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Review of solution growth techniques for 4H-SiC single crystal

China Foundry 2023年第2期20卷 159-178页

作者： Gang-qiang Liang Hao Qian Yi-lin Su Lin Shi Qiang Li Yuan Liu School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology(Ministry of Education) Beijing 100084China

Silicon carbide(SiC),a group IV compound and wide-bandgap semiconductor for high-power,high-frequency and high-temperature devices,demonstrates excellent inherent properties for power devices and specialized high-end *** growth is thermodynamically favorable for producing SiC single crystal ingots with ultra-low dislocation density as the crystallization is driven by the supersaturation of carbon dissolved in Si-metal ***,solution growth is conducive to the growth of both N-and P-type SiC,with doping concentrations ranging from 10^(14)to 10^(19)cm^(-3).To date,4-inch 4H-SiC substrates with a thickness of 15 mm produced by solution growth have been unveiled,while substrates of 6 inches and above are still under *** on top-seeded solution growth(TSSG),several growth techniques have been developed including solution growth on a concave surface(SGCS),melt-back,accelerated crucible rotation technique(ACRT),two-step growth,and facet ***-parameters of the solution growth including meniscus,solvent design,flow control,dislocation conversion,facet growth,and structures of graphite components make high-quality single crystal growth *** this paper,the solution growth techniques and corresponding parameters involved in SiC bulk growth were reviewed.

关键词： wide-bandgap semiconductor silicon carbide bulk growth of single crystal process parameters

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A new thiol-sulfur click chemistry for lithium-organosulfide batteries

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The Innovation 2025年第2期6卷 42-48,41页

作者： Rong Zou Wenwu Liu Fen Ran State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Department of Polymeric Materials EngineeringSchool of Materials Science and EngineeringLanzhou University of TechnologyLanzhou 730050China

Click chemistry is a rapid,reliable,and powerful function and a highly selective organic reaction that facilitates the efficient synthesis of various molecules by joining small *** approach has found widespread applications in fields such as drug development,chemical synthesis,and molecular *** recent years,the reaction of alkali-catalyzed polymerization of thiol and sulfur has been employed to prepare various sulfur-containing polymers,which are applied as electrochemical active electrode materials in the pursuit of good *** this study,it is surprising to find that the reaction mechanism exhibits characteristics of both the alkali-catalyzed sulfhydryl Micheal addition reaction and thiol-epoxy click chemistry;for the first time,thiol-sulfur click chemistry is defined in detail,providing a comprehensive description of its underlying scientific *** introduction of this new reaction pathway holds significant potential for advancing research and the development of sulfur-containing *** on this novel click chemistry,a new sulfur-containing polymer,polydivinylthioether hexasulfide,has been designed and successfully applied as a cathode material in lithium-organosulfide *** material demonstrates excellent electrochemical performance,achieving an initial capacity that reaches 790.5 mAh g−1(82.6%of theoretical capacity),and in a long-term cycle test,the capacity decay rate is only 0.063%after 1,000 cycles.

关键词： electrochemical active electrode mater thiol sulfur click chemistry molecular biologyin lithium organosulfide batteries synthesis various molecules organic reaction click chemistry joining small unitsthis

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Ultrathin GaN Film Derived from Amorphous Ga_(2)O_(3) Film

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Journal of Wuhan University of Technology(materials Science) 2024年第4期39卷 814-818页

作者：王鹏 ZHANG Binbin LIU Xiaofei ZHANG Xin TU Rong ZHANG Song 李宝文 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Silicate Materials for Architectures School of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070China

It remains a big challenge to synthesize two-dimensional(2D)GaN material for applications in power *** synthetic methods require complex equipment and processes and time ***,we reported a two-step route to prepare polycrystalline 2D GaN *** amorphous ultrathin Ga_(2)O_(3)film was first exfoliated from the surface of liquid *** a vapor phase reaction,2D Ga_(2)O_(3)film was then converted into 2D GaN film while maintaining the 2D *** and high-resolution transmission electron microscope(HRTEM)analysis implies the successful synthesis of wurtzite-type GaN ultrathin *** simple strategy proposed in this work will provide more opportunities for applications of GaN ultrathin film in many devices.

