显示样式:     当前分类: 材料    当前期刊: Journal of Alloys and Compounds    加入关注    导出
我的关注
我的收藏
您暂时未登录!
登录
  • MoSi2/(Mo, Ti)Si2 dual-phase composite coating for oxidation protection of molybdenum alloy
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-21
    Wei Li, Jinglian Fan, Yan Fan, Lairong Xiao, Huichao Cheng
    更新日期:2017-09-21
  • Control of electrical to thermal conductivity ratio for p-type LaxFe3CoSb12 thermoelectrics by using a melt-spinning process
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-21
    Geonsik Son, Kyu Hyoung Lee, Hae-Woong Park, Arnaud Caron, Il-Ho Kim, Soonil Lee, Soon-Mok Choi

    In this work we improved the thermoelectric figure of merit ZT in a LaxCoFe3Sb12 (x = 0.80, 0.85, 0.90) skutterudite system by applying a conductivity ratio (electrical to thermal) control method based on the phonon-glass electron-crystal (PGEC) approach. Polycrystalline bulks of LaxCoFe3Sb12 were prepared by melt-spinning and subsequent spark plasma sintering. Based on the thermoelectric transport properties and microstructural analysis, we found that large amount of La-filler (x ≥ 0.9) in the LaxCoFe3Sb12 system is necessary to increase the conductivity ratio required to improve the thermoelectric properties in the LaxCoFe3Sb12 system. Resultantly, the maximum ZT value of 0.87 was obtained at 723 K in the heavily filled La0.9CoFe3Sb12. We discuss our results on the basis of the filling level dependence of the rattling effect and on the formation of the skutterudite single phase. We also confirm that a large amount of La-filling level is necessary to meet the electrical neutrality condition of the p-type LaxCoFe3Sb12 skutterudite system.

    更新日期:2017-09-21
  • Structural and dielectrics properties of Pr3+ doped BaTi0.925(Yb0.5Nb0.5)0.075O3 ceramics
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-21
    C. Chalfouh, A. Lahmar, N. Abdelmoula, H. Khemakhem

    Ba1-xPr2x/3Ti0.925(Yb0.5Nb0.5)0.075O3:(xPrBTYN) (0.02 ≤ x ≤ 0.08) ceramics were prepared by a high temperature solid-state reaction technique. The effects of the Pr3+ addition to structural and dielectric properties were examined. The X-ray study has evidenced a cubic single phase in the Pm-3m space group. Raman spectra showed that the replacement of the Ba2+ by Pr3+ ions induced a down shift of active modes accompanied with a significant reduction in the intensity. Further, a new mode appeared at 115 cm−1 with an intensity depended on the composition. Dielectric study as a function of temperature and frequency of ceramic samples has revealed a normal ferroelectric behavior where x ≤ 0.06, instead to a relaxor character in the case of ceramic with an optimum value of Pr3+ doping (x = 0.08).

    更新日期:2017-09-21
  • Antiferromagnetic behaviour and dielectric relaxation of xBa2FeNbO6–(1-x)LaFeO3 [x = 0.1, 0.3, 0.5]
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-21
    Ram Awdhesh Kumar, Alo Dutta, P.K. Mukhopadhyay, T.P. Sinha

    In this work we have investigated the magnetic and dielectric properties of xBa2FeNbO6–(1-x)LaFeO3 [x = 0.1, 0.3, 0.5] prepared by the solid state reaction technique. The Rietveld refinement of the X-ray diffraction pattern of the samples is performed to confirm the phase formation as well as the crystal structure of the materials. The crystal structure and the phase formation of the materials are studied by Rietveld refinement of the X-ray diffraction data. The x = 0.1 and 0.5 materials have orthorhombic Pbnm and cubic Fm3m crystal symmetry respectively. Whereas x = 0.3 material has both Pbnm (83.64%) and Fm3m (16.36%) phases. The effect of lattice distortion on the magnetic and dielectric properties has been discussed. The temperature dependent magnetization study reveals the anti-ferromagnetic behaviour of the materials. The magnetic field dependence magnetization curve indicates the canting of Fe3+ spins in these materials like LaFeO3. The value of magnetization has increased with respect to pure LaFeO3. The dielectric relaxation of the materials is analyzed within impedance and electric modulus mechanisms. The value of conductivity and dielectric constant increases with the increase of x value. Two semi-circular arcs in the complex impedance plane plot originate due to the grain and grain-boundary contributions which give rise to two dispersion regions in the frequency dependence conductivity spectra of the materials. The complex impedance plane plot is described by an electrical equivalent circuit consisting of two parallel RC elements connected in series.

    更新日期:2017-09-21
  • Preparations and de/re-hydrogenation properties of LixNa3-xAlH6 (x=0.9–1.3) non-stoichiometric compounds
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-21
    Xiaolu Fan, Yao Zhang, Yunfeng Zhu, Cassandra Phillips, Xinli Guo, Jian Chen, Zengmei Wang, Liquan Li

    Mixed alkali alanates LixNa3-xAlH6 have been successfully synthesized by means of grinding mixtures of Li3AlH6 and Na3AlH6 in specific molar ratios. Non-stoichiometric LixNa3-xAlH6 compounds with single perovskite-type structures (space group Fm-3m) can be formed only within the composition range of x = 0.9–1.3. Li1.3Na1.7AlH6 exhibits superior hydrogen storage properties over other LixNa3-xAlH6 compounds. Its onset dehydrogenation temperature (∼423 K) was lowered by more than 40 K from other samples in temperature programmed dehydrogenation (TPD) curves. Also, the dehydrogenation capacity of Li1.3Na1.7AlH6 (3.45 wt.%) is the highest among the compounds. The dehydrogenation enthalpy values of LixNa3-xAlH6 decreased as x increased from 0.9 to 1.3 according to the results by isothermal pressure-composition (PCI) curves and van't Hoff plots. It shows that the dehydrogenation Li1.3Na1.7AlH6 (49.7 kJ mol H2−1) was greatly destabilized from that of LiNa2AlH6 (68.1 kJ mol H2−1). Furthermore, the apparent activation energy of dehydrogenation for Li1.3Na1.7AlH6 (138.1 kJ mol−1) was remarkably lowered from that of LiNa2AlH6. This illustrates that Li1.3Na1.7AlH6 exhibits enhanced dehydrogenation kinetics from that of LiNa2AlH6.

