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| 1 | Reprogramming of ovine adult fibroblasts to pluripotency via drug-inducible expression of defined factors显示文摘在 enucleated 鸡蛋的体的房间的 Reprogramming 做了多丽,绵羊,在 1996 的第一个成功地克隆的哺乳动物。然而,绵羊的机制体的房间 reprogramming 还没被探讨了。而且,绵羊胚胎的茎(ES ) 细胞仍然不是可得到的,它限制精确修改基因的绵羊的产生。在这研究,我们报导体的房间能是的那只绵羊直接 reprogrammed 到导致的 pluripotent 用定义因素(Oct4, Sox2, c-Myc, Klf4, Nanog, Lin28, SV40 大 T 和 hTERT ) 的茎(iPS ) 房间。我们的观察显示从绵羊的体的细胞比从另外的种,在 iPS,细胞被报导了的体的细胞对改编更困难。我们证明绵羊 iPS 房间表示 ES 房间标记,包括碱的磷酸酶, Oct4, Nanog, Sox2, Rex1,阶段特定的胚胎的 antigen-1, TRA-1-60, TRA-1-81 和 E-cadherin。绵羊 iPS 房间展出了正常 karyotypes 并且能在 vitro 并且在 teratomas 区分进所有三细菌层。我们的学习可以帮助在绵羊揭示体的房间 reprogramming 的机制并且提供一个平台为绵羊 ES 房间探索文化条件。而且,绵羊 iPS 房间可以直接被用来产生精确修改基因的绵羊。 | Lei Bao Lixiazi He Jijun Chen Zhao Wu Jing Liao Lmgdun Rao Jiangtao Ren Hui Li Hui Zhu Lei Qian Yijun Gu Huimin Dai Xun Xu Jinqiu Zhou Wen Wang Chun Cui Lei Xiao | 2011 | Cell Research2011，21，4： | 32 |
| 2 | High entropy defective fluorite structured rare-earth niobates and tantalates for thermal barrier applications显示文摘Rare-earth tantalates and niobates(REjTaO7 and REjNbO7)have been considered as promising candidate thermal barrier coating(TBC)materials in next generation gas-turbine engines due to their ultra-low thermal conductivity and better thermal stability than yttria-stabilized zirconia(YSZ).However,the low Vickers hardness and toughness are the main shortcomings of RE;TaO-and REjNbOr that limit their applications as TBC materials.To increase the hardness,high entropy(Yu3Ybu3Er/3)sTaOr,(Y13YbnErns)NbO,and(Sm1/6Eu1/6Y 1/6Yb1/6Lu1/6Er1/6)3(Nb1/2Ta1/2)O7 are designed and synthesized in this study.These high entropy ceramics exhibit high Vickers hardness(10.912.0 GPa),close thermal expansion coefficients to that of single-principal-component RE3TaO,and RE;NbO,(7.9×10^-6-10.8×10-6 C-1 at room temperature),good phase stability,and good chemical compatibility with thermally grown Al2O3,which make them promising for applications as candidate TBC materials. | Zifan ZHAO Heng CHEN Huimin XIANG Fu-Zhi DAI Xiaohui WANG Wei XU Kuang SUN Zhjjian PENG Yanchun ZHOU | 2020 | Journal of Advanced Ceramics2020，9，3： | 27 |
| 3 | High-entropy ceramics:Present status,challenges,and a look forward显示文摘High-entropy ceramics (HECs) are solid solutions of inorganic compounds with one or more Wyckoff sites shared by equal or near-equal atomic ratios of multi-principal elements.Although in the infant stage,the emerging of this new family of materials has brought new opportunities for material design and property tailoring.Distinct from metals,the diversity in crystal structure and electronic structure of ceramics provides huge space for properties tuning through band structure engineering and phonon engineering.Aside from strengthening,hardening,and low thermal conductivity that have already been found in high-entropy alloys,new properties like colossal dielectric constant,super ionic conductivity,severe anisotropic thermal expansion coefficient,strong electromagnetic wave absorption,etc.,have been discovered in HECs.As a response to the rapid development in this nascent field,this article gives a comprehensive review on the structure features,theoretical methods for stability and property prediction,processing routes,novel properties,and prospective applications of HECs.The challenges on processing,characterization,and property predictions are also emphasized.Finally,future directions for new material exploration,novel processing,fundamental understanding,in-depth characterization,and database assessments are given. | Huimin XIANG Yan XING Fu-zhi DAI Hongjie WANG Lei SU Lei MIAO Guojun ZHANG Yiguang WANG Xiwei QI Lei YAO Hailong WANG Biao ZHAO Jianqiang LI Yanchun ZHOU | 2021 | Journal of Advanced Ceramics2021，10，3： | 28 |