关键词： GaN Ga_(2)O_(3) liquid gallium

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Generation and Suppression of Pendant Droplet Oscillation in Electron Beam Directed Energy Deposition

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engineering 2024年第6期37卷 215-229页

作者： Zhiyue Liang Zhenyu Liao Haoyu Zhang Zixiang Li Li Wang Baohua Chang Dong Du Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationTsinghua UniversityBeijing 100084China

Electron beam–directed energy deposition(EB–DED)has emerged as a promising wire-based metal additive manufacturing ***,the effects of EBs on pendant droplets at wire tips have not yet been *** aim of this study is to enhance the understanding of this action by analyzing the mechanism of droplet *** pendant droplet oscillation phenomenon hinders the stable transfer of droplets to the molten pool and limits the feasibility of manufacturing complex lattice structures by EB–***,another aim of this study is to create an oscillation suppression *** escalating asymmetric amplitude is the main characteristic of droplet *** primary oscillationinducing force is the recoil force generated from the EB-acted local surface of the *** physical mechanism of this force is the rapid increase and uneven distribution of the local surface temperature caused by the partial action of the *** prerequisites for droplet oscillation include vacuum conditions,high power densities,and bypass wire feeding *** proposed EB–dynamic surrounding melting(DSM)method can be applied to conveniently and effectively suppress oscillations,enable the accurate transfer of droplets to the molten pool,and achieve stable processes for preparing the strut elements of lattice *** the temperature and improving the uniformity of its distribution are the mechanisms of oscillation suppression in EB–*** this study,the physical basis for interpreting the mechanism by which EBs act on droplets and the technical basis for using EB–DED to prepare complex lattice structure parts are provided.

关键词： Additive manufacturing Electron beam freeform fabrication In situ monitoring Pendant droplet

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Polymer composites designed with 3D fibrous CNT“tracks”achieving excellent thermal conductivity and electromagnetic interference shielding efficiency

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Nano Research 2023年第8期16卷 11411-11421页

作者： Gui Yang Liangchun Zhou Mingjie Wang Tiantian Xiang Duo Pan Jingzhan Zhu Fengmei Su Youxin Ji Chuntai Liu Changyu Shen National Engineering Research Center for Advanced Polymer Processing Technology The Key Laboratory of Material Processing and Mold of Ministry of EducationCollege of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450002China

The rapid improvement in the running speed,transmission efficiency,and power density of miniaturized devices means that multifunctional flexible composites with excellent thermal management capability and high electromagnetic interference(EMI)shielding performance are urgently ***,inspired by the fibrous pathways of the human nervous system,a“core–sheath”fibers structured strategy was proposed to prepare thermoplastic polyurethane/polydopamine/carbon nanotube(TPU/PDA/CNT)composites film with thermal management capability and EMI shielding ***,TPU@PDA@CNT fibers with CNT shell were prepared by a facile polydopamine-assisted coating on electrospun TPU ***,TPU/PDA/CNT composites with three-dimensional(3D)fibrous CNT“tracks”are obtained by a hot-pressing process,where CNTs distributed on adjacent fibers are compactly *** fabricated TPU/PDA/CNT composites exhibit a high in-plane thermal conductivity(TC)of 9.6 W/(m·K)at low CNT loading of 7.6 wt.%.In addition,it also presents excellent mechanical properties and excellent EMI shielding effectiveness of 48.3 dB as well as multi-source driven thermal management ***,this study provides a simple yet scalable technique to prepare composites with advanced thermal management and EMI shielding performance to develop new-generation wireless communication technologies and portable intelligent electronic devices.

