Coatings
·
2019
·Vol. 9
·期 12
·867
·
IF 2.33
Diping Zeng,Zhiyi Liu,Song Bai,Jian Wang
In the present work, a coating was prepared on an Al alloy substrate by plasma electrolytic oxidation (PEO). To seal the micro defects in the oxide scale, a siloxane layer was prepared on the PEO coating by sol gel method. The polymer sealant was synthesized from Tetraethoxy silane (TEOS) and methacryloxy propyl trimethoxyl silane (MPTES). The chemical structure of the polymer was studied by Fourier transform infrared spectroscopy (FTIR). The morphologies and microstructure of the PEO coating and siloxane coating were investigated by scanning electron microscopy (SEM). The results showed that siloxane formed a continuous layer on the surface and effectively sealed the micro defects. The corrosion behavior of the coatings in three different corrosion solutions (NaCl, HCl, and NaOH) was examined by electrochemical impedance spectroscopy and potentiodynamic polarization. The corrosion resistance of the sealed coatings was superior to that of the PEO coating because it prevented the penetration of corrosive solutions. The corrosion resistance of the sealed coatings was found to decrease with increasing electrolyte concentration. The work demonstrated that siloxane sealing may greatly enhance the corrosion resistance of Al-based PEO coating in acidic, neutral, and alkaline environments.Keywords:PEO coating;silane polymer;sealing treatment;corrosion resistance
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高影响因子
Catalysis Science & Technology
·
2019
·Vol. 9
·期 24
·7034-7044
·
IF 5.726
Liwei Zhang,Huaike Zhang,Zhiqiang Chen,Qiang Ning,Suyao Liu,Jie Ren,Xiaodong Wen,Yong-Wang Li
To correlate the relationship between the Al distribution and the catalytic performance of long-chain olefin aromatization, several ZSM-5 zeolites with different Al locations and proximities were prepared via adjusting the hydrothermal synthesis conditions. Characterization by XRD, SEM and N2-adsorption indicated that all the as-prepared ZSM-5 zeolites exhibited high crystallinities, uniform morphologies and open channels. However, a great difference in the framework Al (AlF) positions was observed by 27Al MAS NMR and UV-vis-DRS of Co(II) ions, thus leading to the distinct acidity of various zeolites as determined by NH3-TPD and Py-IR. In 1-octene aromatization reaction, ZSM-5 catalysts exhibited significantly different catalytic performances and reaction pathways, which were closely related to the types and locations of the AlF atoms. The ZSM-5 zeolite catalyst with the most abundant single Al sites exhibited the lowest aromatics selectivity, while Al pairs in the framework were more favorable to the formation of aromatics. Moreover, the product distribution revealed that the Al pairs in the channel intersections of the ZSM-5 zeolite were responsible for the improved selectivity to heavy aromatics due to the fewer space restrictions; however, the Al pairs in the sinusoidal and straight channels with severe size restrictions suppressed the generation of bigger aromatics on the Al sites. This result provided a new potential method for precisely tailoring the catalytic selectivity in olefin conversion and upgrading the Fischer–Tropsch oil.
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FUEL
·
2022
·
IF 8.035
Rui Cao,Xueqian Wang,Ping Ning,Yibing Xie,Langlang Wang,Yixing Ma,Xiang Li,Hui Zhang,Jingye Liu
Basic sites are important to promote carbonyl sulfide (COS) and carbon disulfide (CS 2 ) hydrolysis activity while improving the oxidation resistance of hydrolysis catalysts is a challenge. Here, we report an N -doped alumina-based catalyst ( N -K@Al), where the complete hydrolysis removal of COS and CS 2 by the N -doped catalyst was extended up to 15 h at 160 °C, and the turnover frequency (TOF) value of the catalyst was increased from 0.85 × 10 -2 s −1 to 1.16 × 10 -2 s −1 . The results showed that the strong interaction between nitrogen and potassium decreased the reactive oxygen density and activated –OH, weakening the oxygen mobility. In addition, the beneficial effects of N -doped included the addition of moderately and weakly basic sites by pyridine N. The optimized N -K@Al showed good catalytic performance in the hydrolysis of COS and CS 2 removal with lower reaction temperature and higher total hydrogen sulfide yield. Density functional theory calculations revealed that N -K@Al reduced the Gibbs free energy of COS and CS 2 hydrolysis to 0.21 eV and 0.33 eV, respectively, contributing to the enhanced catalytic activity. The present study presents new strategies for developing efficient antioxidant organosulfur hydrolyzers and other practical industries.