| 4 | (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2Zr2O7:A novel high-entropy ceramic with low thermal conductivity and sluggish grain growth rate显示文摘Fine grains and slow grain growth rate are beneficial to preventing the thermal stress-induced cracking and thermal conductivity increase of thermal barrier coatings.Inspired by the sluggish diffusion effect of high-entropy materials,a novel high-entropy(HE)rare-earth zirconate solid solution(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 was designed and successfully synthesized in this work.The as-synthesized(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 is phase-pure with homogeneous rare-earth element distribution.The thermal conductivity of as-synthesized(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 at room temperature is as low as 0.76 W m^-1 K^-1.Moreover,after being heated at 1500℃for 1-18 h,the average grain size of(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 only increases from 1.69μm to 3.92μm,while the average grain size of La2Zr2O7 increases from 1.96μm to 8.89μm.Low thermal conductivity and sluggish grain growth rate indicate that high-entropy(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2Zr2O7 is suitable for application as a thermal barrier coating material and it may possess good thermal stress-induced cracking resistance. | Zifan Zhao Huimin Xiang Fu-Zhi Dai Zhijian Peng Yanchun Zhou | 2019 | Journal of Materials Science & Technology2019，35，11： | 25 |
| 5 | High porosity and low thermal conductivity high entropy(Zr0.2Hf0.2Ti0.2Nb0.2Ta0.2C显示文摘Porous ultra-high temperature ceramics(UHTCs)are promising for ultrahigh-temperature thermal insulation applications.However,the main limitations for their applications are the high thermal conductivity and densification of porous structure at high temperatures.In order to overcome these obstacles,herein,porous high entropy(Zr(0.2)Hf(0.2)Ti(0.2)Nb(0.2)Ta(0.2))C was prepared by a simple method combing in-situ reaction and partial sintering.Porous high entropy(Zr(0.2)Hf(0.2)Ti(0.2)Nb(0.2)Ta(0.2))C possesses homogeneous microstructure with grain size in the range of 100–500 nm and pore size in the range of 0.2–1μm,which exhibits high porosity of 80.99%,high compressive strength of 3.45 MPa,low room temperature thermal conductivity of 0.39 W·m^-1K^-1,low thermal diffusivity of 0.74 mm^2·s^-1and good high temperature stability.The combination of these properties renders porous high entropy(Zr(0.2)Hf(0.2)Ti(0.2)Nb(0.2)Ta(0.2))Cpromising as light-weight ultrahigh temperature thermal insulation materials. | Heng Chen Huimin Xiang Fu-Zhi Dai Jiachen Liu Yiming Lei Jie Zhang Yanchun Zhou | 2019 | Journal of Materials Science & Technology2019，35，8： | 16 |
| 6 | Porous high entropy(Zr0.2Hf0.2Ti0.2Nb0.2Ta0.2)B2: A novel strategy towards making ultrahigh temperature ceramics thermal insulating显示文摘Transition metal diborides based ultrahigh temperature ceramics(UHTCs) are characterized by high melting point, high strength and hardness, and high electrical and thermal conductivity. The high thermal conductivity arises from both electronic and phonon contributions. Thus electronic and phonon contributions must be controlled simultaneously in reducing the thermal conductivity of transition metal diborides. In high entropy(HE) materials, both electrons and phonons are scattered such that the thermal conductivity can significantly be reduced, which opens a new window to design novel insulating materials. Inspired by the high entropy effect, porous HE(Zr0.2Hf0.2Ti0.2Nb0.2Ta0.2)B2 is designed in this work as a new thermal insulting ultrahigh temperature material and is synthesized by an in-situ thermal borocarbon reduction/partial sintering process. The porous HE(Zr0.2Hf0.2Ti0.2Nb0.2Ta0.2)B2 possesses high porosity of 75.67%, pore size of 0.3–1.2 μm, homogeneous microstructure with small grain size of 400–800 nm, which results in low room temperature thermal diffusivity and thermal conductivity of 0.74 mm2 s^-1 and 0.51 W m^-1K^-1, respectively. In addition, it exhibits high compressive strength of3.93 MPa. The combination of these properties indicates that exploring porous high entropy ceramics such as porous HE(Zr0.2Hf0.2Ti0.2Nb0.2Ta0.2)B2 is a novel strategy in making UHTCs thermal insulating. | Heng Chen Huimin Xiang Fu-Zhi Dai Jiachen Liu Yanchun Zhou | 2019 | Journal of Materials Science & Technology2019，35，10： | 15 |