    更新日期:2017-09-21
  • A novel MoS2/C nanocomposite as an anode material for lithium-ion batteries
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-21
    Yan Liu, Daoping Tang, Haoxiang Zhong, Qianyu Zhang, Jianwen Yang, Lingzhi Zhang

    A novel molybdenum disulfide/carbon (MoS2/C) nanocomposite is synthesized by a simple hydrothermal method using glucose as a carbon source and Pluronic F127 as promoting agent in presence of MoS2 nanoparticles and followed by carbonization. Pluronic F127 is used as an essential agent which inhibits the spontaneous formation of carbon micropheres during the hydrothermal reaction. The composite electrode exhibits excellent cycling stability and rate capability, delivering a reversible capacity of 882.6 mA h g−1 at a current density of 50 mA g−1 and a capacity retention of 82.8% after 100 cycles at a current density of 100 mA g−1. At a higher current density of 300/500 mA g−1, it still retains a capacity of 603.6/461.6 mA h g−1 respectively, as compared to 295.6/228.4 mA h g−1 for the pristine MoS2 electrode. The composite shows favorable electrochemical kinetics compared with pristine MoS2 due to the incorporation of homogenous conductive carbon layer and its nanostructured morphology.

    更新日期:2017-09-21
  • A strategy to deposit nano metals in multi-layer graphene for scalable synthesis of high performance anode materials in lithium ion battery
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-21
    Q.Q. Wang, J.J. Xu, R. Li, Z. Lin, B.H. Liu, Z.P. Li
    更新日期:2017-09-21
  • High coercivity and squareness realized in polycrystalline AlN-buffered Cu-doped Sm-Co thin films with perpendicular anisotropy
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-21
    Tongbo Zhang, Yang Yang, Yigao Xie, Yanqing Fu, Weibin Cui, Xinguo Zhao, Wei Liu, Zhidong Zhang, Qiang Wang
    更新日期:2017-09-21
  • Efficient white LEDs with bright green-emitting CsPbBr3 perovskite nanocrystal in mesoporous silica nanoparticles
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-21
    Xiaoxuan Di, Ludi Shen, Jutao Jiang, Meiling He, Yinzi Cheng, Lei Zhou, Xiaojuan Liang, Weidong Xiang
    更新日期:2017-09-21
  • Lorentz force induced magnetoelectric effect in cylindrical composites with PZT/magnetostrictive and nonmagnetic metal layers
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-21
    Lirong Xu, Lijie Qiao, De'an Pan, Alex A. Volinsky

    Lorentz force-piezoelectric coupled magnetoelectric (ME) effect and piezomagnetic-piezoelectric coupled ME effect were compared in PZT/nonmagnetic and PZT/magnetostrictive metal cylindrical layered composites under axial magnetic fields. While only the Lorentz force-piezoelectric ME effect is observed in PZT/brass and PZT/Al cylinders, both ME effects are present in PZT/magnetostrictive Ni cylinder. The ME voltage linear dependence on DC magnetic field and constant −90° ME voltage phase reflect the Lorentz force-piezoelectric ME effect. For the PZT/Ni cylinder under low DC magnetic field, the ME voltages from the two ME effects tend to be anti-phase, and the piezomagnetic-piezoelectric ME voltage is much higher than the Lorentz force-piezoelectric ME voltage. However, under high DC magnetic field, the Lorentz force-piezoelectric ME effect plays a dominant role. These results indicate that the PZT/Ni cylinder is favorable to DC magnetic field detection in wide range.

    更新日期:2017-09-21
  • Recent development in lithium metal anodes of liquid-state rechargeable batteries
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    S.F. Liu, X.L. Wang, D. Xie, X.H. Xia, C.D. Gu, J.B. Wu, J.P. Tu
    更新日期:2017-09-21
  • Effect of Ta on microstructural evolution and mechanical properties of a solid-solution strengthening cast Ni-based alloy during long-term thermal exposure at 700 °C
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Shuang Gao, Jieshan Hou, Fei Yang, Yongan Guo, Lanzhang Zhou

    Effect of Ta on microstructural evolution and mechanical properties of a solid-solution strengthening cast Ni-based superalloy, IN617B alloy, considered as a potential candidate for castings in 700 °C advanced ultra-supercritical (A-USC) coal-fired power plants, has been studied in this paper. Detailed observation reveals the alloys with different contents of Ta have similar solution treated microstructure. During long-term thermal exposure at 700 °C, Ta addition refines γ′ particles and enhances the thermal stability of γ′ phase by decreasing the γ-γ′ lattice misfit. With increasing Ta content the solubility of Mo in matrix decreases, which promotes the transformation of film-like M23C6 at grain boundaries (GBs) into blocky M6C carbide with the reaction of <img height="22" border="0" style="vertical-align:bottom" width="132" alt="View the MathML source" title="View the MathML source" src="http://origin-ars.els-cdn.com/content/image/1-s2.0-S0925838817332437-si1.gif">M23C6→−Cr+Mo,TaM6C. Consequently, the morphology of GB carbide changes from continuous film structure to dispersed block structure. In addition, local concentration of metal elements leads to the precipitation of trace amount of σ phase which is not affected by Ta concentration. Nearly all the tensile properties at 700 °C of the alloy after long-term thermal exposure are improved noticeably with the increase of Ta content. But, the plasticity of the alloy with 2.0 wt. % Ta addition decreases remarkably due to the excessive Ta content leading to severe M6C coarsening at GBs. The alloy achieves optimal mechanical properties with about 1.0 wt. % Ta content.

    更新日期:2017-09-21
  • Ternary transition metal oxide derived from Prussian blue analogue for high-performance lithium ion battery
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Xiaocheng Hou, Guoyin Zhu, Xiaoying Niu, Ziyang Dai, Zhihui Yin, Qiuchun Dong, Yizhou Zhang, Xiaochen Dong
    更新日期:2017-09-21
  • Fabrication of N-doped &SnO2-incorporated activated carbon to enhance desalination and bio-decontamination performance for capacitive deionization
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Ahmed S. Yasin, Jongku Jeong, Ibrahim M.A. Mohamed, Chan Hee Park, Cheol Sang Kim
    更新日期:2017-09-21
  • Influences of Fe content on the fabrication of FeSe superconductors with high-energy ball milling aided sintering process
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Shengnan Zhang, Botao Shao, Gaoyang Zhao, Jixing Liu, Jianqing Feng, Chengshan Li, Pingxiang Zhang

    FexSe superconducting bulks with different norminal Fe content from x = 1.00 to 1.20 have been fabricated with high-energy ball milling (HEBM) aided sintering process. The influences of original Fe contents on the phase composition, microstructures and superconducting properties were systematically investigated. It was noticed that with the increase of original Fe content, the nonsuperconducting δ-FeSe phase content decreased, while the content of residual Fe increased correspondingly. Meanwhile, the increasing original Fe content could also cause the increase of FeSe crystal size, therefore, the (00l) texture of FeSe bulks was enhanced, which would be beneficial to the intergrain connections. Mössbauer spectra have been performed to study the magnetic orders in obtained FeSe bulks. A clear hyperfine magnetic sextet corresponding to the magnetic ordering with Hf of 333.0 kOe can be related to residual Fe in the bulks with Fe content higher than 1.10. The magnetic and superconducting properties of obtained bulks underwent a systematical change with original Fe content. The increasing Fe content can obviously enhance the superconducting performance of FeSe bulks and the optimal critical temperature, Tc of 9.0 K was obtained with original Fe content of 1.20.