关键词： composites three-dimensional(3D)fibrous carbon nanotube(CNT)“tracks” in-plane thermal conductivity(TC) electromagnetic interference(EMI)shielding multi-source driven thermal management

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engineering Thermoelectric Performance of α-GeTe by Ferroelectric Distortion

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Energy & Environmental materials 2024年第2期7卷 171-179页

作者： Yuting Fan Chenghao Xie Jun Li Xiangyu Meng Jinchang Sun Jinsong Wu Xinfeng Tang Gangjian Tan State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China International School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

The rhombohedralα-GeTe can be approximated as a slightly distorted rock-salt structure along its[111]direction and possesses superb thermoelectric ***,the role of such a ferroelectric-like structural distortion on its transport properties remains ***,we performed a systematic study on the crystal structure and electronic band structure evolutions of Ge_(1-x)Sn_(x)Te alloys where the degree of ferroelectric distortion is continuously *** is revealed that the band gap is maximized while multiple valence bands are converged at x=0.6,where the ferroelectric distortion is the least but still *** undistorted,the band gap is considerably reduced,and the valence bands are largely separated ***,near the ferro-to-paraelectric phase transition Curie temperature,the lattice thermal conductivity reaches its minima because of significant lattice softening enabled by ferroelectric *** predict a peak ZT value of 2.6 at 673 K inα-GeTe by use of proper dopants which are powerful in suppressing the excess hole concentrations but meanwhile exert little influence on the ferroelectric distortion.

关键词： electronic band structures ferroelectric distortion lattice softening thermoelectric α-GeTe

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Homologous CoS2 interface with directed electron transfer and strong chloridion repulsion for efficient seawater oxidation

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Science China Chemistry 2025年第5期68卷 1869-1878页

作者： Yuan Tian Jiang-Bo Chen Jie Ying Ge Tian Yu-Xuan Xiao Yi Lu Si-Ming Wu Wei Geng Ling Shen Xiao-Yu Yang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing and School of Materials Science and Engineeringand Shenzhen Research Institute & Laoshan LaboratoryWuhan University of Technology School of Chemical Engineering and Technology Sun Yat-sen University National Energy Key Laboratory for New Hydrogen-Ammonia Energy Technologies Foshan Xianhu Laboratory

Seawater electrolysis is a highly promising method to produce high energy density hydrogen,especially in dry areas that have scarce freshwater ***,application of seawater electrolysis is confronted by two major problems associated with catalysts employed for the anodic oxygen evolution reaction（OER） including the competitive hypochlorite evolution reaction（HCER） and strong chloridion（Cl-） triggered *** studies aimed at overcoming these problems,a facile method has been developed to synthesize a homologous CoS2heterojunction as an OER *** to a difference in work functions at the interface and increased electron density,this material has directed electron transfer and strong chloridion repulsion properties,*** have shown that CoS2achieves low overpotentials of 289 and 322 mV at 10 mA cm-2current density in respective alkaline（1 M KOH） and alkaline simulated seawater ***,the outstanding stability of CoS2is reflected in a negligible decline in activity during promotion of the OER for 100 *** of density functional theory calculations reveal that the homologous CoS2heterojunction promotes directed electron transport for optimizing adsorption/desorption of reactive species and heightens the Cl-adsorption energy for strongly repulsing Cl-,phenomena that enhance OER performance in alkaline simulated seawater.

关键词： metal sulfide homologous heterojunction directed transfer chloride ion repulsion seawater electrolysis

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Effect of Rolling Temperature on the Mechanical Properties and Corrosion Behavior of Mg-Zn-Y-Nd Alloy Thin Sheets

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Acta Metallurgica Sinica(English Letters) 2024年第10期37卷 1721-1734页

作者： Zhibin Liu Guangya Zhu Wenkai Li Di Mei Peihua Du Yufeng Sun Shijie Zhu Shaokang Guan School of Materials Science and Engineering Zhengzhou UniversityZhengzhou450001China Henan Province Key Laboratory of Advanced Light Alloys Zhengzhou450002China Key Laboratory of Materials Processing and Mold(Ministry of Education) Zhengzhou450002China