| 7 | (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)PO4: A high-entropy rare-earth phosphate monazite ceramic with low thermal conductivity and good compatibility with Al2O3显示文摘Low thermal conductivity, matched thermal expansion coefficient and good compatibility are general requirements for the environmental/thermal barrier coatings(EBCs/TBCs) and interphases for Al2O3 f/Al2O3 composites. In this work, a novel high-entropy(HE) rare-earth phosphate monazite ceramic (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)PO4 is designed and successfully synthesized. This new type of HE rare-earth phosphate monazite exhibits good chemical compatibility with Al2O3, without reaction with Al2O3 as high as 1600℃ in air. Moreover, the thermal expansion coefficient(TEC) of HE (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)PO4(8.9 × 10^-6/℃ at 300–1000℃) is close to that of Al2O3. The thermal conductivity of HE (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)PO4 at room temperature is as low as 2.08 W·m^-1·K^-1, which is about 42% lower than that of La PO4. Good chemical compatibility, close TEC to that of Al2O3, and low thermal conductivity indicate that HE (La0.2Ce0.2Nd0.2Sm0.2Eu0.2)PO4 is suitable as a candidate EBC/TBC material and an interphase for Al2O3 f/Al2O3 composites. | Zifan Zhao Heng Chen Huimin Xiang Fu-Zhi Dai Xiaohui Wang Zhijian Peng Yanchun Zhou | 2019 | Journal of Materials Science & Technology2019，35，12： | 15 |
| 8 | One-step synthesis and electromagnetic absorption properties of high entropy rare earth hexaborides(HE REB6)and high entropy rare earth hexaborides/borates(HE REB6/HE REB03)composite powders显示文摘Considering the emergence of severe electromagnetic interference problems,it is vital to develop electromagnetic(EM)wave absorbing materials with high dielectric,magnetic loss and optimized impedance matching.However,realizing the synergistic dielectric and magnetic losses in a single phase material is still a challenge.Herein,high entropy(HE)rare earth hexaborides(REB6)powders with coupling of dielectric and magnetic losses were designed and successfully synthesized through a facial one-step boron carbide reduction method,and the effects of high entropy borates intermedia phases on the EM wave absorption properties were investigated.Five HE REB6 ceramics including(Ce0.2Y0.2Sm0.2Er0.2Yb0.2)B6,(Ce0.2Hu0.2Sm0.2Er0.2Yb0.2)B6,(Ce0.2Y0.2Eu0.2Er0.2Yb0.2)B6,(Ce0.2Ya2Sm0.2Eu0.2Yb0.2)B6,and(Nd0.2Y0.2Sm0.2Eu0.2Yb0.2)B6 possess CsCl-type cubic crystal structure,and their theoretical densities range from 4.84 to 5.25 g/cm^(3).(Ce02Y0.2Sm0.2Er0.2Yb02)B6 powders with the average particle size of 1.86 jim were found to possess the best EM wave absorption properties among these hexaborides.The RLmin value of(Ce0.2Y0.2Sm0.2Er0.2Yb0.2)B6 reaches-33.4 dB at 11.5 GHz at thickness of 2 mm;meanwhile,the optimized effective absorption bandwidth(EAB)is 3.9 GHz from 13.6 to 17.5 GHz with a thickness of 1.5 mm.The introduction of HE REB03(RE=Ce,Y,Sm,Eu,Er,Yb)as intermediate phase will give rise to the mismatching impedance,which will further lead to the reduction of reflection loss.Intriguingly,the HEREB6/HEREB03 still possess wide effective absorption bandwidth of 4.1 GHz with the relative low thickness of 1.7 mm.Considering the better stability,low density,and good EM wave absorption properties,HE REB6 ceramics are promising as a new type of EM wave absorbing materials. | Weiming ZHANG Biao ZHAO Huimin XIANG Fu-Zhi DAI Shijiang WU Yanchun ZHOU | 2021 | Journal of Advanced Ceramics2021，10，1： | 15 |
| 9 | High entropy(Yb0.25Y0.25Lu0.25Er0.25)2SiO5 with strong anisotropy in thermal expansion显示文摘A novel high entropy(HE) rare earth monosilicate(Yb0.25Y0.25Lu0.25Er0.252 SiO5 was synthesized by solid-state reaction method.X-ray diffraction and scanning electron microscopy analysis indicate that a single solid solution is formed with homogeneous distribution of rare-earth elements.HE(Yb0.25Y0.25Lu0.255 Er0.252 SiO5 exhibits excellent phase stability and anisotropy in thermal expansion.The coefficients of thermal expansion(CTEs) in three crystallographic directions are:αa=(2.57±0.07)×10^-6 K^-1,αb=(8.07±0.13)×10^-6 K^-1,αc=(9.98±0.10)×10^-6 K^-1.The strong anisotropy in thermal expansion is favorable in minimizing the coating/substrate mismatch if preferred orientation of HE(Yb0.25Y0.25Lu0.25Er0.252 SiO5 is controlled on either metal or ceramic substrate. | Heng Chen Huimin Xiang Fu-Zhi Dai Jiachen Liu Yanchun Zhou | 2020 | Journal of Materials Science & Technology2020，36，1： | 14 |
