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Intercalation of hafnium oxide between epitaxially-grown monolayer graphene and Ir(111)substrate

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中国物理B:英文版 2023年第9期32卷 506-509页

作者：表奕路红亮彭浩宋志朋郭辉林晓 University of Chinese Academy of Sciences and Institute of Physics Chinese Academy of SciencesBeijing 100190China

Intercalation of insulating materials between epitaxial graphene and the metal substrates is highly demanded to restore the intrinsic properties of graphene,and thus essential for the graphene-based devices.Here we demonstrate a successful solution for the intercalation of hafnium oxide into the interface between full-layer graphene and Ir(111)substrate.We first intercalate hafnium atoms beneath the epitaxial graphene.The intercalation of the hafnium atoms leads to the variation of the graphene moire superstructure periodicity,which is characterized by low-energy electron diffraction(LEED)and lowtemperature scanning tunneling microscopy(LT-STM).Subsequently,we introduce oxygen into the interface,resulting in oxidization of the intercalated hafnium.STM and Raman's characterizations reveal that the intercalated hafnium oxide layer could effectively decouple the graphene from the metallic substrate,while the graphene maintains its high quality.Our work suggests a high-k dielectric layer has been successfully intercalated between high-quality epitaxial graphene and metal substrate,providing a platform for applications of large-scale,high-quality graphene for electronic devices.

关键词： epitaxial graphene hafnium intercalation oxidization

High-pressure elastic anisotropy and superconductivity of hafnium:A first-principles calculation

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Chinese Physics B 2021年第5期30卷 547-557页

作者：张成斌李卫东张平王保田 Institute of Theoretical Physics and Department of Physics and Collaborative Innovation Center of Extreme OpticsShanxi UniversityTaiyuan 030006China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China LCP Institute of Applied Physics and Computational MathematicsBeijing 100088China

The elastic anisotropy and superconductivity upon hydrostatic compression ofα,ω,and β Hf are investigated using first-principle methods.The results of elastic anisotropies show that they increase with increasing pressure for α and ω phases,while decrease upon compression forβphase.The calculated superconducting transition temperatures are in excellent agreement with experiments.Electron-phonon coupling constants(λ)are increasing with pressure for α and ω phases,while decreasing for β phase.For β phase,the large values ofλare mainly due to the obvious TA1 soft mode.Under further compression,the TA1 soft vibrational mode will disappear gradually.

关键词： first-principles elastic anisotropy superconductivity hafnium

Intensification of zirconium and hafnium separation through the hollow fiber renewal liquid membrane technique using synergistic mixture of TBP and Cyanex-272 as extractant

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Chinese Journal of Chemical Engineering 2019年第8期27卷 1817-1827页

作者： A.Yadollahi M.Torab-Mostaedi K.Saberyan A.Charkhi F.Zahakifar Materials and Nuclear Fuel Research School Nuclear Science and Technology Research Institute

The novel synergistic mixture of TBP and Cyanex-272 is used as the extractant in the hollow fiber renewal liquid membrane(HFRLM) technique for Zr/Hf separation.The effects of the chemical and operational parameters such as HNO3 concentration in the donor phase,NH4 F concentration in the acceptor phase,Cyanex-272 and TBP concentration in the liquid membrane phase,the lumen and shell side flow rates,and aqueous/organic volume ratio on the mass transfer and separation performance of HFRLM method were investigated.The obtained results reveal the intensification potential of proposed HFRLM technique for selective extraction of Zr over Hf with separation factor higher than 100.The HFRLM method provides two times higher mass transfer flux in comparison with hollow fiber supported liquid membrane(HFSLM).Also,the HFRLM method shows satisfactory stability for 700 min of continuous operation.The Zr ion transport through the LM phase follows the coupled co-transport mechanism and the diffusion in the renewal layer is recognized as the rate-controlling step in the HFRLM process.Moreover,the Zr mass transfer coefficient and molar flux in the HFRLM method are calculated in the range of 1×10^-8 to 8.4×10^-7 m·s^-1 and 4.9×10^-6 to 20.1×10^-6 mol·m^-2·s^-1,respectively.

关键词： Zirconium hafnium Synergistic separation Hollow fiber renewal liquid membrane (HFRLM)

First-Principles Study of the Influence of Lattice Misfit on the Behavior and the Ductility Effect of hafnium in Ni-Ni3AI System

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Acta Metallurgica Sinica(English Letters) 2014年第1期27卷 87-94页

作者： Y. Wu J. Guo W. Zhang X. Ma Q. Zhang J. Hou R. Huang X. Liu Institute of Molecular Engineering and Applied Chemistry Anhui University of Technology Ma'anshan 243002 China Shenyang National Laboratory for Materials Science Instituteof Metal Research Chinese Academy of SciencesShenyang 110016 China College of Physics Science and Technology Shenyang NormalUniversity Huanghe Street 253 Shengyang 110034 China School of Materials Science and Engineering Anhui Universityof Technology Ma'anshan 243002 China

Two Ni/Ni3Al-interface-contained cluster models with/without lattice misfit are studied by first-principles method to clarify the debates about the segregation behaviors of hafnium （Hf） and explore the influence of lattice misfit on the ductility effect of Hr. It is found that though Hf prefers to substitute A1 rather than Ni in Ni3A1 phase within most of the investigated misfit range, its stronger preferring to Ni phase than NiaA1 phase makes it impossible to go into Ni3A1 phase to occupy A1 site in Ni-Ni3A1 alloys. Bond order analysis in Hf-free case shows that lattice misfit has different effects on the Griffith work of interfacial cleavage 27int/E and the maximum theoretical shear stress Zmax of Ni and Ni3A1, contributing to the existence of anomalous strength-temperature phenomena in NiaA1 alloys. However, the addition of Hf will make the 27int/E （or Zmax） of both Ni3A1 and Ni decrease （or increase） with lattice misfit, indicating that the addition of Hf may make the anomalous strength-temperature relationship in Ni3A1 region disappear locally.