    更新日期:2017-09-21
  • Cyclic oxidation behavior and oxide scale adhesion of Al/NiCrAlY coating on pure titanium alloy
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Xue Gong, Ruirun Chen, Qi Wang, You Wang, Nannan Zhang, Zhongli Zhang, Hengzhi Fu

    Al and Al/NiCrAlY coatings were deposited on pure titanium substrate by air plasma spraying method. Cyclic oxidation behavior and oxide scale adhesion at 800 °C for 100 cycles were investigated. For the single Al coating, a severe spalling of oxide scale and elemental interdiffusion occurred after 100 cycles. The mass loss of the single Al coating has reached to 1.39 mg/cm2. The oxide scale on the duplex Al/NiCrAlY coating kept a good bonding with the underlay coating. The addition of NiCrAlY layer inhibited the outward diffusion of Ti atoms and inward diffusion of Al atoms. The propagation of cracks and the formation of pores were also suppressed by NiCrAlY layer. As a result, the duplex Al/NiCrAlY coating possessed a superior cyclic oxidation resistance.

    更新日期:2017-09-20
  • In-situ reaction synthesis of composite coating on titanium alloy for improving high temperature oxidation resistance
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Wenbo Du, Shasha Zhang, Xixi Luo, Xuewei Tao, Chao Fang, Zhengjun Yao

    A technique to synthesize in-situ α-Al2O3 composite coating on TC11 is explored for protecting titanium alloys against oxidation at high temperature. Results reveal that an oxygen barrier composite coating is formed on the substrate at 1073 K, which is composed of the compact α-Al2O3 layer and transition layer. It is effective to protect TC11 from the internal and external oxidation, the oxidation rate and average oxide thickness of in-situ composite coating are much less and thinner than those of substrate. At 973 K, The rate and thickness with the composite coating are 0.01 mg2/cm4·h and 3 μm, in comparison with 0.1 mg2/cm4·h and 28 μm of the substrate after high temperature oxidation after 100 h. At higher temperature 1073 K, the composite coating also apparently improves the oxidation resistance (0.03 mg2/cm4·h) compared with the non-coated substrate (7.95 mg2/cm4·h). It was observed outward oxidation at 1073 K for the composite coating by XRD and SEM-EDS analysis, which is due to the fact that Ti diffused towards the coating surface and formed Al2TiO5. Finally, the oxidation resistance mechanism was discussed. The overall diffusion coefficient is reduced by the formation of the α-Al2O3 layer. And the oxidation is inhibited by reducing substrate surface oxygen partial pressure by composite coating.

    更新日期:2017-09-20
  • Glass shell etching to control residual quenching stress in Co-rich amorphous ferromagnetic microwires
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    V.A. Bautin, E.V. Kostitsyna, A.V. Popova, S.A. Gudoshnikov, A.S. Ignatov, N.A. Usov

    The magnetic properties of amorphous glass coated microwires are determined mainly by the distribution of residual quenching stresses over the microwire cross section. In this paper a control of the residual quenching stresses in amorphous ferromagnetic microwires is achieved by changing the microwire glass shell thickness by etching. To this end, a special gel is synthesized for precision glass shell etching of series of Co-rich microwires. The use of the gel provides a possibility of uniform etching of the microwire glass coating at a rate of 0.2–3.2 μm/h depending on the amount of glass already removed, a surface roughness being about 40–100 nm. It is also possible to completely remove the glass shell of the microwire without damage its metallic nucleus. The small angle magnetization rotation method has been used to determine the change in the amplitude of the residual quenching stress with a gradual decrease of the glass shell thickness of microwires of composition Co67Fe4Ni2Mo2B11Si14 and Co71Fe4Si10B15. It is found that the amplitude of the residual quenching stress deceases by 40–50% in average after removing of the layer of 1 μm thickness from the glass coating.

    更新日期:2017-09-20
  • Facile preparation of flower-like NiMn layered double hydroxide/reduced graphene oxide microsphere composite for high-performance asymmetric supercapacitors
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Long Huang, Bingchuan Liu, Huijie Hou, Longsheng Wu, Xiaolei Zhu, Jingping Hu, Jiakuan Yang
    更新日期:2017-09-20
  • Correlation between vibrational modes of A-site ions and microwave dielectric properties in (1−x) CaTiO3−x (Li0.5Sm0.5)TiO3 ceramics
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Fanfan Ning, Lin Gan, Shifeng Yuan, Zeming Qi, Juan Jiang, Tianjin Zhang

    (1-x)CaTiO3-x(Li0.5Sm0.5)TiO3 (0.7 ≤ x ≤ 0.8, CLST) ceramics with an orthorhombic perovskite structure were fabricated by a conventional solid-state reaction method. The effects of composition variation on the microwave dielectric properties were studied in detail. The permittivity (εr) and quality factor (Q × f) value decreased with an increase in the x value, and the temperature coefficient of the resonant frequency (τf) reached nearly zero. Raman and infrared reflection spectroscopy were employed to reveal the relationship between vibrational modes and microwave dielectric properties. The Raman spectra fitted with the Lorentzian model indicated that the dielectric loss deteriorates with an increase in the x value are the result of the lowered A-site cation ordering degree. The harmonic oscillator model was used to fit the infrared reflection spectra, and the obtained complex dielectric response was extrapolated down to the microwave region. The infrared reflection spectra show that the vibrational modes related to A-site cations at lower frequencies (i.e., <150 cm−1) play the most important role in the microwave dielectric properties of CLST ceramics. The optimal microwave dielectric properties were found to be εr = 109.4, Q × f = 4698 GHz, and τf = 1.6 ppm/°C in the sample of 0.22CaTiO3-0.78(Li0.5Sm0.5)TiO3.

    更新日期:2017-09-20
  • Flexural properties of chemical vapor deposited zinc sulfide at high temperatures
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Tianbao Cheng, Yongbin Ma, Huimin Li, Daining Fang, Yazheng Yang

    The flexural properties of chemical vapor deposited (CVD) zinc sulfide (ZnS) above 600 °C are studied for the first time. The bending strength increases up to 600 °C and then decreases rapidly. The Young's modulus initially decreases, reaches the minimum value near 900 °C, and then increases as temperature increases. Recrystallization occurring above 800 °C will reduce the strength and enhance the stiffness. Phase transformation at 1000 °C will increase both strength and stiffness. CVD ZnS shows completely linear deformation behavior below 800 °C. Nonlinearity occurs when temperature is greater than 800 °C and increases significantly as temperature or holding time increases because of recrystallization. The mechanisms being responsible for the aforesaid mechanical behavior are expounded by macro and micro analysis. The direct evidence for recrystallization of CVD ZnS at high temperatures is observed.