| 10 | High entropy(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12:A novel high temperature stable thermal barrier material显示文摘Ytterbium aluminum garnet(Yb3Al5O12)is considered as a promising thermal barrier material.However,the main limitations of Yb3Al5O12 for thermal barrier applications are relative low thermal expansion coefficient and high thermal conductivity.In order to overcome these obstacles,herein,a new high entropy(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 ceramic was designed,and then powders and bulk were prepared through solid-state reaction method and spark plasma sintering(SPS),respectively.The thermal expansion coefficient of HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 is(8.54±0.29)×10^-6 K^-1 at 673 K–1273 K,which is about 9%higher than that of Yb3Al5O12.The thermal conductivity of HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 ceramic is 3.81 W·m^-1 K^-1 at 300 K,which is about 18%lower than that of Yb3Al5O12.Moreover,there is no reaction between HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 and thermally grown(TG)Al2O3 even at 1600℃.After annealing at 1590℃for 18 h,the average grain size of HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 increases only from 1.56μm to 2.27μm.Close thermal expansion coefficient to TG Al2O3,low thermal conductivity,good phase stability,excellent chemical compatibility with TG Al2O3 and slow grain growth rate make HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 promising for thermal barrier applications. | Heng Chen Zifan Zhao Huimin Xiang Fu-Zhi Dai Wei Xu Kuang Sun Jiachen Liu Yanchun Zhou | 2020 | Journal of Materials Science & Technology2020，47，13： | 14 |
| 11 | Electromagnetic wave absorbing properties of TMCs(TM=Ti,Zr,Hf,Nb and Ta)and high entropy(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C显示文摘Electromagnetic wave(EMW)absorbing materials play a vital role in modern communication and information processing technologies to inhibit information leakage and prevent possible damages to environment and human bodies.Currently,most of EMW absorbing materials are either composites of two or more phases or in the form of nanosheets,nanowires or nanofibers in order to enhance the EMW absorption performance through dielectric loss,magnetic loss and dielectric/magnetic loss coupling.However,the combination of complex shapes/multi phases and nanosizes may compound the difficulties of materials processing,composition and interfaces control as well as performance maintenance during service.Thus,searching for single phase materials with good stability and superior EMW absorbing properties is appealing.To achieve this goal,the EMW absorbing properties of transition metal carbides TMCs(TM=Ti,Zr,Hf,Nb and Ta)and high entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C which belong to ultrahigh temperature ceramics,were investigated in this work.Due to the good electrical conductivity and splitting of d orbitals into lower energy t2glevel and higher energy eglevel in TMC6octahedral arrangement,TMCs(TM=Ti,Zr,Hf,Nb and Ta)exhibit good EMW absorbing properties.Especially,Hf C and Ta C exhibit superior EMW absorbing properties.The minimum reflection loss(RLmin)value of Hf C is-55.8 d B at 6.0 GHz with the thickness of 3.8 mm and the effective absorption bandwidth(E_(AB))is 6.0 GHz from 12.0 to 18.0 GHz at thickness of 1.9 mm;the RL_(minvalue)of Ta C reaches-41.1 d B at 16.2 GHz with a thickness of 2.0 mm and the EABis 6.1 GHz with a thickness of 2.2 mm.Intriguingly,the electromagnetic parameters,i.e.,complex permittivity and permeability are tunable by forming single phase solid solution or high entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C.The R_(Lminvalue)of high entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C is-38.5 d B at 9.5 GHz with the thickness of 1.9 mm,and the EABis 2.3 GHz(from 11.3 to 13.6 GHz)at thickness of 1.5 mm.The significance of this work is that it opens a new window to design single phase high performance EMW absorbing materials by dielectric/magnetic loss coupling through tuning the conductivity and crystal field splitting energy of d orbitals of transition metals in carbides,nitrides and possibly borides. | Yanchun Zhou Biao Zhao Heng Chen Huimin Xiang Fu-Zi Dai Shijiang Wu Wei Xu | 2021 | Journal of Materials Science & Technology2021，，15： | 13 |
