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Journal of Materiomics 2024年第2期10卷 423-430页

作者： Yiwen Liu Hulei Yu Hong Meng yanhui chu School of Materials Science and Engineering South China University of TechnologyGuangzhou510641China

Understanding the initial oxidation mechanism is critical for studying the oxidation resistance of high-entropy ***,related studies are ***,the initial oxidation mechanism of(Zr_(0.25)Ti_(0.25)Nb_(0.25)Ta_(0.25))B_(2)high-entropy diborides(HEB_(2)-1)is investigated by first-principles calculations at the atomic *** employing the two-region model method,the most stable surface of HEB_(2)-1 is determined to be(1120)*** dissociative adsorption process of the oxygen molecule on the HEB_(2)-1-(1120)surface is predicted to proceed spontaneously,where OeO bond breaks and each oxygen atom is chemisorbed on the most preferable hollow *** adsorption energy and the diffusion barrier of the oxygen atom on the(1120)surface of HEB_(2)-1 are in the vicinity of the average level of the cor-responding four individual *** addition,ab initio molecular dynamics simulations indicate a high initial oxidation resistance of HEB_(2)-1 at 1000 *** results are beneficial to further designing the high-entropy diborides with excellent oxidation resistance.

关键词： High-entropy diborides Oxidation First-principles calculations

Data-driven discovery of formation ability descriptors for high-entropy rare-earth monosilicates

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Journal of Materiomics 2024年第3期10卷 738-747页

作者： Hong Meng Peng Wei Zhongyu Tang Hulei Yu yanhui chu School of Materials Science and Engineering South China University of TechnologyGuangzhou510641China

Herein we establish formation ability descriptors of high-entropy rare-earth monosilicates(HEREMs)via the data-driven discovery based on the high-throughput solid-state reaction and machine learning(ML)***,adequate high-quality data are generated with 132 samples synthesized by the self-developed high-throughput solid-state reaction apparatuses,and 30 potential descriptors are considered in ML *** classifications are proposed to study the phase formation of HEREMs via the ML approach combined with the genetic algorithm:(Ⅰ)to distinguish pure HEREMs(X)from other phases and(Ⅱ)to categorize the detail phases of HEREMs(X2,X1,or X2+X1).Four formation ability descriptors(r_(Me),EF,d_(Eg),and d_(Z*))with a high validation accuracy(96.2%)are proposed as the optimal combination for Classification I,where a smaller r_(Me)is determined to have the most significant influence on the formation of *** ClassificationⅡ,a 100%validation accuracy is achieved by using only two formation ability descriptors(rion and d_(Z*)),where the rion is analyzed to be the dominant feature and a lower rion is beneficial to the formation of *** on our established formation ability descriptors,6,045 unreported multicomponent silicates are explored,and 3,478 new HEREMs with 2,700 X2-and 423 X1-HEREMs are predicted.

关键词： High-entropy rare-earth monosilicates Formation ability descriptors High-throughput experiments Machine learning

Enhanced oxidation resistance of high-entropy diborides by multicomponent synergistic effects

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Science China Materials 2024年第10期67卷 3392-3400页

作者： Zhongyu Tang Zihao Wen Lei Zhuang Hulei Yu yanhui chu School of Materials Science and Engineering South China University of TechnologyGuangzhou 510641China

Oxidation resistance is critical for high-entropy diborides(HEBs)to be used as thermal structural components under oxygen-containing high-temperature ***,we successfully realize the exploitation of(Zr,Ta,Cr,W)B2 HEBs with superior oxidation resistance by comprehensively screening their *** be specific,21 kinds of HEB-xTM(x=0–25 mol%,TM=Zr,Ta,Cr,and W)samples are fabricated via an ultrafast high-temperature sintering *** as-fabricated HEB-5Cr samples show the best oxidation resistance at 1673 K among all the *** oxidation investigations further confirm the as-fabricated HEB-5Cr samples possess superior oxidation resistance with the parabolic oxidation behavior across 1473–1773 *** superior oxidation resistance is believed to result from the multi-component synergistic ***,the Ta^(5+)and W^(4+)cations with high ionic field strengths can promote the formation of 4B–O–4B linkages between[BO4]tetrahedrons by charge balance,which can stabilize the threedimensional skeletal structure of B_(2)O_(3)glass and consequently result in an improved viscosity of the B_(2)O_(3)glassy *** addition,the ZrO_(2)and Cr_(2)O_(3)with high melting points can dissolve into the B_(2)O_(3)glass to increase its glass transition temperature,leading to an enhanced viscosity of the B_(2)O_(3)glassy layer.