    更新日期:2017-09-20
  • Interaction between CdS nanocrystals and PVP leading to co-operative growth of CdS-PVP nanocomposites: A Raman and AFM mapping study
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Ekta Rani, Alka A. Ingale, A.K. Sinha

    CdS-PVP nanocomposites grown with various concentrations of Cd+/S− and PVP are studied using Raman and atomic force microscopy mapping on same selected areas. The study shows that CdS nanocrystals are embedded in either a thin-film or spheres of PVP, formation of which depends on relative ratio of Cd+/S− concentration (density of nanocrystals) to PVP. Collapse of PVP from planer matrix to the sphere morphology is correlated with high density of CdS nanocrystals and the attractive interaction between CdS nanocrystals and PVP polymer leading to a co-operative growth mechanism. The understanding developed can be used to control the growth of CdS-PVP nanocomposites with desired properties for optoelectronic device applications.

    更新日期:2017-09-20
  • Facile synthesis of ZnO nanoparticles on carol-like Cu2O nanowires for photoelectrochemical hydrogen generation
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Ying-Chu Chen, Yu-Chen Chang, Yu-Kuei Hsu

    A simple chemical route is utilized to decorate ZnO nanoparticles (NP) on the coral-like Cu2O nanowires (NW) surface as a p-n heterojunction photocathode for photoelectrochemical (PEC) hydrogen production. The SEM and TEM results confirm the morphology and structure of coral-like Cu2O NW/ZnO NP nanocomposite; meanwhile, the EDS and XPS results display the chemical binding and composition of Cu2O and ZnO materials. Electrochemical impedance measurements demonstrate that the coral-like Cu2O NW/ZnO NP achieves fast charge transfer. Notably, the p-Cu2O NW/n-ZnO NP photocathode can achieve the highest photocurrent of −3.4 mAcm−2 and its IPCE values significantly show the 1.5-fold enhancement compared to pristine p-Cu2O NW, ascribing the efficient separation efficiency of photogenerated electron-hole pairs and greater PEC activity.

    更新日期:2017-09-20
  • Continuously tunable organic solid-state laser based on the adjustment of effective refractive index
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-20
    Yajie Feng, Xiaolei Yu, Rui Zhang, Jianwei Wu, Peng Zhang, Shijian Chen, Dingke Zhang
    更新日期:2017-09-20
  • Microstructure evolution, damping capacities and mechanical properties of novel Mg-xAl-0.5Ce (wt.%) damping alloys
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Jingfeng Wang, Shun Li, Zhongshan Wu, Haibo Wang, Shiqing Gao, Fusheng Pan

    The effect of Al content on the microstructure, damping behavior and mechanical properties of Mg-xAl-0.5Ce (wt%) damping alloys was systematically studied. Al content had a great effect on the morphology features of Al4Ce phases. The quasi-rectangular network structure was observed in as-cast Mg-1Al-0.5Ce alloy. The Al addition promoted the dynamic recrystallization during extrusion process and led to the texture weakening, but the basal texture was sharpened with further Al addition due to the consumption of the Ce solute. The as-extruded Mg-1Al-0.5Ce alloy showed the best damping capacity among as-extruded Mg-xAl-0.5Ce alloys, which was mainly ascribed to the texture weakening. The ductility was improved with increasing Al content, while the strength was reduced. This behavior was related with the texture weakening and increasing grain sizes. The as-extruded Mg-1Al-0.5Ce alloy exhibited the excellent comprehensive performance. The peak P2 of as-extruded alloys in the first heating run was a superimposed peak, consisting of a grain boundary relaxation peak and a recrystallization peak. The grain boundary peaks P2 in the second heating run shifted to lower temperatures and their activation energies decreased with increasing Al content. The reasons for the variation of the grain boundary peak P2 were discussed.

    更新日期:2017-09-20
  • Effect of alpha-particles irradiation on the phase evolution and chemical stability of Nd-doped zircon ceramics
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Yi Ding, Zhengdi Jiang, Yanjun Li, Hui Dan, Xirui Lu, Yushan Yang, Tao Duan

    Zircon, ZrSiO4, has a structure that can incorporate actinides. Therefore, the susceptibility of the zircon structure to irradiation damage has been investigated by accelerated irradiation experiments. Synthetic Zr1−xNdxSiO4−x/2 (x = 0, 0.01, 0.10) ceramics were irradiated with 0.5 MeV 4He2+ ions (fluences 1 × 1014 to 1 × 1017 ions/cm2) at room temperature. The irradiation effects on phase structure and chemical stability of the ceramics were investigated. It is found that the main crystal structure is maintained, however, little amorphization is leaded as a result of intensified irradiation. Raman spectra reveal that the main peaks slightly broaden and weakened with increasing fluence, indicating little amorphization has been induced by irradiation. The irradiation resistance is enhanced by the growing neodymium content. Moreover, microtopography and element distribution have no changed even after irradiation. Although the LRNd increases slightly with increasing Nd loading and irradiation, the excellent chemical stability (∼10−4 g m−2 d−1) is maintained.

    更新日期:2017-09-20
  • Influence of oxygen partial pressure adopted in separate heat-treatment steps on the epitaxy of LZO film
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Yao Wang, Chengshan Li, Jianqing Feng, Lihua Jin, Zeming Yu, Pingxiang Zhang

    The influence of oxygen partial pressure on epitaxy is systematically studied in La2Zr2O7 (LZO) thin films fabricated by metal organic deposition (MOD) on yttria stabilized zirconia (00l) single crystal substrates. The results show that oxygen partial pressure affects not only the epitaxial growth but also the morphology evolution of film. It is observed that the texture sharpness of LZO film improves while its surface flatness becomes worse with increasing oxygen partial pressure during the whole heat-treatment process. Further studies illustrate that high oxygen partial pressure at pyrolysis step favors the texture sharpening of LZO film, which is contributed to the complete decomposition of organic constitution and the decrease of residual carbon in oxide film. However, low oxygen partial pressure at crystalline step helps the improvement of surface flatness for LZO thin film. It is supposed to be linked with the decrease of oxygen vacancy defects and the increase of grain size along with the replenishment of oxygen content at the crystallization stage. Tailoring oxygen partial pressure at separate heat-treatment steps is important to improving texture sharpness and surface flatness of LZO buffer film as long as the oxidation of metallic substrate can be avoided in coated conductors.

    更新日期:2017-09-20
  • Microstructure and mechanical properties of as-cast Mg-Sn-Zn-Y alloys
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Yu'an Chen, Yi Wang, Junjie Gao

    The effects of yttrium(Y) addition on the microstructure and mechanical properties of the as-cast Mg-5Sn-3Zn have been investigated. Results indicate that the addition of Y to Mg-5Sn-3Zn not only refines the grains but also promotes the precipitation of MgSnY phase with high stability. An increase addition of Y form 0.2–0.8 wt% increases the amount and size of MgSnY which would influence the mechanical properties of the as-cast alloys. The precipitation behavior of Mg2Sn and MgZn2 was also discussed. It was found that the MgZn2 phase is tend to precipitates attach to the Mg2Sn phase because the mismatch degree between them is relatively low, which have some guiding role in increase the amount of MgZn2 by Sn addition to enhance the performance of Mg-Sn-Zn alloys. In addition, Y to the Mg-5Sn-3Zn alloy general improves the mechanical properties but over does of Y would make it decrease, especially the elongation, which is affected by the grains and precipitates, improved significantly. The addition of 0.5 wt% Y gives the alloy favorable properties that the ultimate tensile strength reaches to 229 MPa and the elongation peaks at 19.2% at room temperature.