| 12 | Theoretical prediction on thermal and mechanical properties of high entropy(Zr(0.2)Hf(0.2)Ti(0.2)Nb(0.2)Ta(0.2))C by deep learning potential显示文摘High entropy materials(HEMs, e.g. high entropy alloys, high entropy ceramics) have gained increasing interests due to the possibility that they can provide challenge properties unattainable by traditional materials. Though a large number of HEMs have emerged, there is still in lack of theoretical predictions and simulations on HEMs, which is probably caused by the chemical complexity of HEMs. In this work,we demonstrate that the machine learning potentials developed in recent years can overcome the complexity of HEMs, and serve as powerful theoretical tools to simulate HEMs. A deep learning potential(DLP) for high entropy(Zr(0.2) Hf(0.2) Ti(0.2) Nb(0.2) Ta(0.2))C is fitted with the prediction error in energy and force being 9.4 me V/atom and 217 me V/?, respectively. The reliability and generality of the DLP are affirmed,since it can accurately predict lattice parameters and elastic constants of mono-phase carbides TMC(TM = Ti, Zr, Hf, Nb and Ta). Lattice constants(increase from 4.5707 ? to 4.6727 ?), thermal expansion coefficients(increase from 7.85×10-6 K^(-1) to 10.58×10-6 K^(-1)), phonon thermal conductivities(decrease from 2.02 W·m-1·K^(-1) to 0.95 W·m-1·K^(-1)), and elastic properties of high entropy(Zr(0.2) Hf(0.2) Ti(0.2) Nb(0.2) Ta(0.2))C in temperature ranging from 0°C to 2400°C are predicted by molecular dynamics simulations. The predicted room temperature properties agree well with experimental measurements, indicating the high accuracy of the DLP. With introducing of machine learning potentials, many problems that are intractable by traditional methods can be handled now. It is hopeful that deep insight into HEMs can be obtained in the future by such powerful methods. | Fu-Zhi Dai Bo Wen Yinjie Sun Huimin Xiang Yanchun Zhou | 2020 | Journal of Materials Science & Technology2020，36，8： | 12 |
| 13 | High-entropy(Nd_(0.2)Sm_(0.2)Eu_(0.2)Y_(0.2)Yb_(0.2))_(4)Al_(2)O_(9) with good high temperature stability,low thermal conductivity,and anisotropic thermal expansivity显示文摘The critical requirements for the environmental barrier coating(EBC)materials of silicon-based ceramic matrix composites(CMCs)include good tolerance to harsh environments,thermal expansion matches with the interlayer mullite,good high-temperature phase stability,and low thermal conductivity.Cuspidine-structured rare-earth aluminates RE_(4)Al_(2)O_(9) have been considered as candidates of EBCs for their superior mechanical and thermal properties,but the phase transition at high temperatures is a notable drawback of these materials.To suppress the phase transition and improve the phase stability,a novel cuspidine-structured rare-earth aluminate solid solution(Nd_(0.2)Sm_(0.2)Eu_(0.2)Y_(0.2)Yb_(0.2))_(4)Al_(2)O_(9) was designed and successfully synthesized inspired by entropy stabilization effect of high-entropy ceramics(HECs).The as-synthesized HE(Nd_(0.2)Sm_(0.2)Eu_(0.2)Y_(0.2)Yb_(0.2))_(4)Al_(2)O_(9) exhibits a close thermal expansion coefficient(6.96×10^(-6) K^(-1) at 300-1473 K)to that of mullite,good phase stability from 300 to 1473 K,and low thermal conductivity(1.50 W·m^(-1)·K^(-1) at room temperature).In addition,strong anisotropic thermal expansion has been observed compared to Y_(4)Al_(2)O_(9) and Yb_(4)Al_(2)O_(9).The mechanism for low thermal conductivity is attributed to the lattice distortion and mass difference of the constituent atoms,and the anisotropic thermal expansion is due to the anisotropic chemical bonding enhanced by the large size rare-earth cations. | Zifan ZHAO Huimin XIANG Heng CHEN Fu-Zhi DAI Xiaohui WANG Zhijian PENG Yanchun ZHOU | 2020 | Journal of Advanced Ceramics2020，9，5： | 12 |
