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  • Strongly canted antiferromagnetic ground state in Cu3(OH)2F4
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-15
    Igor L. Danilovich, Anna V. Merkulova, Igor V. Morozov, Evgeniy A. Ovchenkov, Felix M. Spiridonov, Elena A. Zvereva, Olga S. Volkova, Vladimir V. Mazurenko, Zlata V. Pchelkina, Alexander A. Tsirlin, Christian Balz, Stefan Holenstein, Hubertus Luetkens, Alexander A. Shakin, Alexander N. Vasiliev

    An unique crystal structure of copper hydroxyl-fluorite, Cu3(OH)2F4, hosts the trimerized chains of both edge-sharing and corner-sharing CuO2F2 plaquettes. The results of the comprehensive study of this compound, including new synthetic route, measurements of specific heat, ac- and dc-susceptibility, pulsed field magnetization, electron spin resonance, muon spin rotation and relaxation and first principles calculations are presented. The data evidence magnetic phase transition at TC = 12.5 K into canted antiferromagnetic state which is due to antisymmetric Dzyaloshinskii-Moriya (DM) exchange interaction. No alteration of DM component stemming from the intrinsic features of the crystal lattice in Cu3(OH)2F4 results in unusually large spontaneous magnetization. At T < TC, the remanence MR constitutes significant portion of saturation magnetization MS which defines the canting angle φ = 4°.

    更新日期:2018-10-15
  • Synthesis of hierarchical hollow urchin-like HGRs/MoS2/MnO2 composite and its excellent supercapacitor performance
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-15
    Zhixiao Chang, Xiuhong Zhu, Xin Ju, Xinghua Li, Xinliang Zheng, chunyan liao, Wenjing Zhang, Zhaoyu Ren

    Hierarchical hollow urchin-like ternary composite which consists of hollow graphene spheres(HGRs), flowerlike molybdenum disulfide(MoS2) and manganese dioxide(MnO2) nanoflakes has been successfully synthesized by chemical vapor deposition(CVD) and two-step hydrothermal methods. The HGRs/MoS2/MnO2 composite was characterized by X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM) and transmission electron microscopy(TEM), and its electrochemical properties were evaluated by cyclic voltammetry(CV), galvanostatic charge/discharge(GCD), and electrochemical impedance spectroscopy(EIS) measurements. The experimental results demonstrated that the specific capacitance of HGRs/MoS2/MnO2 composite is 608 F g−1 at a current density of 1 A·g−1, which is far higher than that of HGRs/MoS2 (300 F g−1) and HGRs/MnO2 (344 F g−1). In addition, 89.3% of the original capacitance of HGRs/MoS2/MnO2 composite is retained after 2500 cycles at a current density of 2 A·g−1, which keeps better cycle stability compared to HGRs/MnO2 composite. The excellent electrochemical performance can be ascribed to the synergistic effect of HGRs, flowerlike MoS2 and MnO2 nanoflakes. Flowerlike MoS2 as an ion buffer layer is beneficial to rapid ion diffusion and transportation from MnO2 into interior HGRs. Furthermore, HGRs/MoS2 composite as a three-dimensional(3D) matrix alleviates the volume change during charge/discharge cyclical process. The well-structured HGRs/MoS2/MnO2 composite with high performance has a great potential for advanced supercapacitors(SCs) applications.

    更新日期:2018-10-15
  • Influence of BaZrO3 additive on the energy-storage properties of 0.775Na0.5Bi0.5TiO3-0.225BaSnO3 relaxor ferroelectrics
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-15
    Lei Zhang, Yongping Pu, Min Chen

    Dense (1-x)(0.775NBT-0.225BSN)-xBZ ternary ceramics were fabricated by solid state methods and their dielectric and ferroelectric properties were systematically investigated. XRD and Raman analysis indicate that the structure complexity and phase diffusion were enhanced in 0.775NBT-0.225BSN relaxor system with BZ addition. With increasing the contents of BZ, average grain size greatly decreases. Dielectric study shows that dispersive relaxor-like behavior was beginning to convert to diffusive phase transition when x ≥ 0.2. Along with increasing the BZ contents, the slop of P-E loops and the energy-loss can gradually decrease. When x = 0.2, both a high Wd of 2.08 J/cm3 and η of 88.8% were achieved, due to the slimer P-E loops, the high Pm (∼20 μC/cm2) and Eb (245 kV/cm). As a result, the ternary ceramics system may be a good candidate for energy-storage ceramics of NBT-based materials.