    更新日期:2017-09-20
  • Enhancing creep resistance of SnBi solder alloy with non-reactive nano fillers: A study using nanoindentation
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Lu Shen, Asta Qili Foo, Shijie Wang, Zhong Chen

    With excellent performance in mechanical strength and hardness, low melting point solder alloys have been identified as a promising lead-free alternative for microelectronic industry. However, the application of such alloys is hindered because of the serious creep deformation when electronic devices are inevitably heated up during operation or even at room temperature. In this study, non-reactive Al2O3 nano particles is explored as an option to enhance the creep resistance of eutectic SnBi alloy that has a melting temperature at 139 °C. Eutectic SnBi was mixed with nano Al2O3 particles for up to 4 wt%. Nanoindentation testing protocol for the creep properties measurement is used in this study. Core diffusion controlled dislocation climb is found to be the creep mechanism for the composite alloy. Other mechanical properties including elastic modulus and hardness are also evaluated and related to the microstructure evolvement of the nanocomposite alloy at various filler loadings. This work also compares the effectiveness of non-reactive fillers with the reactive fillers on enhancing the creep resistance of SnBi alloy. Suitable filler candidates for the best mechanical performance of SnBi composite alloys are recommended.

    更新日期:2017-09-20
  • Electrical conductivity tuning and valence band splitting studies in Copper Gallium Selenide thin films
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Anitha Abraham, K. Keerthi, S. Shaji, Uday Deshpande, Rachel Reena Philip

    Copper gallium selenide (CGS) semiconductor thin films are suitable for various optoelectronic devices due to their stoichiometry dependent properties. Tuning of electrical conductivity (0.5–90 S/cm) by compositional variations of CGS thin films prepared by reactive evaporation of the three elements under vacuum is presented here. This p-type absorber material withstands its conductivity type over the entire range of compositional variation. The structure, morphology, elemental composition, chemical states, electrical and optical properties of the thin films are characterized using techniques like X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, UV–visible absorption spectroscopy and Hall effect measurements. Optical studies of the films reveal a three-fold absorption from which crystal field splitting ∼0.06 eV and spin orbit splitting ∼0.09–0.17 eV are determined. The optical fundamental absorption edges of the films vary from 1.6 to 1.67 eV.

    更新日期:2017-09-20
  • Structural impact of chromium incorporation in as-grown and flash-lamp-annealed sputter deposited titanium oxide films
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    R. Gago, S. Prucnal, R. Pérez-Casero, I. Caretti, I. Jiménez, F. Lungwitz, S. Cornelius

    We address the impact of chromium (Cr) incorporation (<15 at.%) in the structure of titanium dioxide (TiO2:Cr) films for as-grown and after flash-lamp-annealing (FLA) states. Samples were produced by DC magnetron sputtering on either unheated or heated (400 °C) substrates. Complementary medium- and local-order information was extracted by X-ray diffraction and absorption near-edge structure, respectively. TiO2:Cr grown on unheated substrates are amorphous with the major contribution from Cr3+ and progressive formation of Cr6+ with Cr. On heated substrates, anatase phase is dominant for low Cr levels (≤7 at.%) and the structure evolves with Cr towards a disordered mixed-oxide with rutile structure. By tuning the FLA energy density, customized (single or mixed) phase formation is achieved from (initially amorphous) Cr-free TiO2. For amorphous TiO2:Cr with low Cr (≤7 at.%), FLA induces a short-range rutile structure but structural ordering is not observed at higher Cr levels. Nonetheless, FLA annihilates Cr6+ sites and promotes Cr4+, which is associated to the mixed-oxide rutile. FLA also improves the pristine structure of anatase TiO2:Cr grown on heated substrates. These results provide relevant information about the atomic structure of mixed oxides and the use of FLA for the synthesis of band-gap engineered TiO2-based materials.

    更新日期:2017-09-19
  • Investigation of NiAl intermetallic compound as bond coat for thermal barrier coatings on Mg alloy
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Xizhi Fan, Ling Zhu, Wenzhi Huang

    Bond coats play a significant role in manipulating the stability of 8YSZ thermal barrier coatings (TBCs) deposited on Mg alloy. In this study, the metal of Ni-Al mixture was sprayed as bond coat via reaction plasma spraying (RPS). Besides, Intermetallic compound NiAl was prepared by self-propagating high-temperature synthesis (SHS). The pure intermetallic compound NiAl was sprayed as bond coat via atmospheric plasma spraying (APS). The microstructure, composition, bond stability and corrosion resistance of the produced bond coats were investigated to find the optimal bond coat for the TBCs on Mg alloy. Results indicate that the bond coats composed of NiAl show excellent bond stability. High toughness of the RPS Ni-Al bond coat results in high tensile bond strength. The APS NiAl bond coat leads to outstanding thermal shock resistance mainly attributing to its moderate thermal expansion match, good mechanical properties and excellent corrosion resistance.

    更新日期:2017-09-19
  • Ternary-component reduced graphene oxide aerogel constructed by g-C3N4/BiOBr heterojunction and graphene oxide with enhanced photocatalytic performance
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Xue Yu, Peiwen Wu, Caixia Qi, Junjie Shi, Lijuan Feng, Chunhu Li, Liang Wang
    更新日期:2017-09-19
  • CeO2/CNTs hybrid with high performance as electrode materials for supercapacitor
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Yang Luo, Tianye Yang, Qi Zhao, Mingzhe Zhang

    Combination of CeO2 chunks and carbon nanotubes (CNTs) as supercapacitor electrode material is fabricated. Superior electrochemical performance including high specific capacitance and long term cycling stability is exhibited through electrochemical tests; the CeO2/CNTs electrode achieves specific capacitance reaching 818 F g−1 at scan rate of 1 mV s−1. The hybrid displays excellent capacitance retention of 95.3% after 2000 cycles. The electrochemical property is attributed to the redox properties, good electrical conductivity and synergistic effect of two materials. With the Schottky barrier at CeO2/CNTs interface, electrons can be accumulated at the Fermi level. More electrons can be released in the process of discharge. It is demonstrated that this kind of nanocomposites could be a promising candidate as electrode material for supercapacitor applications.