| 14 | (TiZrHf)P2O7: An equimolar multicomponent or high entropy ceramic with good thermal stability and low thermal conductivity显示文摘Zr P2O7 is a promising material for high temperature insulating applications. However, decomposition above 1400℃ is the bottleneck that limiting its application at high temperatures. To improve the thermal stability, a novel multicomponent equimolar solid solution(Ti Zr Hf)P2O7 was designed and successfully synthesized in this work inspired by high-entropy ceramic(HEC) concept. The as-synthesized(Ti Zr Hf)P2O7 exhibits good thermal stability, which is not decomposed after heating at 1550℃ for 3 h. It also shows lower thermal conductivity(0.78 W m^-1 K^-1) compared to the constituting metal pyrophosphates Ti P2O7, Zr P2O7 and Hf P2O7. The combination of high thermal stability and low thermal conductivity renders(Ti Zr Hf)P2O7 promising for high temperature thermal insulating applications. | Zifan Zhao Huimin Xiang Fu-Zhi Dai Zhijian Peng Yanchun Zhou | 2019 | Journal of Materials Science & Technology2019，35，10： | 12 |
| 15 | Achieving strong microwave absorption capability and wide absorption bandwidth through a combination of high entropy rare earth silicide carbides/rare earth oxides显示文摘Developing electromagnetic(EM) wave absorbing materials with low reflection coefficient and optimal operating frequency band is urgently needed on account of the increasingly serious EM pollution. However, the applications of common EM absorbing materials are encumbered by poor high-temperature stability, poor oxidation resistance, narrow absorption bandwidth or high density. Herein, the strong EM absorption capability and wide efficient absorption bandwidth of high entropy ceramics are reported for the first time, which are designed by a combination of the novel high entropy(HE) rare earth silicide carbides/rare earth oxides(RE3 Si2 C2/RE2 O3). Three HE powders, i.e., HERSC-1(HE(Tm0.2 Y0.2 Dy0.2 Gd0.2 Tb0.2)3 Si2 C2),HERSC-2 HE(Tm0.2 Y0.2 Dy0.2 Gd0.2 Tb0.2)3 Si2 C2/HE(Tm0.2 Y0.2 Dy0.2 Gd0.2 Tb0.2)2 O3) and HERSC-3(HE(Tm0.2 Y0.2 Dy0.2 Gd0.2 Tb0.2)3 Si2 C2/HE(Tm0.2 Y0.2 Dy0.2 Gd0.2 Tb0.2)2 O3), are synthesized. Although HERSC-1 exhibits a limited absorption effect(the minimum reflection loss(RLmin) is-11.6 d B at 3.4 mm) and a relatively narrow effective absorption bandwidth(EAB) of 1.7 GHz, the optimal absorption RLminvalue and EAB of HERSC-2 and HERSC-3 are-40.7 d B(at 2.9 mm), 3.4 GHz and-50.9 d B(at 2.0 mm), 4.5 GHz,respectively, demonstrating strong microwave absorption capability and wide absorption bandwidth.Considering the better stability, low density and strong EM absorption effect, HE ceramics are promising as a new type of EM absorbing materials. | Heng Chen Biao Zhao Zifan Zhao Huimin Xiang Fu-Zhi Dai Jiachen Liu Yanchun Zhou | 2020 | Journal of Materials Science & Technology2020，47，12： | 12 |
| 16 | Preparation and properties of CMAS resistant bixbyite structured high-entropy oxides RE_(2)O_(3)(RE=Sm,Eu,Er,Lu,Y,and Yb):Promising environmental barrier coating materials for Al_(2)O_(3)f/Al_(2)O_(3) composites显示文摘Y_(2)O_(3) is regarded as one of the potential environmental barrier coating(EBC)materials for Al_(2)O_(3)f/Al_(2)O_(3)ceramic matrix composites owing to its high melting point and close thermal expansion coefficient to Al_(2)O_(3).However,the relatively high thermal conductivity and unsatisfactory calcium-magnesium-aluminosilicate(CMAS)resistance are the main obstacles for the practical application of Y_(2)O_(3).In order to reduce the thermal conductivity and increase the CMAS resistance,four cubic bixbyite structured high-entropy oxides RE_(2)O_(3),including(Eu_(0.2)Er_(0.2)Lu_(0.2)Y_(0.2)Yb_(0.2))2O_(3),(Sm_(0.2)Er_(0.2)Lu_(0.2)Y_(0.2)Yb_(0.2))2O_(3),(Sm_(0.2)Eu_(0.2)Er_(0.2)Y_(0.2)Yb_(0.2))2O_(3),and(Sm_(0.2)Eu_(0.2)Lu_(0.2)Y_(0.2)Yb_(0.2))2O_(3)were designed and synthesized,among which(Eu_(0.2)Er_(0.2)Lu_(0.2)Y_(0.2)Yb_(0.2))2O_(3)and(Sm_(0.2)Er_(0.2)Lu_(0.2)Y_(0.2)Yb_(0.2))2O_(3)bulks were prepared by spark plasma sintering(SPS)to investigate their mechanical and thermal properties as well as CMAS resistance.The mechanical properties