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Influence of Aging Time on Microstructure and Corrosion Behavior of a Cu-Bearing 17Cr–1Si–0.5Nb Ferritic Heat-Resistant Stainless Steel

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Acta Metallurgica Sinica(English Letters) 2020年第9期33卷 1289-1301页

作者： Tong Zhang Ying Han Wen Wang Yang gao Ying Song Xu Ran Key Laboratory of Advanced Structural Materials Ministry of EducationChangchun University of TechnologyChangchun 130012China School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi’an 710055China

17 Cr–1 Si–0.5 Nb–1.2 Cu ferritic heat-resistant stainless steel was aged at 750 °C from 10 min to 30 h to simulate time aging and study the microstructural evolution and its effect on corrosion behavior by using optical microscopy, scanning electron microscopy, transmission electron microscopy, potentiodynamic polarization, electrochemical impedance spectroscopy, and the Mott–Schottky approach. Four types of precipitates were discovered, including ε-Cu, NbC, Fe3 Nb3 C, and Fe2 Nb-type Laves phase. The nano-sized ε-Cu phase forms first, and its fraction follows the parabolic law change and is the largest. Compared to NbC and Fe3 Nb3 C particles, the coarsening of the Laves phase is the most pronounced. The aging process is divided into three parts: early-aged(0–5 h), peak-aged(5 h), and over-aged(5–30 h). However, the corrosion resistance is reduced in the early-aged stage of 0–2 h. Further extending the aging time to 30 h, the corrosion resistance is gradually improved. This change may be related to the competitive relationship between the beneficial effects of the Cu-rich phase and the harmful effects of Nb-containing particles. The dissolved Cu on the surface becomes more effective for the suppression of the anodic dissolution by the formation of ionic compounds of chlorine, thereby reducing the deterioration of corrosion resistance caused by Nb-rich precipitation.

关键词： Ferritic stainless steel Aging Precipitation Electrochemical behavior Passive film

Improved Plasmonic Hot‑Electron Capture in Au Nanoparticle/Polymeric Carbon Nitride by Pt Single Atoms for Broad‑Spectrum Photocatalytic H_(2)Evolution

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Nano-Micro Letters 2023年第8期15卷 423-435页

作者： Manyi gao Fenyang Tian Xin Zhang Zhaoyu Chen Weiwei Yang Yongsheng Yu MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001HeilongjiangPeople’s Republic of China Space Environment Simulation Research Infrastructure Harbin Institute of TechnologyHarbin 150001People’s Republic of China

ABSTRACT Rationally designing broad-spectrum photocatalysts to harvest whole visible-light region photons and enhance solar energy conversion is a“holy grail”for researchers,but is still a challenging ***,based on the common polymeric carbon nitride(PCN),a hybrid co-catalysts system comprising plasmonic Au nanoparticles(NPs)and atomically dispersed Pt single atoms(PtSAs)with different functions was constructed to address this *** the dual co-catalysts decorated PCN(PtSAs–Au_(2.5)/PCN),the PCN is photoexcited to generate electrons under UV and short-wavelength visible light,and the synergetic Au NPs and PtSAs not only accelerate charge separation and transfer though Schottky junctions and metal-support bond but also act as the co-catalysts for H_(2) ***,the Au NPs absorb long-wavelength visible light owing to its localized surface plasmon resonance,and the adjacent PtSAs trap the plasmonic hot-electrons for H_(2) evolution via direct electron transfer ***,the PtSAs–Au_(2.5)/PCN exhibits excellent broad-spectrum photocatalytic H_(2) evolution activity with the H_(2) evolution rate of 8.8 mmol g^(−1) h^(−1) at 420 nm and 264μmol g^(−1) h^(−1) at 550 nm,much higher than that of Au_(2.5)/PCN and PtSAs–PCN,*** work provides a new strategy to design broad-spectrum photocatalysts for energy conversion reaction.

关键词： Polymeric carbon nitride Au nanoparticles Pt single atoms Photocatalytic H2 evolution Broad-spectrum photocatalysts

Influence of topography on the fine structures of stratospheric gravity waves:An analysis using COSMIC-2 temperature data

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Earth and Planetary Physics 2024年第3期8卷 497-513页

作者： JiaRui Wei Xiao Liu JiYao Xu QinZeng Li Hong gao State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Institute of Electromagnetic Wave School of PhysicsHenan Normal UniversityXinxiang Henan 453000China

We derive the potential energy of gravity waves(GWs)in the upper troposphere and stratosphere at 45°S-45°N from December 2019 to November 2022 by using temperature profiles retrieved from the Constellation Observing System for Meteorology,Ionosphere,and Climate-2(COSMIC-2)*** to the dense sampling of COSMIC-2,in addition to the strong peaks of gravity wave potential energy(GWPE)above the Andes and Tibetan Plateau,we found weak peaks above the Rocky,Atlas,Caucasus,and Tianshan *** land-sea contrast is responsible for the longitudinal variations of the GWPE in the lower and upper *** 40°N/S,the peaks were mainly above the topographic regions during the *** 20°N/S,the peaks were a slight distance away from the topographic regions and might be the combined effect of nontopographic GWs and mountain *** the Equator,the peaks were mainly above the regions with the lowest sea level altitude and may have resulted from *** results indicate that even above the local regions with lower sea level altitudes compared with the Andes and Tibetan Plateau,the GWPE also exhibits fine structures in geographic *** found that dissipation layers above the tropopause jet provide the body force to generate secondary waves in the upper stratosphere,especially during the winter months of each hemisphere and at latitudes of greater than 20°N/S.