    更新日期:2017-09-19
  • Mechanical behaviour of brushite and hydroxyapatite coatings electrodeposited on newly developed FeMnSiPd alloys
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    J. Fornell, Y.P. Feng, E. Pellicer, S. Suriñach, M.D. Baró, J. Sort
    更新日期:2017-09-19
  • Ultrafine-grained Ti-40Nb prepared by reactive milling of the elements in hydrogen
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Inge Lindemann, Romy Schmidt, Stefan Pilz, Bernhard Gebel, Angelika Teresiak, Annett Gebert

    Powder metallurgical processing of β-type Ti alloys is an emerging approach for the production of compact or porous materials for bone implant applications which combine very low stiffness with suitable strength. Significant strength enhancement can be expected when ultrafine-grained material states are achieved in consequence of employing nanocrystalline starting materials for the powder compaction process. In the present study it is demonstrated that nanocrystalline (Ti,Nb)H2 with fcc CaF2 type crystal structure (Fm-3m) can be obtained via reactive milling of Ti and Nb in hydrogen atmosphere. (Ti0.75Nb0.25)H2 contains 3.2 wt% hydrogen which is completely desorbed below 700 °C in three steps. Thermal desorption treatment of the as-prepared nanocrystalline hydride powder leads to the formation of ultrafine-grained β-type Ti40Nb.

    更新日期:2017-09-19
  • Transparent NiO/ZnO heterojunction for ultra-performing zero-bias ultraviolet photodetector on plastic substrate
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Malkeshkumar Patel, Joondong Kim

    All transparent photoelectric devices were achieved for the highly-performing photodetectors. The high transparent heterojunction photodetector of the configuration of NiO/ZnO/ITO/PET was realized by using the solid-state sputtering method. All metal oxide layers were formed at room temperature to be applied on the plastic substrate. The ITO layer was directly coated on the PET substrate to work as a transparent conductor. To form the transparent p/n junction, p-type NiO was reactively sputtered following by n-type ZnO deposition onto the ITO. This high visible-range transparent (74.8%) photodetector is extremely sensitive to detect the tiny UV light density of 10 μW/cm2 with the ultra-fast photoresponse time (19 μs) and high-photoresponse ratio (1944) due to the merit of excitonic absorption. The design scheme of zero-bias operating transparent heterojunction can be applied for visible electronic devices and solar cells.

    更新日期:2017-09-19
  • Interfacial bonding mechanism and mechanical properties of novel AZ31/WE43 bimetal composites fabricated by insert molding method
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    K.N. Zhao, H.X. Li, J.R. Luo, Y.J. Liu, Q. Du, J.S. Zhang

    AZ31/WE43 bimetal composites are prepared by insert molding method, and the microstructure evolution, phase constitution and bonding strength at the interface are investigated. A relatively uniform transition interface with a thickness of 50 to 150 μm is formed, indicating a good metallurgical bonding. The analysis shows the transition interface is mainly composed of lamellar-like and particulate Al2RE phase, particulate Al3Zr phase on AZ31 side, a precipitation free zone (PFZ) in the middle and quadrate-like Y-rich phases congregated together at the grain boundary close to WE43 side. The average interface shear strength is 108 MPa, which is much superior to other bimetal composites reported so far. The fracture analysis indicates that during the shear tests, the cracks initiates from the weak zone of casting AZ31 alloy. Aided by the interface microstructure, the mechanism on interface bonding is further discussed.

    更新日期:2017-09-19
  • Ceria coating for controlling the isothermal oxidation behavior of Ni-based alloy 625
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Xu Wang, Jerzy A. Szpunar

    A ceria coating is electro-deposited on a chromium oxide forming Ni-based alloy to investigate the mechanisms of the reactive element effects. It is demonstrated that the ceria coating not only improves the oxidation resistance but also enhances the adherence between the oxide layer and the substrate alloy. The formation of iron oxide results in porous and cracked oxide layers on the bare sample. Oxide spallation starts to occur on the bare sample after exposure at 900 °C for 500 h. In contrast, a mixed iron-free oxide layer forms on the coated sample which is believed to enhance the oxidation resistance of the substrate. The change in oxidation mechanism of the coated sample from outward diffusion to inward diffusion is attributed to grain-boundary segregation of ceria particles. Furthermore, the formation of fine oxide grains on the coated sample improves the adhesion between the oxide layer and the matrix alloy. Schematic models of the oxidation mechanism are developed to interpret the oxidation behaviour of the bare and coated samples.

    更新日期:2017-09-19
  • Influence of MoO3 on boron aluminosilicate glass-ceramic coating for enhancing titanium high-temperature oxidation resistance
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Fang Yu, Dongguang Gu, Yifeng Zheng, Yali Luo, Xueyan Li, Han Chen, Lucun Guo

    The anti-oxidation behavior of boron aluminosilicate glass-ceramic materials with different MoO3 content deposited on titanium in temperatures range 850–1050 °C were investigated. The experimental results showed that in comparison with the bare titanium, the weight gain of specimen without MoO3 decreased from 18.7 to 0.6 mg/cm2 after 100 h oxidation at 850 °C.The addition of MoO3 was able to provide further decrease on the oxidation rate of titanium from 0.6 to 0.1 mg/cm2. The 20 wt.% MoO3 system measured the least weight gain and maximum tensile strength which was between the substrate and the coating for 30.1 MPa at 850 °C for 100 h whilst led to the peak retained strength value with 8.7 MPa after 30 times thermal cycles to 700 °C. The EDS line scanning images revealed that a molybdenum rich interlayer was detected in between the substrate and coating layer with average width of about 2 μm and it was believed that it did play an essential part in blocking the inward diffusion of oxygen to titanium.

    更新日期:2017-09-19
  • Improved electrode materials for Li-ion batteries using microscale and sub-micrometer scale porous materials - A review
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    M.K. Shobana, Yunsung Kim

    In this paper, we review the challenges and opportunities for foam materials and their composites as novel energy conversion materials. Specifically, foams with an exceptionally high specific surface area could be a perfect solution for advanced energy applications because the electrodes with limited reaction area between an electrolyte and an active material have been identified as one of the key factors affecting the low-level performance of Li-ion batteries, which is a major challenge hindering their commercial application. In the past decade, several electrode materials, structures, and fabrication processes have been developed and investigated with the intention of improving electrode performance. Among these processes, foam architecture is attractive as an electrode structure in Li-ion batteries as it has an intrinsic structural integrity with the ability to buffer stress caused by the large volume changes in high capacity anode materials during cycling. In this review, the electrochemical properties, reversible capacity, long cycle capability, high discharge capacity, battery lifetime, power density, energy efficiency, tensile strength, and mechanical properties of various foam electrode materials are discussed. The foremost objective of this review is to provide an overview on the latest research on improved electrode performance and current perspectives on porous electrode materials for future Li-ion batteries.

    更新日期:2017-09-19
  • The influence of cathodic protection potential on the biofilm formation and corrosion behaviour of an X70 steel pipeline in sulfate reducing bacteria media
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Tao Liu, Y. Frank Cheng

    This work investigated the biofilm formation and microbiologically influenced corrosion (MIC) of a pipeline steel under cathodic protection (CP) in an extracted soil in solution with addition of sulfate reducing bacteria (SRB), Desulfovibrio desulfuricans. It was found that the application of CP did not affect the planktonic bacterial growth in the solution. The CP facilitated the bacterial attachment to the steel in this system, and a layer of biofilm formed on the cathodically protected steel, decreasing the CP effectiveness for corrosion protection. The CP potential of −850 mV vs. copper sulfate electrode (CSE) was not sufficient to protect the steel from corrosion in SRB containing media. Despite a further negative shift of the CP potential to −1000 mV vs. CSE was effective to control uniform corrosion of the steel, pitting corrosion still occurred under biofilm on the steel.