There is a growing demand for degradable membranes with sufficient mechanical properties to guide tissue regeneration in dental *** the present work,a two-stage rolling process in which the first rolling stage(FRS)adopted a reduction rate of 30%for six passes at various temperatures,while the second rolling stage was rolling at 200℃for two passes,was employed to prepare a 150μm-grade Mg-2.0Zn-0.5Y-0.5Nd(ZE21B)Mg alloy sheets for guided tissue regeneration *** microstructure of the thin sheets was gradually refined with increasing rolling passes,and the thin sheets that were rolled at different FRS temperatures exhibit an ellipse *** thin sheets rolled at 350℃for FRS show low elongation due to premature fracture caused by the coarse second phase *** account of uniform and fine grains,the thin sheets rolled at 400℃for the FRS have proper mechanical properties:yield strength of 214.6±8.5 MPa,ultimate tensile strength(UTS)of 246.8±10.3 MPa and elongation to failure of 28.3±1.2%.When rolling at 450℃for FRS,proper ductility of the thin sheets has been acquired,followed by a decline in UTS since a bimodal structure with fine and coarse grain was *** tests demonstrated the FRS temperature had no significant effect on the corrosion behavior and corrosion rate of Mg alloy sheets after 7 days’immersion in artificial saliva *** research has great significance for the production of degradable Mg sheets for guided tissue regeneration membrane.

关键词： Mg alloy thin sheets Two-stage rolling Guided tissue regeneration membrane Artificial saliva Corrosion behavior

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Mg-Sc-Nd-xZn series alloys with medium strength and high plasticity

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Journal of Rare Earths 2024年第12期42卷 2362-2373,I0006页

作者： Fulong Xue Zhuangzhuang Feng Yubo Gao Di Mei Baolin Chang Jianfeng Wang Shijie Zhu Shaokang Guan School of Materials Science and Engineering Zhengzhou UniversityZhengzhou450001China Henan Province Key Laboratory of Advanced Light Alloys Zhengzhou450002China Key Laboratory of Materials Processing and Mold(Ministry of Education) Zhengzhou450002China

Different application scenarios put forward diverse requirements of mechanical properties for magnesium *** this study,the extruded Mg-Sc-Nd-Zn alloy series with high plasticity and medium strength was *** uniformly distributed Mg_(3)Nd(β_(1))phase,high-density twins,and the activated non-basal dislocation slips contribute to the high plasticity of Mg-Sc-Nd *** the addition of Zn element,the appearance of coarse ScZn phases,which prevents the activation of{1012}tensile twins,leads to an increase in strength but a simultaneous decrease in the plasticity of the extruded *** the Zn content in the Mg-Sc-Nd-xZn allows a series of alloys with various strengths and plasticity *** results obtained in this work are of great importance for developing a regulatable magnesium alloy series that aims at different application scenarios.

关键词： Magnesium alloy Tension twin Non-basal slip High plasticity Rare earths

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Exploring the effect of cooling rate on non-isothermal crystallization of copolymer polypropylene by fast scanning calorimetry

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China Foundry 2024年第4期21卷 379-386页

作者： Yang Liao Ye-yuan Hu Kosuke Ikeda Ryoji Okabe Rui-fen Wu Ryota Ozaki Qing-yan Xu Key Laboratory for Advanced Materials Processing Technology School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Composite Laboratory Research&Innovation Center Mitsubishi Heavy Industries Ltd.Nagasaki 8510392Japan

Polypropylene is commonly used as a binder for ceramic injection molding,and rapid cooling is often encountered during ***,the crystallization behavior of polypropylene shows a strong dependence on cooling rate due to its semi-crystalline ***,the influence of cooling rate on the quality of final product cannot be *** this study,the fast differential scanning calorimetry(FSC)test was performed to study the influence of cooling rate on the non-isothermal crystallization behavior and non-isothermal crystallization kinetics of a copolymer polypropylene(PP BC03B).The results show that the crystallization temperatures and crystallinity decrease as the cooling rate *** addition,two exothermic peaks occur when cooling rate ranges from 30 to 300 K·s^(-1),indicating the formation of another crystal ***,Ozawa and Mo equations were used to explore the non-isothermal crystallization kinetics,and it can be concluded that the Mo method is suitable for this study.

关键词： cooling rate crystallization temperature crystallinity non-isothermal crystallization kinetics FSC copolymer polypropylene

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