关键词： topography fine structures stratospheric gravity waves Constellation Observing System for Meteorology Ionosphere and Climate-2(COSMIC-2) dissipation layers

Highly reversible Zn anode enabled by anticatalytic carbon layer with suppressed hydrogen evolution

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Rare Metals 2024年第7期43卷 3044-3054页

作者： Wen-Duo Zhang Chuang Sun Yu-Xuan Zhu Feng gao Chao Lai School of Chemistry and Materials Science Jiangsu Normal UniversityXuzhou221116China

Aqueous zinc-ion batteries(AZIBs)have emerged as a promising high-efficiency energy storage system due to the high energy density,low-cost and environmental ***,the practical application of AZIBs is severely restricted by the challenges faced by the Zn anode,which include uncontrollable dendrite growth,corrosion and hydrogen evolution ***,a simple and convenient physical vapor deposition(PVD)method is reported for fabricating uniform graphite as a protection layer on the surface of Zn *** high conductivity graphite layer on Zn anode(denoted as Zn@C)not only benefits the uniform distribution of the electric field,but also provides numerous Zn nucleation sites to regulate and navigate Zn-ion stripping/plating ***,the graphite layer with a poor catalytic activity endows the Zn@C anode with a highly suppressed hydrogen ***,a hydrogen and dendrite free anode is achieved with artificial anticatalytic carbon layer on Zn anode,exhibiting a high reversibility and excellent cycling stability over 2600 h at the current density of 5 mA·cm^(-2)with a capacity of 2.5 mAh·cm^(-2)and longtime cycling stability for assembled full *** work strategically designs the properties of the artificial interface layer to effectively address various challenges simultaneously,which presents insights for the future development of high-performance rechargeable AZIBs.

关键词： Zn metal anode Artificial anticatalytic layer Hydrogen suppression Dendrite free

Investigation on insulation properties of HFO-1336mzz(E)and N_(2)/CO_(2)mixtures as SF_(6) substitutes in gas-insulated electrical applications

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High Voltage 2023年第1期8卷 48-58页

作者： Zhanyang gao Yunbai Luo Ruichao Peng Xiaoxiao Wang Ping Yu Wenjun Zhou Engineering Research Center of Organosilicon Compounds&Materials Ministry of EducationCollege of Chemistry and Molecular SciencesWuhan UniversityWuhanChina School of Electrical Engineering and Automation Wuhan UniversityWuhanChina

The emissions of SF6 have been restricted owing to 3400 years of atmospheric lifetime and high global warming potential(GWP)as an insulating gas in gas-insulated electrical *** this study,HFO-1336mzz(E)and N_(2)/CO_(2)mixtures are proposed as SF6 substitutes for their short atmospheric lifetime,low GWP and superior insulation *** GWP of HFO-1336mzz(E)is only 18 and its atmospheric lifetime is days to *** breakdown voltage of 25%HFO-1336mzz(E)and N_(2)/CO_(2)mixtures is about 85%that of pure SF6 under alternating *** self-recovery ability of HFO-1336mzz(E)and CO_(2)mixtures is superior to that of HFO-1336mzz(E)and N_(2)*** decomposition characteristic of HFO-1336mzz(E)shows that a tiny amount of its gas might initiate a carbonisation reaction to form carbon after multiple breakdown tests,which is verified by observations using energy dispersive X-rays spectroscopy and scanning electron *** acute toxicity test of HFO-1336mzz(E)indicates that the gas is *** results show that HFO-1336mzz(E)and N_(2)/CO_(2)mixtures are potential substitutes for SF6 in electrical applications.

关键词： SF6 electrical insulation

Separation of galena and chalcopyrite using the difference in their surface acid corrosion characteristics

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International Journal of Minerals,Metallurgy and Materials 2023年第11期30卷 2157-2168页

作者： Haiyun Xie Jialing Chen Pei Zhang Likun gao Dianwen Liu Luzheng Chen Faculty of Land and Resources Engineering Kunming University of Science and TechnologyKunming 650093China Yunnan Key Laboratory of Green Separation and Enrichment of Strategic Mineral Resources Kunming 650093China

