, 15Al/PI composite showed excellent thermal stability up to 773 K. Meanwhile, 15Al/PI composites exhibited excellent tribological behaviour at high temperature, especially at 773 K. The friction coefficient of 15Al/PI composite at 773 K was about 0.28 which was lower than that of pure PI (about 0.41). The wear rate of 15Al/PI composite at 773 K was about 65 × 10−5 mm3 Nm−1. The tribological properties of Al/PI composites was improved at high temperature. In the process of sliding tests, Al particles were transferred to the Ti-6Al-4V alloy's surface and PI particles were pressed on the composite's surface. The transfer of Al can protect Ti-6Al-4V alloy from wear and reduce the friction coefficient during the sliding test.
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高影响因子
JOURNAL OF POWER SOURCES
·
2014
·
IF 5.211
Yanhua Zhang,Fei Chen,Rong Tu,Qiang Shen,Lianmeng Zhang
High performance lithium ion conducting Li 7 La 3 Zr 2 O 12 solid electrolytes are prepared for the first time by field assisted sintering technology (FAST). The effect of sintering temperature on the phase compositions , microstructure and Li ionic conductivity is systematically investigated. The results show that pure cubic phase LLZO can be obtained at a range of temperatures from 1100 to 1180 °C for no more than 10 min. For the sample sintered at 1150 °C, a maximum relative density of 99.8% with a total ionic conductivity as high as 5.7 × 10 −4 S cm −1 are obtained at room temperature . This value is the highest among the present research. Compared with the traditional preparation methods, the current FAST is very promising to obtain high performance LLZO for its advantages of very short sintering time , a single preparation step of reaction-densification processing, and relatively lower sintering temperature.
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高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Yaofeng Mao,Qianqian He,Jun Wang,Zijian Li,Zhijian Yang,Fude Nie,DunJu Wang
Polytetrafluoroethylene/Aluminum (PTFE/Al) composite with high energy density and combustion reaction performance has received widespread attention in the field of propellants, explosives, and pyrotechnics. In order to precisely control combustion reaction and energy output performance, gradient structured PTFE/Al composite (mass and diameter gradient) has been designed and constructed through 3D printing technology . PTFE/Al ink is prepared by acoustic resonance mixing to control rheological properties (viscosity and modulus) for 3D printing technology. The largest reaction heat (7749.95 J/g) and burning rate (~130 mm/s) are achieved for gradient lines with diameter of 2.42 mm and mass ratio of 60:40 (PTFE/Al). Moreover, the progressive change from steady combustion to deflagration containing three stages of pressure output is observed for gradient structured PTFE/Al cylinder. This work reveals that gradient structure could provide new strategy to tune energy output and combustion performances, which can promote the practical application of PTFE/Al reactive materials.
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DOI
高影响因子
Defence Technology
·
2020
·
IF 2.637
Yue-ting Wang,Xiao-ting Zhang,Jian-bing Xu,Yun Shen,Cheng-ai Wang,Fu-wei Li,Ze-hua Zhang,Jian Chen,Ying-hua Ye,Rui-qi Shen
In this study, Al–CuO nanocomposites were fabricated by sol-gel method. As a contrast, the thermite was prepared by physical mixing at the equivalence ratio of 0.5, 1, 2, respectively. The intermediates and samples as prepared were characterized by SEM and XRD. The exothermic properties of the two samples prepared at different equivalence ratios were tested and the reaction products were characterized by XRD. The SEM results show that the sample prepared by the sol-gel method demonstrates a micron-sized agglomerated sphere formed by a mutual wrapping of Al NPs and CuO NPs, and the particles are evenly distributed in the agglomerate. In addition, when the content of Al powder is seriously insufficient, the heat release of the sample prepared by physical mixing is 1.6 times that of by sol-gel method. With the increase of Al powder content, the exothermic properties of Al/CuO NPs prepared by sol-gel method began to increase significantly compared with physical mixing and the difference is 1.5 times when the equivalence ratio increases to 2. It can be concluded that the reason for this result may be attributed to the different mass transfer modes of components due to the different morphologies of samples.
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高影响因子
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