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JOURNAL OF THERMAL SPRAY TECHNOLOGY
·
2023
·Vol. 32
·期 8
·2460-2477
·
IF 3.1
Wu Duoli,Wu Haotian,Yuan Ziyi,Wei Xinlong,Zhang Chao
To investigate the influence of Mo addition and water vapor content on the high-temperature corrosion resistance of Ni-Al-based coatings, 0Mo, 5Mo, and 10Mo coatings were deposited by APS thermal spray onto stainless steels. The chlorine-induced corrosion test was conducted in an experimental environment simulating a biomass boiler. The results show that adding the Mo element lowers the coating's ability to resist corrosion without water vapor. The coating is more prone to peeling because Mo prevents the coating from eventually forming a protective oxide layer. Water vapor significantly speeds up the production of oxides and modifies their morphology and structure. The combined effects of Mo and water vapor increase the coating's ability to resist corrosion. The development of thick and protective Ni and Al oxide layers on the coated surface is aided by the acceleration of oxide production by water vapor and the alteration of oxide structure by Mo components.
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LAB ON A CHIP
·
2023
·Vol. 23
·期 20
·4493-4503
·
IF 6.1
Wei Liu,Yongan Feng,Yapeng Yao,Zihang Liang,Fei Xiao,Zhongliang Ma
Integrating energetic materials with microelectromechanical systems (MEMS) to achieve miniaturized integrated smart energetic microchips has broad application prospects in miniaturized aerospace systems and civil explosive systems. In this work, MEMS compatible [Cu(BODN)·5H2O]n arrays and [Cu(BODN)·5H2O]n@nano-Al composite energetic films were successfully fabricated on copper substrates by the in situ reaction method and drop-coating method. Single crystal X-ray diffraction, powder X-ray diffraction, scanning electron microscopy, infrared spectroscopy, differential thermal analyses, and pulsed laser ignition were employed to characterize the prepared samples. The results show that [Cu(BODN)·5H2O]n arrays formed by the coordination reaction between the Cu(OH)2 template and the BODN ligand exhibit a porous supramolecular structure with excellent thermal and energy properties. Their morphology and composition on a copper substrate can be effectively regulated by adjusting the reaction time and solution concentration. In addition, adjustable energetic properties of [Cu(BODN)·5H2O]n@nano-Al composite films can be achieved after the encapsulation of nano-Al. Their heat release, flame height and ignition duration can reach as much as 1987.5 J g−1, 13.2 mm, and 5900 μs, respectively, indicating that [Cu(BODN)·5H2O]n@nano-Al can be used as an excellent pyrotechnic agent in MEMS ignition chips. Overall, this work provides a reference for the integration and application of energetic materials in MEMS systems.
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PubMed
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2023
·
IF 4.6
Enbo Li,Yu Bai,Peng Zhang,Hongxia Liu,Wen Ma,Yingwei Qi,Te Wang,Ziqian Zhang,Sinan Gao
Electronic structure adjustment on materials' surfaces often leads to materials obtaining novel performances. Flake Al powder is a classical low infrared emissivity material at room temperature. However, this powder shows intense infrared radiation over 500 °C due to its high-temperature oxidation , which restricts flake Al powder's application as low infrared radiation material in higher temperatures. For this reason, the Al@ZrO 2 composite was prepared by a solvothermal method to improve its thermostability. This composite can be used as low infrared radiation material over 500 °C for the long term, even at 700 °C for a short time. According to the experimental and theoretical investigation, a delocalization bond of Al–O–Zr is formed in the interface between the Al surface and ZrO 2 so that the Al surface's electronic structure is adjusted. This change of electronic structure weakens the electroaffinity of Al atoms to bond with the electron-rich groups, and the oxidation reaction of Al needs to proceed in a higher-temperature range. In this case, flake Al powder coating with ZrO 2 holds its metal properties with low infrared emissivity over 500 °C. The Al@ZrO 2 composite could be used in a higher temperature range as a low infrared radiation material.