Galena(PbS)and chalcopyrite(CuFeS_(2))are sulfide minerals that exhibit good floatability ***,efficiently separating them via common flotation is ***,a new method of surface sulfuric acid corrosion in conjunction with flotation separation was proposed,and the efficient separation of galena and chalcopyrite was successfully *** angle test results showed a substantial decrease in surface contact angle and a selective inhibition of surface floatability for corroded ***,the contact angle and floatability of corroded chalcopyrite remained almost *** electron microscope results confirmed that sulfuric acid corrosion led to the formation of a dense oxide layer on the galena surface,whereas the chalcopyrite surface remained unaltered.X-ray photoelectron spectroscopy results showed that the chemical state of S^(2-)on the surface of corroded galena was oxidized to SO_(4)^(2-).A layer of hydrophilic PbSO4was formed on the surface,leading to a sharp decrease in galena ***,new hydrophobic CuS_(2),CuS,and Cu_(1-x)Fe_(1-y)S_(2-z)species exhibiting good floatability were generated on the chalcopyrite ***,theoretical analysis results were further verified by corrosion–flotation separation *** galena–chalcopyrite mixture was completely separated via flotation separation under appropriate corrosion acidity,corrosion temperature,and corrosion time.A novel approach has been outlined in this study,providing potential applications in the efficient separation of refractory copper–lead sulfide ore.

关键词： surface acid corrosion galena chalcopyrite flotation separation efficiency

Formability enhancement in hot spinning of titanium alloy thin-walled tube via prediction and control of ductile fracture

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Chinese Journal of Aeronautics 2022年第2期35卷 320-331页

作者： Pengfei gao Chao YU Mingwang FU Lu XING Mei ZHAN Jing GUO State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of High-Performance Precision Forming Technology and EquipmentSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHung HornKowloonHong Kong 999077China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China

The damage and fracture in hot spinning of titanium alloy is a very complex process under the combined effects of microstructure evolution and stress *** this study,their dependences on processing parameters were investigated by an integrated FE model considering microstructure and damage evolution,and revealing the effects of microstructure and stress states on damage *** results show that the inner surface of workpiece with the largest voids volume fraction is the place with the greatest potential of *** is mainly attributed to the superposition effects of positive stress triaxiality and the smallest dynamic recrystallization(DRX)fraction andβphase fraction at the inner *** damage degree is decreased gradually with the increase of initial spinning temperature and roller fillet ***,it is first decreased and then increased with the increases of spinning pass and roller feed rate,which can be explained based on the variations ofβphase fraction,DRX fraction,stress state and tensile plastic strain with processing *** addition,the dominant influencing mechanisms were identified and ***,the thickness reduction without defect in the hot spinning of TA15 alloy tube is greatly increased by proposing an optimal processing scheme.

关键词： Control of ductile fracture Dynamic recrystallization Forming limit Hot spinning Titanium alloy tube

Silicon-processes-compatible contact engineering for twodimensional materials integrated circuits

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Nano Research 2023年第11期16卷 12471-12490页

作者： Li gao Zhangyi Chen Chao Chen Xiankun Zhang Zheng Zhang Yue Zhang Academy for Advanced Interdisciplinary Science and Technology Beijing Advanced Innovation Center for Materials Genome EngineeringUniversity of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Peking UniversityBeijing 100871China Key Laboratory of Advanced Materials and Devices for Post-Moore Chips Ministry of EducationUniversity of Science and Technology BeijingBeijing 100083China

Two-dimensional(2D)semiconductors,especially transition metal dichalcogenides(TMDCs),have been proven to be excellent channel materials for the next-generation integrated circuit(IC).However,the contact problem between 2D TMDCs and metal electrodes has always been one of the main factors restricting their *** this review,we summarized recent work on 2D TMDCs contact from the perspective of compatible integration with silicon processes and practical application requirements,including the contact performance evaluation indicators,special challenges encountered in 2D TMDCs,and recent optimization ***,we sorted out and highlighted the performance indicators of 2D TMDCs contacts,including contact resistance(RC),contact scaling,contact stability,and contact electrical/thermal *** challenges of 2D TMDCs and metal contact,such as severe Fermi level pinning,large RC,and difficult doping,are systematically ***,typical methods for optimizing 2D TMDCs RC,edge contact strategies for scaling contact lengths,and solutions for improving contact stability are *** on the current research and problems,the development direction of 2D TMDCs contacts that meet the silicon-based compatible process and application performance requirements is proposed.

关键词： two-dimensional(2D)semiconductors transition metal dichalcogenides field effect transistors contact engineering

Fundamental solutions of critical wedge angles for one-dimensional piezoelectric quasicrystal wedge

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Applied Mathematics and Mechanics(English Edition) 2022年第5期43卷 709-728页

作者： Xiang MU Xiaoyu FU Liangliang ZHANG Zhaowei ZHU Jinming ZHANG Yang gao College of Science China Agricultural UniversityBeijing 100083China College of Engineering China Agricultural UniversityBeijing 100083China

Two problems of a one-dimensional(1D)piezoelectric quasicrystal(QC)wedge are investigated,i.e.,the two sides of the wedge subject to uniform tractions and the wedge apex subject to the concentrated *** virtue of the Stroh formalism and Barnett-Lothe matrices,the analytical expressions of the displacements and stresses are derived,and the generalized solutions for the critical wedge angles are *** examples are given to present the mechanical behaviors of the wedge in each *** results indicate that the effects of the uniform tractions and the concentrated force on the phonon field displacement are larger than those on the phason field.

关键词： quasicrystal(QC) wedge piezoelectric effect critical angle analytical solution