of(Eu_(0.2)Er_(0.2)Lu_(0.2)Y_(0.2)Yb_(0.2))2O_(3)and(Sm_(0.2)Er_(0.2)Lu_(0.2)Y_(0.2)Yb_(0.2))2O_(3) are close to those of Y_(2)O_(3) but become more brittle than Y_(2)O_(3).The thermal conductivities of(Eu_(0.2)Er_(0.2)Lu_(0.2)Y_(0.2)Yb_(0.2))2O_(3) and(Sm_(0.2)Er_(0.2)Lu_(0.2)Y_(0.2)Yb02)2O_(3)(5.1 and 4.6 W·m^(-1)·K^(-1))are only 23.8%and 21.5%respectively of that of Y_(2)O_(3)(21.4 W·m^(-1)·K^(-1)),while their thermal expansion coefficients are close to those of Y_(2)O_(3) and A12O_(3).Most importantly,HE RE_(2)O_(3) ceramics exhibit good CMAS resistance.After being attacked by CMAS at 1350℃for 4 h,the HE RE_(2)O_(3) ceramics maintain their original morphologies without forming pores or cracks,making them promising as EBC materials for Al_(2)O_(3)f/Al_(2)O_(3) composites. | Yanan SUN Huimin XIANG Fu-Zhi DAI Xiaohui WANG Yan XING Xiaojun ZHAO Yanchun ZHOU | 2021 | Journal of Advanced Ceramics2021，10，3： | 10 |
| 17 | High-entropy(Y0.2Nd0.2Sm0.2Eu0.2Er0.2)AlO3:A promising thermal/environmental barrier material for oxide/oxide composites显示文摘Yttrium aluminum perovskite(YAl O3)is a promising candidate material for environmental barrier coatings(EBCs)to protect Al2 O3 f/Al2 O3 ceramic matrix composites(CMCs)from the corrosion of high-temperature water vapor in combustion environments.Nevertheless,the relatively high thermal conductivity is a notable drawback of YAl O3 for environmental barrier coating application.Herein,in order to make REAl O3 more thermal insulating,a novel high-entropy rare-earth aluminate ceramic(Y0.2Nd0.2Sm0.2Eu0.2Er0.2)AlO3 was designed and synthesized.The as-prepared(Y0.2Nd0.2Sm0.2Eu0.2Er0.2)AlO3 ceramic possesses close thermal expansion coefficient(9.02×10-6/oC measured from room temperature to 1200℃)to that of Al2 O3.The thermal conductivity of(Y0.2Nd0.2Sm0.2Eu0.2Er0.2)AlO3 at room temperature is 4.1 W·m-1K-1,which is almost one third of the value of YAl O3.Furthermore,to effectively prevent the penetration of water vapor from possible pores/cracks of coating layer,which are often observed in T/EBCs,a tri-layer EBC system REAl O3/RE3 Al5 O12/(Al2 O3 f/Al2 O3 CMCs)is designed.Close thermal expansion coefficient to Al2 O3 and low thermal conductivity of(Y0.2Nd0.2Sm0.2Eu0.2Er0.2)AlO3,as well as the formation of dense garnet layer at(Y0.2Nd0.2Sm0.2Eu0.2Er0.2)AlO3/Al2 O3 interface,indicate that this new type of high-entropy ceramic is suitable as a candidate environmental barrier coating material for Al2 O3 f/Al2 O3 CMCs. | Zifan Zhao Heng Chen Huimin Xiang Fu-Zhi Dai Xiaohui Wang Wei Xu Kuang Sun Zhijian Peng Yanchun Zhou | 2020 | Journal of Materials Science & Technology2020，47，12： | 9 |
| 18 | High entropy rare earth hexaborides/tetraborides(HE REB_(6)/HE REB_(4)) composite powders with enhanced electromagnetic wave absorption performance显示文摘The increasing electromagnetic hazards including electromagnetic interference and electromagnetic pollution,which were stemmed from massive usage of electromagnetic technology,have triggered widespread concerns.To cope with this challenge,electromagnetic wave absorbing materials with high performance are greatly needed.Composite construction has been widely applied in electromagnetic(EM)wave absorbing materials to achieve high permittivity,high permeability and impedance matching.However,high-temperature stability,oxidation and corrosion resistance are still unignorable issues.Herein,high entropy hexaborides/tetraborides(HE REB_(6)/HE REB_(4))composites with synergistic dielectric and magnetic losses were designed and successfully synthesized through a one-step boron carbide reduction method.The five as-prepared(Y_(0.2) Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2))B_(6)/(Y_(0.2) Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2))B_(4),(Y_(0.2) Nd_(0.2) Sm_(0.2) Er_(0.2) Yb_(0.2))B_(6)/(Y_(0.2) Nd_(0.2) Sm_(0.2) Er_(0.2) Yb_(0.2))B_(4),(Y_(0.2) Nd_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(6)/(Y_(0.2) Nd_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(4),(Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(6)/(Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(4) and(Y_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(6)/(Y_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(4) contain