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Jia Ma,Jiang-Hua Zhang,Hua-Wei Zhang,Qian-Qian Du,Zi-Xuan Li,Zhi-Fei Yang,Sha-Sha Yang,Da-Yong Zhou
It is of great importance to develop a most efficient, recyclable, and ecofriendly process to produce novel structured phospholipid emulsifiers. Herein, innovative medium-chain structured phospholipid (MCSPL) emulsifiers were synthesized through transesterification of soybean lecithins with medium-chain fatty acids (MCFAs) promoted by Zn- or Al-incorporated Fe 3 O 4 @SiO 2 , denoted by Fe 3 O 4 @SiO 2 /M (M = Zn or Al). Resultingly, Fe 3 O 4 @SiO 2 /M (M = Zn or Al) exhibited the most superior reactivity with 97.1% or 88.7% MCFA incorporation to other benchmark catalysts and also had excellent magnetic separability and recyclability. Noticeably, targeted MCSPLs possessed almost more superior emulsifying properties to other phospholipid emulsifiers, and had potential for use as oil–in–water emulsifiers. Conclusively, the present findings demonstrate that transesterification promoted by Fe 3 O 4 @SiO 2 /M (M = Zn or Al) can be a promising approach for green, economic, and highly effective synthesis of novel dual-function phospholipid emulsifiers with bioactive and emulsifying properties in food, pharmaceutical, and cosmetic industries.
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高影响因子
MATERIALS CHARACTERIZATION
·
2023
·
IF 4.7
Xudong Rong,Xiaofeng Chen,Dongdong Zhao,Xiang Zhang,Chunnian He,Chunsheng Shi,Naiqin Zhao
Age-hardening Al matrix composites (AMCs) exhibit great potential for developing advanced metal structural materials, while reinforcement configuration-dependent aging behaviors are still largely unclear. To gain an in-depth fundamental understanding of the effect of in-situ generated intragranular reinforcement on precipitation response, a systematical heat-treatment was applied for the in-situ generated Al 2 O 3 reinforced Al Cu composite prepared via powder metallurgical Al-5 wt% CuO (Al-5CuO) system. Results show that the nano-scale intragranular Al 2 O 3 activates the dislocation-assisted bulk diffusion pattern to promote the precipitation response, thus effectively shortening the peak-aging time of the composite as compared to the referenced Al-4 wt% Cu alloy matrix (Al 4Cu). The adequate precipitation within grains in the early-aging stage endows the peak-aged Al-5CuO composite with homogeneous size distribution of θ’ phase, contributing to the impressive mechanical properties . The mechanical analyses reveal that precipitation strengthening accounts for the prominent elevation of yield strength, while the enhanced ductility is achieved by decreasing the size and number density of precipitates segregated along reinforcement-matrix interface and grain boundary. This work yields new insights into intragranular reinforcement-driven precipitation response, which is crucial for designing age-hardening AMCs with high mechanical performance.
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DALTON TRANSACTIONS
·
2023
·Vol. 52
·期 35
·12296-12307
·
IF 4
Yan Wang,Yong Zhang,Xiaolin Liu,Sen Sun,Shiyi Qin,Jiaqi Huang,Bowei Chen
Herein, magnetic layered double oxides coated with carbon dots (MLCs) were synthesized through introducing sodium dodecylbenzene sulfonate and FeCl2 into Co/Al LDH for capturing uranium from aqueous solution. When the molar ratio of Co to Al was 4 : 1, the MLC composite possessed the strongest affinity to uranium(VI) in solution with short equilibrium time (<160 min), high adsorption efficiency (94.31%) and large removal capacity (513.85 mg g−1). The adsorption behavior of MLCs for uranium(VI) was well fitted with Langmuir and pseudo-second-order models, suggesting that the monolayer chemical adsorption was the rate-limiting step. Besides, MLC-3 could be reused by using 0.15 mol L−1 ethylene diamine tetraacetic acid as an eluent and the removal percentage still remained at a high level (>83.3%) after 5 adsorption/desorption cycles. Redox reaction, chemical complexation and electrostatic attraction were proved to play significant roles in uranium(VI) separation. Therefore, MLC-3 could be used as a potential adsorbent in uranium(VI)-containing wastewater treatment due to its excellent adsorption performance for uranium(VI).
