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Journal of Alloys and Compounds
Elsevier Science S.A.
Journal of Alloys and Compounds

Elsevier Science S.A.

0925-8388

Journal of Alloys and Compounds/Journal Journal of Alloys and CompoundsSCIISTPEI
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    Systematic study of the effects of lithium deficiencies on the crystal structure and electrochemical performance of Li-rich materials

    Yan W.Li F.Yin J.Jin Y....
    9页
    查看更多>>摘要：A series of Li-rich materials with lithium deficiencies are obtained by a mild sol-gel and high-temperature calcination method. We use conventional test methods, such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy, to analyze the crystal structure and morphology of as-prepared materials. The results show that the Li1.1Mn0.54Co0.13Ni0.13O2 (named L1.1) displays superior electrochemical performance, that is, the discharge capacities are 303.9 and 145 mAh g?1 at rate of 0.1 C and 5 C, respectively. The excellent rate capability is mainly attributed to the formation of lithium vacancy and the formation of distorted lattice fringes, which enlarged the Li slab and changed the local structures in the L1.1 material.
      原文链接:
    • NSTL
    • Elsevier

    Analysis of structural transformation in nanocrystalline Y2O3 during high energy ball milling

    B.R. V.K.Dasgupta A.Ghosh C.Sinha S.K....
    9页
    查看更多>>摘要：In-depth understanding of the structural transformation mechanism in nanocrystalline yttria (Y2O3) is crucial to design advanced materials satisfying a wide range of technical demands. Present study investigates the structural modification in cubic Y2O3 nanopowders induced by high energy ball-milling as a function of milling duration. Y2O3 nanopowder with an initial crystallite size of 25–50 nm was subjected to high energy ball milling (1000 rpm) for incremental time periods up to 30 h. X-ray diffraction (XRD) and Rietveld analysis were employed to study the phase evolution, crystallite size, and strain at every stages of milling. High Resolution Transmission Electron Microscopy (HR TEM) and Electron Energy Loss Spectroscopy (EELS) is utilized to realize the mechanisms involved in phase transformation. It is observed that as milling duration progresses, the cubic Y2O3 gets refined and gradually transforms to the monoclinic phase. It is also apparent that at finer sizes, the monoclinic phase is preferred over the cubic one. The critical crystallite size for the monoclinic phase to stabilize is observed to be ~ 13 nm. Results show the complete structural modification after 30 h of milling duration.
      原文链接:
    • NSTL
    • Elsevier

    Self-propagating high–temperature synthesis of porous graphene by magnesiothermic reaction as high–performance electrochemical electrode material

    Su S.Tian Y.Li S.Ping D....
    7页
    查看更多>>摘要：Graphene is widely used in supercapacitors due to its large specific surface area and excellent electrical conductivity. However, a large scale efficient and sustainable production of high–quality graphene is still an urgent challenge. We report a controllable self-propagating high–temperature synthesis (SHS) process to convert CO2 with a mixed powder of magnesium and zinc into porous graphene (PG). The prepared PG contains 3–6 layers, with a plenty of uniform 2–4 nm mesopores, and has a specific surface area as high as 1458 m2 g?1. The obtained PG was used as an electrode material for the supercapacitor and exhibited a superior capacitance performance. At a current density of 1 A g?1, the specific capacitance can reach 177 F g?1. Capacitance retention rate is as high as 91% after 10,000 cycles at a current density of 5 A g?1. In addition, the charge–discharge curve remains approximately triangular at a current density of 20 A g?1, which shows satisfactory capacitance properties. We expect that our results will contribute to the development of the large-scale graphene synthesis technology based on a use of the SHS method aimed for the application as high–performance supercapacitor materials.
      原文链接:
    • NSTL
    • Elsevier

    Interface optimization strategy for enhancing the mechanical and thermal properties of aligned graphene/Al composite

    Hou B.Liu P.Wang A.Xie J....
    12页
    查看更多>>摘要：In the present work, we firstly used the first-principles calculation and molecular dynamics (MD) simulation to predict the graphene/Al interfacial properties, and it is found that graphene defect and Al alloying Cu(Mg) could be an effective method for enhancing the graphene/Al interfacial bonding strength and thermal conductance due to the pronounced hybridization and phonon-phonon coupling effect between interfacial Cu(Mg) atoms and C atoms near the vacancy. Then we successfully prepared the aligned graphene/2024Al composite with the optimized interfacial microstructure by the method of powder metallurgy. The results showed that the tensile strength of 0.5 wt% graphene/2024Al composite could reach 325 MPa and is ~38.3% higher than that of the 2024Al matrix, while the plasticity keeps almost unchanged. The thermal conductivity of 0.5 wt% graphene/2024Al composite is 16.3% (10.9%) higher than 2024Al matrix along (or vertical to) the aligned direction of graphene.
      原文链接:
    • NSTL
    • Elsevier

    Preparation of porous TiNi-Ti alloy by diffusion sintering method and study of its composition, structure and martensitic transformations