    更新日期:2017-09-19
  • Effects of HIP on microstructural heterogeneity, defect distribution and mechanical properties of additively manufactured EBM Ti-48Al-2Cr-2Nb
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Mohsen Seifi, Ayman A. Salem, Dan P. Satko, Ulf Ackelid, S. Lee Semiatin, John J. Lewandowski

    The present work was conducted to establish an initial understanding of the processing-microstructure-property relations for γ-TiAl manufactured by electron beam powder bed fusion. The investigation included microstructure characterization at different length scales of near-γ titanium aluminide Ti-48Al-2Cr-2Nb (in atom pct) in addition to evaluating the compressive strength, microstructures, fracture toughness, and fatigue crack growth behavior. Micro-CT revealed significant variations in the spatial distribution of internal defects along the build of the as-deposited sample, while HIP reduced these defects. However, inhomogeneous microstructures were exhibited in both the as-deposited and HIP materials while HIP processing reduced both the yield strength and amount of scatter in mechanical properties. Despite these observations, fracture toughness and fatigue crack growth results were in the range of those reported for conventionally cast material. The use of cloud computing provided an efficient means for data management, microstructure analytics, and collaboration among various contributors to the work.

    更新日期:2017-09-19
  • White-light long persistent luminescence of Tb3+-doped Y3Al2Ga3O12 phosphor
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Shaoan Zhang, Zhongfei Mu, Yang Lv, Liumin Fan, Yang Li, Guifang Ju, Yihua Hu

    A novel white long persistent phosphor of Y3Al2Ga3O12:Tb3+ was prepared by the soft chemical method. Y3Al2Ga3O12:Tb3+ presented a white long persistent luminescence when the doping concentration of Tb3+ was just 0.1% and the afterglow time was able to last more than 2 h. The persistent emission of Tb3+ in Y3Al2Ga3O12 consisted of all color emissions in the visible spectrum from an identical luminescent center (Tb3+); meanwhile, the white-light color won't vary as the afterglow time goes on. The mystery behind this phenomenon was studied deeply including trap depths, distribution and types. The trap depths was calculated from 0.65 to 1.15 eV by the initial rise method analysis, highly corresponding to the ideal energy for trapping and releasing at room temperature. What's more, the estimated trap structure was proved to be a continuous trap distribution by varying the thermal cleaning temperature. The persistent luminescence mechanism of Y3Al2Ga3O12:Tb3+ was illustrated and discussed in detail on the basis of the experimental results. This work provides a promising approach for the development of white long persistent phosphor.

    更新日期:2017-09-19
  • Solid solution and densification behavior of zirconium oxycarbide (ZrCxOy) ceramics via doping ZrO2 and Zr in ZrC
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Hu-Lin Liu, Zhen-Yong Man, Ji-Xuan Liu, Xin-Gang Wang, Guo-Jun Zhang

    zirconium oxycarbide (ZrCxOy) ceramics were hot pressed using ZrC-5ZrO2 and ZrC-5ZrO2-5Zr (number in mol%) mixtures as starting powders, and the solid solution and densification processes were investigated. When 5 mol% ZrO2 were added to ZrC matrix, ZrCxOy and CO were formed during the reaction between ZrC and ZrO2 occurred above 1600 °C. And the sintered ZrCxOy ceramic had numerous pores. However, the co-doping of ZrO2 and Zr could reduce the reaction temperatures and CO amounts in ZrC-5ZrO2-5Zr system, resulting in a near fully dense ZrCxOy ceramic. The chemical composition of obtained ZrCxOy ceramics were also calculated according to oxygen content and reaction processes.

    更新日期:2017-09-19
  • High temperature oxidation behaviors of equimolar NbTiZrV and NbTiZrCr refractory complex concentrated alloys (RCCAs)
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    T.M. Butler, K.J. Chaput, J.R. Dietrich, O.N. Senkov
    更新日期:2017-09-19
  • Evolution of structural and optical properties of Ag implanted CrN thin films with annealing temperature
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    M. Novaković, M. Popović, E. Schmidt, P. Schöppe, M. Mitrić, N. Bibić, C. Ronning, Z. Rakočević

    This study reports on the changes of the structural and optical properties occurring in CrN thin films upon Ag ion implantation. The films were grown by reactive sputtering on top of Si (100) wafers at a temperature of around 150 °C. Subsequently, the films were implanted with Ag ion fluences in the range of 0.5 × 1016 ions/cm2 ‒ 2 × 1016 ions/cm2 with energy of 200 keV. The structural and morphological changes, promoted by in-vacuum annealing of the as-implanted thin films at 200 °C, 400 °C and 700 °C, resulted in different optical responses of the CrN:Ag films due to the formation of Ag nanoparticles. The nanoparticles were inhomogenously distributed through the layer, which is related to the implantation distribution of silver in CrN. Apart from this, Ag nanoparticles with a size of 20–25 nm were formed at the surface of the layer. These structural properties are responsible for the formation of a broad optical absorption peak. This peak is located at ∼420 nm and can be associated with the plasmon resonance of Ag particles embedded in the CrN matrix.

    更新日期:2017-09-19
  • A combined experimental and theoretical investigation of the Al-Melamine reactive milling system: A mechanistic study towards AlN-based ceramics
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-19
    Seyyed Amin Rounaghi, Danny E.P. Vanpoucke, Hossein Eshghi, Sergio Scudino, Elaheh Esmaeili, Steffen Oswald, Jürgen Eckert
    更新日期:2017-09-19
  • 更新日期:2017-09-19
  • Impact of the crystal electric field on magnetocaloric properties of CsGd(MoO4)2
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-18
    V. Tkáč, A. Orendáčová, R. Tarasenko, M. Orendáč, A. Feher

    Magnetocaloric effect (MCE) was investigated in the single crystal of CsGd(MoO4)2 in the temperature range from 2 to 30 K and fields up to 5 T applied along the easy and hard magnetic axis. The analysis of specific heat and magnetization provided the refinement of crystal electric field (CEF) parameters supporting the dominance of uniaxial symmetry. The knowledge of CEF energy levels enabled the extrapolation of MCE parameters outside the experimental region. Consequently, maximum values of the isothermal entropy change, −ΔSM, in magnetic fields up to 5 T are expected to occur at temperatures between 1 and 2 K. While −ΔSM achieves 19.2 J/kgK already for the field 1 T, for the field change 7 T, maximal −ΔSM≈ ≈ 26.8 J/kgK with a refrigerant capacity of 215 J/kg is expected. The absence of thermal hysteresis and the losses due to eddy currents as well as good chemical stability makes the compound CsGd(MoO4)2 attractive for magnetic refrigeration at low temperatures. The possibilities of further enhancement of MCE parameters are discussed.

