首页期刊导航|Journal of Alloys and Compounds
期刊信息/Journal information
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
正式出版
收录年代

    Influence of Ni additions on the microstructure and tensile property of W-Cu composites produced by direct energy deposition

    Wang G.Qin Y.Yang S.
    9页
    查看更多>>摘要:In this paper, the direct energy deposition technology was applied to produce the W-Cu composites. The Ni powder ranging from 1 to 10 wt% was added into the W-Cu mixed powder to improve the wettability between W and Cu. The influence of Ni additions on the microstructural characterization, phase composition, relative density, and tensile property of thin wall samples was investigated. The morphology and temperature history of the melt pool were detected to analyze the microstructure evolution. The research results show that there were plenty of aggregations of W particles and residual pores in the joint area of the 60W40Cu thin wall sample. Due to the effect of Ni additions on reducing the surface tension between W and liquid Cu, the W particles tended to be uniformly distributed in the matrix with the increase of Ni content. Meanwhile, Ni additions decreased the cooling rate of the melt pool, which promoted the transformation from columnar grains to dendrites in the matrix. Furthermore, the Ni additions could significantly increase the relative density and tensile strength of W-Cu composites. When Ni content was increased from 0 wt% to 10 wt%, the relative density rose from 83.1% to 98.4%, the tensile strength of longitudinal and transverse specimens was nearly 3 and 5 times respectively as high as that of the specimens without Ni content.

    Investigation of Sn-containing precursors for in-plane GeSn nanowire growth

    Zheng L.Gong R.Chen W.Azrak E....
    8页
    查看更多>>摘要:The formation of Sn catalyst nanoparticles (NPs) for the growth of GeSn nanowires (NWs) requires the identification of suitable Sn-containing precursors. In this work, various Sn-containing precursors such as Sn, SnO2 and indium tin oxide (ITO) thin films as well as SnO2 nanoparticles have been investigated. Sn and SnO2 thin films did not produce NWs. This reveals that the catalyst density, as well as their wetting on the amorphous layer, play vital roles on the growth of GeSn NWs. Conversely, Ge nanocrystals (NCs) were successfully grown from ITO thin films deposited on c-Si substrates. A good crystallinity was obtained when there is no interfacial SiOx layer on the crystalline Si substrate. Finally, using SnO2 NPs allowed us to grow GeSn NWs. Their morphology is strongly impacted by the annealing environment: hydrogen atmosphere with different pressures or hydrogen plasma, the later providing the best results. The nanostructure and composition of GeSn NWs were investigated in detail. These results could pave the way to grow in-plane Ge nanostructures within several types of Sn-containing materials.

    One-step synthesis based on non-aqueous sol-gel conductive polymer-coated SnO2 nanoparticles as advanced anode materials for lithium-ion batteries

    Zhang Z.Wu D.Jiang L.Liang F....
    10页
    查看更多>>摘要:SnO2 has been considered a promising anode material for lithium-ion batteries (LIBs) based on its high theoretical capacity (1494 mA h g?1). Unfortunately, the electrochemical properties, including rate performance and stability for SnO2-based materials, are still restrained by huge volume expansion and weak electron dynamics. Hence, we developed a one-step strategy for the synthesis based on non-aqueous sol-gel polypyrrole (PPy)-encapsulated SnO2 nanoparticles to solve the above issues. The synthesized material exhibits excellent dispersibility, and the SnO2 nanoparticles are encapsulated by the conductive coating (SnO2 @PPy-2). As an anode, SnO2 @PPy-2 demonstrates excellent electrochemical capabilities compared to pure SnO2 and SnO2 @PPy-1(based on pure SnO2 encapsulated PPy). SnO2 @PPy-2 not only exhibits 783.8 mAh g?1 and 932.6 mAh g?1 capacities at 0.5 A g?1(200 cycles) and 0.2 A g?1(100 cycles) but also retains an excellent rate performance for 560.2 mA h g?1 at 2 A g?1. This superior Li-storage performance can be ascribed to the reduced nanosize for SnO2 and the conductive polymer coating, which significantly enhances mass transfer efficiency. The existence of PPy dramatically restricts volume expansion and the agglomeration of Sn intermediates during charge/discharge. This work has also provided novel ways for the preparation of other disperse metal oxide/conductive-polymer composites.