    Anikeev S.G.Artyukhova N.V.Shabalina A.V.Hodorenko V.N....
    8页
    查看更多>>摘要：The study demonstrates a method for controlling not only the phase composition but also the atomic composition of TiNi matrix in porous TiNi-Ti alloys developed for biomedical uses as implants. The alloys were obtained from TiNi powder which was sintered with Ti powder added at as much as 0–10 at%. The structure, phase and chemical composition of the produced TiNi-Ti alloys was investigated with respect to the amount of Ti added into the material. It is shown that in the sintered product containing 5 at% and more of Ti additive, the composition of its TiNi matrix becomes close to equiatomic (with Ti:Ni atomic ratio ~1), and the excessive Ti precipitates as secondary phases Ti2Ni and Ti3Ni4. In parallel, with increase in Ti additive from 0–10 at%, the structure of the precipitating Ti2Ni type phases changes its morphology from separate spherical or pyramidal precipitates to large dendritic formations. The direct martensitic transformation from austenite to martensite in all the samples was found to proceed in two stages and through the R-phase (B2→R→B19′). Thermoresistive analysis demonstrated that TiNi-Ti samples with 5 and more at% of Ti had their characteristic starting temperature of martensite transition stabilizing at ~57 °C (330 K). This implies that the sample with 5 at% of Ti additive exhibited desired martensite transition temperatures, while containing a minimum concentration of secondary-phase precipitates in its matrix which deteriorate its properties. Thus, for the first time, we show that a very simple preparation approach based on sintering powders of TiNi and Ti is capable of producing porous TiNi-Ti alloys with properties optimized for fabricating bone implants.
      原文链接:
    • NSTL
    • Elsevier

    Development of Co0.5Ho0.5Fe2O4/graphene hybrid nanocomposites electrodes for all-solid-state printable micro-supercapacitor on flexible substrates

    Mahmoud W.E.Al-Ghamdi A.A.Alshahrie A.Al-Turki Y.A....
    9页
    查看更多>>摘要：Herein, we report the synthesis of Co0.5Ho0.5Fe2O4/graphene hybrid nanocomposite electrodes for all-solid-state printable supercapacitor on flexible substrate using a one-step laser scribe approach. The structure, morphology, oxidation state, and elemental composition characteristics were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), selected area of electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) measurements. The results revealed that the laser scribe can not only used to print the films on the flexible substrate but also has high capability to convert the graphene oxide and the cobalt, holmium and iron salts to Co0.5Ho0.5Fe2O4/graphene hybrid nanocomposite during printing this suspension on a flexible substrate. The cyclic voltammetry and the galvanostatic charge/discharge measurements revealed that the decoration of the surface of graphene with Co0.5Ho0.5Fe2O4 nanocrystals increases the operational voltage window to 1.5 V. The combination of the developed polyethylene glycol/silica/lithium triflates (48:37:15) ionic gel with the Co0.5Ho0.5Fe2O4/graphene hybrid electrodes exhibits a capacitance of 590 F.g?1 (204 mF.cm?2). Furthermore, the printed supercapacitor on the flexible substrate exhibited an energy density of 161.3 Whkg?1 and a maximum power density of 211kWkg?1. The developed Co0.5Ho0.5Fe2O4/LSG hybrid nanocomposite supercapacitor showed outstanding capacitive performance under harsh mechanical conditions.
      原文链接:
    • NSTL
    • Elsevier

    Nanocrystalline structure remarkably enhances oxidation resistance of Fe-20Cr-5Al alloy

    Kumar R.Raja V.S.Parida S.Raman R.K.S....
    8页
    查看更多>>摘要：The present study investigates the oxidation behavior of nanocrystalline (NC) and microcrystalline (MC) Fe-20Cr-5Al alloys at 900 oC. A protective layer of Al2O3 layer is formed at a relatively lower Al content in the case of microcrystalline Fe-Cr-Al alloys containing sufficient amounts of Cr (i.e. third element effect). The required critical content of Al for the formation of a full-fledged Al2O3 layer can further be reduced by the nanocrystalline structure. We demonstrate here that nanocrystalline Fe-20Cr-5Al alloy becomes capable of developing a protective layer of Al2O3. The results show that nanocrystallization presumably reduces the Al requirement below that is necessary for the “third element effect” of Cr. Consequently, the nanocrystalline Fe-20Cr-5Al alloy oxidized at an insignificant rate (c.f., its microcrystalline counterpart). Accordingly, the NC Fe-20Cr-5Al alloy follows logarithmic oxide growth kinetics, whereas the MC Fe-20Cr-5Al alloy follows parabolic kinetics. Additionally, the MC alloy exhibits four times higher weight gain than the NC alloy after 60 h of oxidation.
      原文链接:
    • NSTL
    • Elsevier

    Corrigendum to “Grain boundary effect on the microstructure of solution-treated Fe-rich Sm-Co-Fe-Cu-Zr alloys” [J. Alloy. Compd. 853 (2021) 156974] (Journal of Alloys and Compounds (2021) 853, (S0925838820333387), (10.1016/j.jallcom.2020.156974))

    Musa M.Song X.Zhou X.Jia W....
    2页
    查看更多>>摘要：The authors regret the original version of the above article contains an error for the author's affiliations. The correct affiliations are shown below. Munzali Musa a,c, Xin Song a, Xianglong Zhou a, Wentao Jia a, Tao Yuan a,b, Tianyu Ma a,*, Xiaobing Ren a,d. a. Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, and MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, Xi'an 710049, China. b. The Southwest Applied Magnetism Research Institute, Mianyang 621000, China. c. Nigeria Police Academy, Faculty of Science, Department of Physics, P.O. Box 14830, Kano State, Nigeria. d. National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan. The authors would like to apologise for any inconvenience caused.
      原文链接:
    • NSTL
    • Elsevier