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高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Xuewu Li,Shaomeng Du,Chenghu Ma,Tian Shi,Wei Qi,Hejie Yang
Improving the corrosion resistance of widely used Al alloys is important for expanding their industrial and marine applications. Structural fragility and preparation cost have always been key factors for restricting anticorrosive application of extensively-reported superhydrophobic surface. In order to try and fight that, combining with polyurethane (PU) adhesion agent, 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) was encapsulated around nano-SiO 2 ceramics for robust coating in place of conventional structure preparation strategy on Al alloy surface. Such low-cost one-step air-spraying SiO 2 @PFDTES@PU coating was prepared by 0.03 g nano-SiO 2 ceramics addition, 100 μL PFDTES and 0.25 g PU with the highest water contact angle of 168.34° ± 2.72°, a rolling angle of 4.02° ± 2.08°, and a propylene glycol oil contact angle of 156.52° ± 3.35°. FE-SEM, laser confocal microscopy, EDS and XPS were used to investigate micro-nano morphology and chemical composition of the coating. Meanwhile, the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements showed that as-prepared coating exhibited larger capacitive arc diameter, enhanced charge transfer resistance, larger |Z| 0.01Hz value, positive shifting E corr and significantly reduced I corr , thus demonstrating a significantly improved corrosion resistance. In addition, sandpaper friction experiment was used to evaluate the mechanical stability of the fabricated superhydrophobic coating. Ultimately, its resistance to solid/liquid contamination and self-cleaning ability were also systematically assessed. This work provides strong technical supports for industrial and marine applications for such low-cost, wear-resistant and anti-corrosion coating.
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Journal of Materials Research and Technology-JMR&T
·
2023
·
IF 6.4
Yang Yu,Baojing Zhang,Xiaoping Cai,Zhejian Cao,Farid Akhtar,Xinyang Jiao,Xueding Chai,Peizhong Feng
Ni–Al–Cr alloys in the β phase (B2–NiAl) region exhibit remarkable stability and mechanical property. Through thermal explosion (TE) reaction, Ni–Al–Cr intermetallic compounds with high porosity can be obtained. In this study, the focus lies on analyzing the macroscopic morphology, microstructure, phase distribution, TE behaviour, and the mechanical property of porous Ni–Al–Cr in the β phase region. Following the TE reaction, the Al-rich sintered product demonstrates a uniform phase composition and high porosity, reaching 44.39%. The vigorous TE reaction promotes the formation of interconnected pores, while the high porosity structure compromises the mechanical properties of the sample. Conversely, the Al-poor sintered product, due to a moderate TE reaction and low porosity structure, maintains its complete morphology and exhibits excellent compression resistance (yield stress reaching 538 MPa). This study offers valuable insights for the fabrication of porous Ni–Al–Cr materials with exceptional structure and performance.
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COMBUSTION AND FLAME
·
2023
·
IF 4.4
Yuxiang Li,Kaili Zhang
Metastable intermolecular composites (MICs) comprising solid fuels and oxidizers at nano-scale exhibit high energy densities and fast reaction speeds. As most metal and metalloid fuels are passivated by the natural oxide layer on the surface which acts as a reaction barrier, fluorine-containing oxidizers are of particular interest to promote the reactivity through interfacial fluoridation. In this work, cobalt hydroxy fluoride (Co(OH)F) was introduced as a functional fluorine-containing oxidizer, and core-shell structured Co(OH)F@Al nanoarray was fabricated onto a glass substrate . The thermal behavior and reaction mechanism of pure Co(OH)F and Co(OH)F@Al composites were thoroughly investigated, and Co(OH)F@Al was compared with CoO@Al and Co 3 O 4 @Al with identical morphology. In the Co(OH)F@Al composite, a pre-ignition reaction was observed which was attributed to the etching of Al 2 O 3 shell by HF and the fluoridation of Al core by HF and CoF 2 . With the assistance of pre-ignition reaction, Co(OH)F@Al can complete main exothermal reaction before Al melting in a solid-state mechanism, and its peak temperature is around 200 ℃ lower than those of MICs employing CoO and Co 3 O 4 as oxidizers.
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