    Enhancing the ion accessibility of Ti3C2Tx MXene films by femtosecond laser ablation towards high-rate supercapacitors

    Zheng X.
    8页
    查看更多>>摘要:MXenes have attracted tremendous attention in the area of electrochemical energy-storage devices owing to their high electrical conductivity, pseudocapacitance and two-dimensional lamellar structure. Nevertheless, MXene flakes intrinsically tend to lie flat and restack, resulting in highly tortuous ion transport pathways and inferior ion accessibility. Herein, we develop a femtosecond laser ablation strategy to fabricate flexible and high-performance MXene ribbon supercapacitor electrodes. The fabricated MXene ribbons have porous edges with exposed continuous lamellar channels, which shortens the H+ transport pathways, impregnates with sufficient electrolyte, benefits for H+ intercalation and ion storage. The resultant MXene ribbons exhibit high specific capacitance (1308.3 mF/cm2), good rate capability and long cycling life (95% capacitance retention and 92% coulombic efficiency after 30,000 cycles). This work provides a new strategy for the rational structure design of high-rate MXene-based supercapacitor electrodes and lays the foundation for the next generation high-performance energy storage devices.

    [Ga]/([Ga]+[In]) profile controlled through Ga flux for performance improvement of Cu(In,Ga)Se2 solar cells on flexible stainless steel substrates

    Kawano Y.Chantana J.Minemoto T.Mavlonov A....
    10页
    查看更多>>摘要:We present flexible Cu(In,Ga)Se2 (CIGSe) solar cells on stainless steel substrates with enhanced photovoltaic performance. CIGSe absorbers with thicknesses of 1.4 and 1.0 μm were deposited by the multilayer precursor method using precursor depositions of Ga–Se/In–Se/Cu–Se and then annealed under In–Se/Ga–Se/In–Se evaporations. The pronounced double-graded [Ga]/([Ga] + [In]) (GGI) profiles of the 1.4-μm-thick and 1.0-μm-thick CIGSe films were obtained using a relatively high Ga flux (up to 5.4 × 10?4 Pa), which shortened the annealing time. The pronounced double-graded GGI profiles of the 1.4-μm-thick and 1.0-μm-thick CIGSe films and CuInSe2 phase separation remarkably enhanced photovoltaic performances because a high back slope in the double-graded GGI profile induces back surface field, and the pronounced double-graded GGI profile with CuInSe2 phase separation yields the minimum GGI values, increasing light absorptionat longer wavelengths and in turn, conversion efficiency (η). Ultimately, η values of the flexible CIGSe solar cells increased to 17.3%, 17.2%, and 14.3% for CIGSe films with thicknesses of 2.5, 1.4, and 1.0 μm, respectively.

    Formation and beneficial effects of the amorphous/nanocrystalline phase in laser remelted (FeCoCrNi)75Nb10B8Si7 high-entropy alloy coatings fabricated by plasma cladding

    Chen H.Cui H.Jiang D.Song X....
    11页
    查看更多>>摘要:High-entropy amorphous composite coatings have high potential application value in the industrial field due to their excellent performance. (FeCoCrNi)75Nb10B8Si7 high-entropy alloy coatings with amorphous/nanocrystalline phases were prepared by plasma cladding and subsequent laser remelting. The phase, microstructure, mechanical properties, and wear resistance of the coatings were studied. Detailed characterization indicated that the microstructure of the plasma cladding coating consisted of the body-centered cubic (BCC) phase, whereas that of the laser remelting coatings consisted of the Fe and Ni-rich BCC phase in the dendritic area and the Nb, B, and Si-rich nanocrystalline-face-centered cubic (nano-FCC) + amorphous phases in the interdendritic area. Excellent mechanical properties were observed, including high microhardness, high nanohardness (H) to elastic modulus (E) ratio (H/E), high H3/E2, and a high elastic recovery rate (η). Furthermore, the coefficient of friction (COF) was lower in the laser remelting coatings (0.6) than in the plasma cladding coating (0.7), which was attributed to severe adhesive wear of the plasma cladding coating and abrasive and slightly adhesive wear of the laser remelting coatings. The microstructure evolution and strengthening contribution of the interdendritic structure in the laser remelting coatings and the relationship between the microstructure and mechanical properties and wear resistance were analyzed.

    Crystal structure and thermochromic behavior of the quasi-0D lead-free organic-inorganic hybrid compounds (C7H9NF)8M4I16 (M = Bi, Sb)

    Zhao X.C.Fu Y.K.Wang C.Gu Q....
    8页
    查看更多>>摘要:The quasi 0D lead-free thermochromic organic-inorganic hybrid single crystals (C7H9NF)8M4I16 (M = Bi, Sb) were synthesized by a conventional solvothermal reaction method. The crystal structures were analyzed using single crystal X-ray diffraction (SXRD). Interestingly, as the temperature increases, the (C7H9NF)8M4I16 (M = Bi, Sb) crystals exhibit a peculiar thermochromic phenomenon. In order to explore the phenomenon of thermochromism, temperature dependent ultraviolet?visible-near-infrared (UV–vis–NIR) absorption spectra were measured. The bandgaps of (C7H9NF)8Sb4I16 and (C7H9NF)8Bi4I16 at room temperature are 2.34 eV and 2.1 eV, respectively, and they gradually decrease as the temperature increases. Combined with ab initio molecular dynamics (AIMD), the reduction of the bandgap at higher temperature and the occurrence of thermochromism could be caused by the stronger electronic activity (thermal excitation). The thermochromic characteristics of these low-dimensional organic-inorganic hybrid metal halides will provide alternative materials for smart windows temperature sensors, visual thermometers, and daylight control glasses and beyond.