关键词： high-entropy diborides composition screening oxidation resistance synergistic effects

(Gd_(1/7)Dy_(1/7)Ho_(1/7)Er_(1/7)Tm_(1/7)Yb_(1/7)Lu_(1/7))_(2)Si_(2)O_(7)高熵稀土双硅酸盐:一种极具应用潜力的环境障涂层材料

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Science China Materials 2024年第8期67卷 2694-2699页

作者：刘洋庄磊谢平波俞呼雷褚衍辉 School of Materials Science and Engineering South China University of TechnologyGuangzhou 510641China

作为一种潜在的环境障涂层材料,高熵稀土双硅酸盐的热物理化学性质至关重要.本文报道了一种新型(Gd_(1/7)Dy_(1/7)Ho_(1/7)Er_(1/7)Tm_(1/7)Yb_(1/7)Lu_(1/7))_(2)Si_(2)O_(7)高熵稀土双硅酸盐(7HERED),它兼具与SiC_(f)/SiC复合材料良好的热膨胀系数匹配性、超低的热导率(1273K时为1.5Wm^(-1)K^(-1))、高达1973K的高温稳定性以及在1673K下优异的耐水氧腐蚀性等优异的综合性能.这种优异的综合性能可归因于7HERED的高熵效应和晶格畸变效应.本文所开发的7HERED有望作为下一代环境障涂层材料.

关键词：晶格畸变热膨胀系数环境障涂层硅酸盐匹配性物理化学性质高熵高温稳定性

Molten salt synthesis, formation mechanism, and oxidation behavior of nanocrystalline HfB2 powders

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Journal of Advanced Ceramics 2020年第1期9卷 35-44页

作者： Da LIU Qiangang FU yanhui chu School of Materials Science and Engineering South China University of TechnologyGuangzhou 510641China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China

Nanocrystalline Hf B2 powders were successfully synthesized by molten salt synthesis technique at 1373 K using B and Hf O2 as precursors within KCl/Na Cl molten *** results showed that the as-synthesized powders exhibited an irregular polyhedral morphology with the average particle size of 155 nm and possessed a single-crystalline *** a fundamental aspect,we demonstrated the molten-salt assisted formation mechanism that the molten salts could accelerate the diffusion rate of the reactants and improve the chemical reaction rate of the reactants in the system to induce the synthesis of the high-purity nanocrystalline *** analysis showed that the oxidation of the as-synthesized Hf B2 powders at 773–1073 K in air was the weight gain process and the corresponding oxidation behavior followed parabolic kinetics governed by the diffusion of oxygen in the oxide layer.

关键词： ultra-high temperature ceramics powders molten salt synthesis oxidation behavior

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猴痘一例

中国麻风皮肤病杂志 2024年第6期40卷 383-384页

作者：孟玲玉初艳慧乔富宇魏孝侃北京市西城区疾病预防控制中心传染病预防与控制科北京100120

患者,男,29岁。阴茎疱疹伴疼痛4天。查体见生殖器及肛周疱疹,伴有瘙痒、疼痛,腹股沟处有肿大的淋巴结。辅助检查显示患者咽拭子、疱疹涂抹及血液样本猴痘病毒核酸均为阳性。患者发病3周前有男男高危性行为史。诊断:猴痘。患者转定点传... 详细信息

患者,男,29岁。阴茎疱疹伴疼痛4天。查体见生殖器及肛周疱疹,伴有瘙痒、疼痛,腹股沟处有肿大的淋巴结。辅助检查显示患者咽拭子、疱疹涂抹及血液样本猴痘病毒核酸均为阳性。患者发病3周前有男男高危性行为史。诊断:猴痘。患者转定点传染病医院治疗。

关键词：猴痘男男性行为宣教疫苗

Synthesis of the superfine high-entropy zirconate nanopowders by polymerized complex method

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Journal of Advanced Ceramics 2022年第1期11卷 136-144页

作者： Yangjie HAN Renwang YU Honghua LIU yanhui chu School of Materials Science and Engineering South China University of TechnologyGuangzhou 510641China

The high-purity and superfine high-entropy zirconate nanopowders,namely(Y_(0.25)La_(0.25)Sm_(0.25)Eu_(0.25))_(2)Zr_(2)O_(7)nanopowders,without agglomeration,were successfully synthesized via polymerized complex method at low temperatures for the first *** results showed that the crystallinity degree,lattice strain,and particle size of the as-synthesized powders were gradually enhanced with the increase of the synthesis temperature from 800 to 1300℃.The as-synthesized powders involved fluorite phase in the range of 800-1200℃while they underwent the phase evolution from fluorite to pyrochlore at 1300℃.It is worth mentioning that the as-synthesized powders at 900℃are of the highest quality among all the as-synthesized powders,which is due to the fact that they not only possess the particle size of 11 nm without agglomeration,but also show high purity and good compositional uniformity.