two phases of HE REB_(6) and HE REB_(4).Among them(Y_(0.2) Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2))B_(6)/(Y_(0.2) Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2))B_(4)(HE REB_(6)/HE REB_(4)-1)and(Y_(0.2) Nd_(0.2) Sm_(0.2) Er_(0.2) Yb_(0.2))B_(6)/(Y_(0.2) Nd_(0.2) Sm_(0.2) Er_(0.2) Yb_(0.2))B_(4)(HE REB_(6)/HE REB_(4)-2)exhibit excellent EM wave absorption properties.The optimal minimum reflection loss(RL_(m in))and effective absorption bandwidth(E_(AB))of HE REB_(6)/HE REB_(4)-1 and HE REB_(6)/HE REB_(4)-2 are–53.3 dB(at 1.7 mm),4.2 GHz(at 1.5 mm)and–43.5 dB(1.3 mm),4.2 GHz(1.5 mm),respectively.The combination of conducting HE REB_(4) with magnetism into HE REB_(6) as a second phase enhances dielectric and magnetic losses,which lead to enhanced EM wave absorption performance.Considering superior high-temperature stability,oxidation and corrosion resistance of HE REB_(6) and HE REB_(4),HE REB_(6)/HE REB_(4) composite ceramics are promising as a new type of high-performance EM wave absorbing materials. | Weiming Zhang Biao Zhao Na Ni Huimin Xiang Fu-Zhi Dai Shijiang Wu Yanchun Zhou | 2021 | Journal of Materials Science & Technology2021，，28： | 9 |
| 19 | Adsorption of rare earth ions using carbonized polydopamine nano carbon shells显示文摘Herein we reported the structure effects of carbon nano-shells prepared by the carbonization of polydopamine for the adsorption of rare earth elements(REEs) for the first time. Solid carbon spheres, 60 nm carbon shells and 500 nm carbon shells were prepared and evaluated for adsorption and desorption of REEs. The adsorption performance of carbon nano-shells for REEs was far superior to the solid carbon spheres. In addition, the effect of acidity on the adsorption and desorption properties was discussed. The good adsorption performance of the carbon nano-shells could be attributed to their pore structure, specific surface area, and the presence of both amine and carbonyl groups from the grafted dopamine. | 孙晓琦 LUO Huimin Shannon M.Mahurin LIU Rui HOU Xisen DAI Sheng | 2016 | Journal of Rare Earths2016，34，1： | 6 |
| 20 | Temperature Dependent Thermal and Elastic Properties of High Entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2):Molecular Dynamics Simulation by Deep Learning Potential显示文摘High entropy diborides are new categories of ultra-high temperature ceramics,which are believed promising candidates for applications in hypersonic vehicles.However,knowledge on high temperature thermal and mechanical properties of high entropy diborides is still lacking unit now.In this work,variations of thermal and elastic properties of high entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2) with respect to temperature were predicted by molecular dynamics simulations.Firstly,a deep learning potential for Ti-Zr-Hf-Nb-Ta-B diboride system was fitted with its prediction error in energy and force respectively being 9.2 meV/atom and 208 meV/A,in comparison with first-principles calculations.Then,temperature dependent lattice constants,anisotropic thermal expansions,anisotropic phonon thermal conductivities,and elastic properties of high entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2) from 0℃to 2400℃were evaluated,where the predicted room temperature values agree well with experimental measurements.In addition,intrinsic lattice distortions of(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2) were analyzed by displacements of atoms from their ideal positions,which are in an order of 10^(-3) A and one order of magnitude smaller than those in(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C.It indicates that lattice distortions in(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2) is not so severe as expected.With the new paradigm of machine learning potential,deep insight into high entropy materials can be achieved in the future,since the chemical and structural complexly in high entropy materials can be well handled by machine learning potential. | Fu-Zhi Dai Yinjie Sun Bo Wen Huimin Xiang Yanchun Zhou | 2021 | Journal of Materials Science & Technology2021，，13： | 6 |
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