    Self-powered TiO2 NRs UV photodetectors: Heterojunction with PTTh and enhanced responsivity by Au nanoparticles

    Zhang H.Abdiryim T.Li J.Liu H....
    13页
    查看更多>>摘要:In this paper, novel self-powered p-n heterojunction UV photodetectors (TiO2 nanorod arrays/polyterthiophene (TiO2 NRs/PTTh) and TiO2 nanorod arrays/Au nanoparticles/polyterthiophene (TiO2 NRs/Au/PTTh)) are successfully constructed by combining the hydrothermal method and electrochemical deposition method. The structures, morphologies and photocurrent response properties of TiO2 NRs/PTTh and TiO2 NRs/Au/PTTh heterojunction UV photodetectors are systematically studied. These results show that TiO2 NRs/PTTh UV photodetector has self-powered performance, and also exhibit high sensitivity, good stability and fast response. Furthermore, the detection performance of UV photodetector could be further improved by using Au NPs as the middle layer due to the pyro-phototronic effect between Au NPs and TiO2 NRs. The responsivity (R) of TiO2 NRs/PTTh and TiO2 NRs/Au/PTTh UV photodetectors are respectively 0.0774 mA/W and 1.894 mA/W, and the detectability (D*) are respectively 2.155 × 109 Jones and 1.666 × 1010 Jones. Compared with the TiO2 NRs/PTTh UV photodetector, the rise time (τr) and fall time (τf) of TiO2 NRs/Au/PTTh UV photodetector are obviously shortened. And these results also confirm that the TiO2 NRs/Au/PTTh UV photodetector with heterojunction structure is a suitable candidate for self-powered UV photodetector. This work offers an effective strategy for the development of self-powered UV photodetectors.

    Mechanical alloying fabrication of nickel/cerium/MgH2 nanocomposite for hydrogen storage: Molecular dynamics study and experimental verification

    Akbarzadeh F.Z.Rajabi M.
    11页
    查看更多>>摘要:This study employed mechanical alloying (MA) to synthesize magnesium-based nanocomposites for hydrogen storage. To fabricate the composite materials, firstly, the vacuum arc re-melting (VAR) method was used to make cerium–nickel (Ce-Ni) alloy with two compositions, including 50Ce-50Ni (wt%) (CN1) and 25Ce-75Ni (wt%) (CN2). Then, 10 wt% of these alloys was milled with magnesium hydride (MgH2) for 5 and 15 h. The impact of milling time on the hydrogen desorption features of the prepared nanocomposites was estimated by the thermal analyzer method and compared to pure MgH2. The molecular dynamics (MD) method was employed to describe the enthalpy change of the nanocomposites mentioned above and pure MgH2 at the atomic scale. Experimental enthalpy results calculated by measuring the peak area in DSC curves also confirmed the molecular dynamics data. Since the enthalpy values of the manufactured nanocomposites were significantly lower than pure MgH2 (?75 kJ/mol), the lower desorption temperature in these specimens was justified.

    Influence of different flux-materials on phase structure, morphology, photoluminescence, thermal stability, and cathodoluminescence in Ba2La0.9Eu0.1SbO6 phosphors

    Hua Y.Yu J.S.
    8页
    查看更多>>摘要:Recently, flux-materials have attracted considerable attention for improving the photoluminescence (PL) properties of luminescent materials. Herein, the phase structure, morphology, PL property, thermal stability, and cathodoluminescence (CL) property of Ba2La0.9Eu0.1SbO6 phosphors with and without the flux-materials of NH4F, C6H8O7, and H3BO3 were investigated and compared. At first, these mentioned flux-materials would barely affect the crystal structure through analyzing the X-ray diffraction patterns and Rietveld refinements. However, the morphology, PL intensity, thermal stability, lifetime, and CL performance were implicated by adding the flux-materials. Especially, the C6H8O7 flux-material could obviously improve the emission intensity and CL property of Ba2La0.9Eu0.1SbO6 phosphors with respect to the other samples. In addition, these flux-materials could enhance thermal stability and lifetime. In terms of quantum yield, the H3BO3 flux-material has the best optimization capabilities. Briefly, this work would provide a deep insight into a kind of suitable flux-materials to optimize luminescent materials in the synthesized processes.