关键词： hafnium Lattice misfit Segregation Ductility

Simultaneous Determination of Zirconium and hafnium by Dual System and Dual Wavelength Spectrophotometry

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Rare Metals 1993年第4期12卷 301-304页

作者：张贵珠刘蜀利杨万龙何锡文史慧明 Nankai University Tianjin 300071China

A dual system and dual wavelength spectrophotometry (DSDWS) used to simultaneously determine Zr and Hf were proposed. Zr(Hf)-XO-CIMAB and Zr(Hf)-CAB-CDMAA-Triton X-100 were chosen as a pair of chromophoric systems. The difference of chromophoric behaviours between Zr and Hf is increased by the addition of hydrogen peroxide as masking agent and by adjustment of acidity. The apparent molar absorptivities of Zr and Hf are 2.0×105 and 5.0×104 L·mol-1·cm-1 respectively. The procedure is simple and rapid.

关键词： hafnium Measurements Spectrophotometry Wave propagation Wavemeters

Technological conditions for purification of hafnium by iodide process

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Rare Metals 2020年第2期39卷 200-204页

作者： Li-Sen Tian Yan-Xi Yin Zhi-Fang Hu Hong-Lin Jiang Zhong-Qi Li Li-Jun Wang Division of Rare Metals Materials&Metallurgy General Research Institute for Nonferrous MetalsBeijing100088China

In nuclear industry,the purity of hafnium control rod is usually significant,and the process parameters will affect the impurity contents.In this study,the four key factors(filament temperature,retort materials,feeds,and iodide reaction time)were investigated.It is found that the impurity contents of Fe,Ni in the hafnium crystal bar decrease with the K value rising.Both the retort materials and feed types have obvious influence on the impurity contents of hafnium crystal bar.The iodide reaction time has little effect on the impurity contents of hafnium crystal bar.

关键词： hafnium Purity K value Iodide

Hot Corrosion Behavior of Hf-Doped NiAl Coating in the Mixed Salt of Na_(2)SO_(4)+K_(2)SO_(4)at 900℃

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金属学报:英文版 2023年第9期36卷 1409-1420页

作者： W.L.Zhang W.Li L.B.Fu X.Peng J.Sun S.M.Jiang J.Gong C.Sun Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Advanced Research Institute for Multidisciplinary Science Qilu University of Technology(Shandong Academy of Sciences)Jinan250353China

The hot corrosion behavior of the NiAl coating and the 5Hf-NiAl coating induced by mixed salt at 900℃was investigated.Comparing with the NiAl coating,the 5Hf-NiAl coating exhibited superior hot corrosion resistance because the addition of Hf promoted the formation of protective oxide scale and reduced the growth rate of oxide scale.Therefore,internal sulfides were not present in the 5Hf-NiAl coating after hot corrosion for 140 h.Cr exhibited different distribution in the two coatings since the addition of Hf changed the hot corrosion process of the coating.Hf and Ti in the 5Hf-NiAl coating trapped and captured sulfur,preventing the penetration of sulfur into the coating.The hot corrosion mechanism of the two coating and the effects of Hf on this process were discussed in this work.

关键词： Hot corrosion hafnium Oxide scale Titanium Sulfide

Measurement of L_Ⅲ Subshell Absorption Jump Parameters of hafnium

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光谱学与光谱分析 2015年第12期35卷 3544-3548页

作者： E.Cengiz N.Saritas M.Dogan O.K.Koksal K.Karabulut G.Apaydin E.Tirasoglu Department of Physics Faculty of ScienceKaradeniz Technical University

The L_Ⅲ subshell absorption jump ratio and jump factor of hafnium have been measured using two different ways which are X-ray attenuation method and Energy Dispersive X-ray Fluorescence technique.The results obtained... 详细信息

关键词： Mass attenuation coefficient Jump ratio Jump factor hafnium

Separation of hafnium from zirconium in hydrochloric acid solution with di(2-ethylhexyl)phosphoric acid by solvent extraction

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Nuclear Science and Techniques 2019年第2期30卷 53-59页

作者： Tao Yang Guo-Xin Sun Yuan Qian Ji-Fei Ma Yu-Lan Li School of Chemistry and Chemical Engineering University of Jinan Shanghai Institute of Applied Physics Chinese Academy of Sciences

The preparation of nuclear-grade zirconium and hafnium is very important for nuclear power. The separation of hafnium from zirconium in a hydrochloric acid solution by solvent extraction was investigated with di(2-ethylhexyl)phosphoric acid(D2 EHPA). The effects of hydrochloric acid concentration, extractant concentration,diluents, and temperature on the distribution coefficient of hafnium and zirconium were studied. The species extracted were ZrOA_2·2 HA and HfOA_2-2 HA. In this process, the separation factors varied with different diluents and followed the order octane > hexane > toluene > chloroform.A high separation factor value of 4.16 was obtained under the conditions of a solution containing 0.05 mol/L HCl and0.01 mol/L D2 EHPA for the separation of hafnium from zirconium. The extraction reaction was endothermic.

关键词： Zirconium hafnium D2EHPA Solvent extraction Separation