    更新日期:2017-09-19
  • Alignment of Ag nanowires on glass sheet by dip-coating technique
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-18
    Jinyang Feng, Huida Xia, Fangfang You, Haibo Mao, Xiao Ma, Haizheng Tao, Xiujian Zhao, Moo-Chin Wang

    Thin film with highly-oriented Ag nanowires on glass surface was prepared by a dip-coating technique from a Polyvinylpyrrolidone/ethanol solution. Ag nanowires were firstly prepared by seed mediated method, and then dispersed in solution by mechanical and ultrasonic dispersion. The alignment of the Ag nanowires mainly depends on the concentration of the polyvinylpyrrolidone (PVP) and the pulling speed during dip-coating. It is observed that there is obvious optical polarizing performance in the 1400–1900 nm wavelength range. This approach is expected to offer a low-cost preparation method for large-scaled assembly of functional nanoscale electronic and photonic structures.

    更新日期:2017-09-19
  • Polycrystal plasticity simulation of extrusion of a magnesium alloy round bar: Effect of strain path non-uniformity
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-18
    Tao Tang, Yichuan Shao, Dayong Li, Liming Peng, Yinghong Peng, Shaorui Zhang, Peidong Wu

    A flow line model is established and combined with the crystal plasticity method to simulate the extrusion process of a magnesium alloy round bar, and investigate the effect of strain path non-uniformity on development of texture and microstructure in extrusion. A parametric flow line model is established to characterize the material flow corresponding to different strain paths in the extrusion chamber. The polycrystal plasticity method coupled with a phenomenological dynamic recrystallization model is employed to analyze the evolution of texture and microstructure accompanying the deformation. The texture of material deformed near the central extrusion area shows the typical ring fiber texture in the (0001) pole figure, while the basal poles of the material deformed in the side areas tend to rotate backward to the extrusion direction, resulting from an increase of the activities of twinning and slip systems. The more refined microstructure is obtained in the side areas due to the higher strain rate. The difference of mechanical properties between center and side areas of the extruded bar are numerically investigated by simulating tension and compression by using different extrusion textures. Side material shows more isotropic mechanical property than central material, and then less twinning is operative in compression.

    更新日期:2017-09-19
  • Tailored perovskite Li0.33La0.56TiO3 via an adipic acid-assisted solution process: A promising solid electrolyte for lithium batteries
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-18
    Hyun Jun Choi, So Young Kim, Min Kyung Gong, Hari Vignesh, Vanchiappan Aravindan, Young Gi Lee, Yun-Sung Lee
    更新日期:2017-09-19
  • Structural and mechanical properties of Zr1−x Mox thin films: From the nano-crystalline to the amorphous state
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-18
    A. Borroto, S. Bruyère, N. Thurieau, C. Gendarme, E. Jimenez-Piqué, J.J. Roa, J.F. Pierson, F. Mücklich, D. Horwat
    更新日期:2017-09-19
  • Influence of zinc doping on the photocatalytic activity of nanocrystalline SnO2 particles synthesized by the polyol method for enhanced degradation of organic dyes
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-18
    Wissem Ben Soltan, Salah Ammar, Céline Olivier, Thierry Toupance
    更新日期:2017-09-19
  • Electrocaloric effect in relaxor ferroelectric Ba(Ti1-xYx)O3-x/2 ceramics over a broad temperature range
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-18
    Y. Zhao, X.Q. Liu, J.W. Wu, S.Y. Wu, X.M. Chen

    Crystal structures, dielectric, ferroelectric properties and electrocaloric effects of hetero-valent substituted Ba(Ti1-xYx)O3-x/2 ceramics were studied in the present work. The polar space group of P4mm was adopted based on the Rietveld refinement at room temperature. The diffusivity of phase transition and relaxor behavior are both strengthened by the yttrium substitution. The maximal pyroelectric coefficient decreases, and the extent of corresponding temperature deviated from the dielectric peak temperature to higher temperature increases with increasing the yttrium content. The adiabatic temperature changes and isothermal entropy changes display the same tendencies as those of the pyroelectric coefficients. The Ba(Ti0.944Y0.056)O2.972 ceramic shows the largest adiabatic temperature change and largest isothermal entropy change among all compositions over a broad temperature range of 50 K. For individual composition, the value of pyroelectric coefficient decreases with increasing the magnitude of applied electric field, and the temperature of maximal pyroelectric coefficient deviates from the dielectric peak temperature to higher temperature. Therefore, the optimal electrocaloric temperature can be adjusted by the magnitude of electric field in relaxor ferroelectricity.

    更新日期:2017-09-19
  • Facile preparation of two-dimensional Bi2MoO6@Ag2MoO4 core-shell composite with enhanced visible light photocatalytic activity
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-18
    Zhongliao Wang, Yao Huo, Jinfeng Zhang, Cheng Lu, Kai Dai, Changhao Liang, Guangping Zhu
    更新日期:2017-09-19
  • Tuned thermoelectric transport properties of Co2.0Sb1.6Se2.4 and Co2.0Sb1.5M0.1Se2.4 (M=Zn, Sn): Compounds with high phonon scattering
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-18
    N. Karthikeyan, Sivaprasad Ghanta, Samiran Misra, G. Jaiganesh, Partha Pratim Jana, K. Sivakumar
    更新日期:2017-09-19
  • Channelized carbon nanofiber with uniform-dispersed GeO2 as anode for long-lifespan lithium-ion batteries
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-18
    Xia He, Yi Hu, Zhen Shen, Renzhong Chen, Keshi Wu, Zhongling Cheng, Xiang Wu Zhang, Peng Pan
    更新日期:2017-09-19
  • Fabrication of solution-processed nitrogen-doped niobium zinc tin oxide thin film transistors using ethanolamine additives
    J. Alloys Compd. (IF 3.133) Pub Date : 2017-09-18
    Jiann-Shing Jeng, Chi-Min Wu

    In this study, we fabricated the nitrogen-doped NbZnSnO channel layers by using the sol-gel method. Monoethanolamine (MEA) was used as a nitrogen additive. From the XPS results, the concentration of oxygen vacancies changes as a function of MEA/Nb ratio. A NbZnSnO film with MEA/Nb of 0.2 shows the lowest amount of oxygen vacancies. TFT electrical performance also shows a device with an MEA/Nb ratio of 0.2 possesses a high carrier mobility (7.4 cm2 V−1s−1) and good bias stress stability. In addition, we also investigated the effect of the aging time of precursor solution on the electrical characteristics of the TFT. After adding MEA, the annealing temperature of the NbZnSnO channels can be reduced, pertaining to the acceleration of the hydrolysis and condensation reaction.

    更新日期:2017-09-19
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
所有期刊列表A-Z