关键词： high-entropy oxides zirconates nanopowders polymerized complex method

Chrysanthemum-like high-entropy diboride nanoflowers: A new class of high-entropy nanomaterials

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Journal of Advanced Ceramics 2020年第3期9卷 339-348页

作者： Da LIU Honghua LIU Shanshan NING yanhui chu School of Materials Science and Engineering South China University of TechnologyGuangzhou 510641China

High-entropy nanomaterials have been arousing considerable interest in recent years due to their huge composition space,unique microstructure,and adjustable *** studies focused mainly on high-entropy nanoparticles,while other high-entropy nanomaterials were rarely ***,we reported a new class of high-entropy nanomaterials,namely(Tao2Nbo2Ti.2Wo.2Moo2)B2 high-entropy diboride(HEB-1)nanoflowers,for the first *** possibility of HEB-1 was first theoretically analyzed from two aspects of lattice size difference and chemical reaction *** then successfully synthesized HEB-1 nanoflowers by a facile molten salt synthesis method at 1423 *** as-synthesized HEB-1 nanoflowers showed an interesting chrysanthemum-like morphology assembled from numerous well-aligned nanorods with diameters of 20--30 nm and lengths of 100-200 ***,these nanorods possessed a single-crystalline hexagonal structure of metal diborides and highly compositional uniformity from nanoscale to *** addition,the formation of the as-synthesized HEB-I nanoflowers could be well interpreted by a classical surface-contolled crystal growth *** work not only enriches the categories of high-entropy nanomaterials but also opens up a new research field on high-entropy diboride nanomaterials.

关键词： high-entropy materials diborides nanomaterials molten salt synthesis

SiC Nanowires Toughed HfC Ablative Coating for C/C Composites

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Journal of Materials Science & Technology 2015年第1期31卷 70-76页

作者： Hejun Li Yongjie Wang Qiangang Fu yanhui chu State Key Laboratory of Solidification Processing Northwestern Polytechnical University

In order to improve ablation resistance of carbon/carbon(C/C) composites,SiC nanowires were prepared on C/C composites surface in prior through chemical vapor reaction before HfC *** nanowires grew randomly and had good combination with HfC *** nanowires toughed HfC coating had lower linear and mass ablation rates than original HfC *** surface was much flatter and exhibited smaller cracks in center *** ablation mechanism of HfC coating has been changed by SiC *** HfO2 fused layer was formed on the surface of the toughed HfC coating,which could provide efficient protection for C/C ***,SiC nanowires toughed HfC coating behaved in better ablation resistance.

关键词： Ablation performance Carbon/carbon composites Carb

Ultrafine-grained high-entropy zirconates with superior mechanical and thermal properties

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Journal of Materiomics 2023年第2期9卷 370-377页

作者： Mengdong Ma Yangjie Han Zhisheng Zhao Jing Feng yanhui chu School of Materials Science and Engineering South China University of TechnologyGuangzhou510641China Center for High Pressure Science(CHiPS) State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao066004China School of Materials Science and Engineering Kunming University of Science and TechnologyKunming650093China

Ultrafine-grained(Sm_(0.2)Gd_(0.2)Dy_(0.2)Er_(0.2)Yb_(0.2))_(2)Zr_(2)O_(7)high-entropy zirconates with single fluorite structure have been fabricated by high-pressure sintering of the self-synthesized nanopowders for the first *** as-sintered samples exhibit a good microstructure with a grain size of 220 nm and a relative density of 96.8%,which yield excellent comprehensive mechanical properties with a high Vickers hardness of 12.5 GPa and a high fracture toughness of 3.4 MPa·m1/*** addition,the as-sintered samples possess a good thermostability with the grain growth rate of 30 nm/h,and a low thermal conductivity of 1.57 W·m^(-1)·℃^(-1)at room *** superior mechanical and thermal properties are primarily attributed to the“high-entropy”and grain-refinement effects and good interface bonding.

关键词： High-entropy ceramics Zirconates Mechanical properties Thermal conductivity