    更新日期:2018-10-15
  • Synthesis and characterization of Na-substituted LiMnPO4 as a cathode material for improved lithium ion batteries
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-15
    Redouan El Khalfaouy, Abdellah Addaou, Ali Laajeb, Ahmed Lahsini

    The present study, report the sodium (Na) substituted lithium (Li) in LiMnPO4/C structure as an active material for lithium-ion batteries, and its effect on structure, morphology and electrochemical performances. Sodium with different concentrations has been substituted in the LiMnPO4 system using the solution combustion method. The XRD analysis confirmed a pure orthorhombic structure well indexed, which confirms a good substitution of Li+ ions by Na+. A maximum discharge capacity of 136.7 mAh g−1 was achieved for Li0.97Na0.03MnPO4/C composite cathode material compared to LiMnPO4/C (126.9 mAh g−1) with a coulombic efficiency of 93.8% higher than that of LiMnPO4/C (82.3%). It can be observed that the irreversible loss of capacity has been reduced by adding sodium (x = 0.03) Li0.97Na0.03MnPO4/C compared to LiMnPO4/C. With remarkable stability achieved, for the three doped samples (x = 0.01, 0.03 and 0.05 compared to x = 0.00), during the charge/discharge process.

    更新日期:2018-10-15
  • Electromigration behaviors of Sn58%Bi solder containing Ag-coated MWCNTs with OSP surface finished PCB
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-15
    Jungsoo Kim, Kwang-Ho Jung, Jae-Ha Kim, Choong-Jae Lee, Seung-Boo Jung

    We investigated the effect of Ag-coated multi-walled carbon nanotubes (Ag-MWCNT) on the microstructures and electromigration behaviors of a Sn58%Bi solder and organic solderability preservative (OSP) surface finished on the FR-4 printed circuit board (PCB) joint under a current stress of 3000 A/cm2 at 100 °C. Electromigration of Ag-MWCNT Sn58%Bi composite solder was investigated by daisy-chain test-kit. Reaction layers formed at the anode side and cathode side of the Sn58%Bi solder joints consisted of three microstructures; Bi-rich layer, Sn-rich layer, and intermetallic compounds (IMCs, Cu6Sn5 and Cu3Sn). The Bi-rich layer was mainly formed at the anode side in the couple of the Sn58%Bi solder joint with various times of applying current stress. The Bi-rich layer of the Ag-MWCNT Sn58%Bi composite solder joint was approximately 2 times thinner than that of the Sn58%Bi solder joint because the Ag-MWCNT acts as a diffusion barrier. Also, the Cu6Sn5 and Cu3Sn IMCs that formed at the interface between the Ag-MWCNT Sn58%Bi composite solder joints were thinner than those of the Sn58%Bi solder joints. The time to failure (TTF) was longest at the 0.05% Ag-MWCNT Sn58%Bi composite solder joint. Therefore, Ag MWCNT is expected to improve the reliability of electromigration in the Sn58%Bi composite solder joint.

    更新日期:2018-10-15
  • First-principles study of elastic, electronic, and optical properties of α-TeO2 under pressure
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-15
    Sen Gao, Xian Zhang, Qingfeng Zeng, Shiyu Wang

    Crystalline α-TeO2 was investigated at ambient pressure using ab initio calculations. The effect of pressure on α-TeO2 was studied from 0 to 10 GPa. The lattice parameters and elastic constants calculated by LDA and GGA method at 0 GPa both agree with the available theoretical and experiment results. The elastic constants Cij, the bulk modulus B, the shear modulus G, Young's modulus E, and the ductile and brittle character (B/G) were calculated and examined in detail. It was found that the calculated universal anisotropy index indicated that α-TeO2 has anisotropy under 0 GPa, and with the pressure increases, its elastic anisotropy increases. Furthermore, from the mechanical stability criteria, it is show that the structure of tetragonal α-TeO2 is not stable above 5.1 GPa. Finally, the electronic and optical properties were also investigated, and the results show that, on increasing the external pressure, the energy bandgap increases, with the optical spectrum exhibiting anisotropy in the x and z directions and a small blue shift under pressure.

    更新日期:2018-10-15
  • The design and the preparation of mesoporous Ag3PO4 nanorod/SrFe12O19 hexagonal nanoflake heterostructure for excellent microwave absorption
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Jieyi Yu, Jiahao Yu, Tongpan Ying, Caiyun Cui, Yuping Sun, Xianguo Liu

    Due to the high cut-off frequency induced by strong magneto-crystalline anisotropy, M-type strontium ferrite has been commercially used in GHz frequency. However, M-type strontium ferrite is unable to meet the performance requirements (strong absorption ability, thin absorbing thickness and broad effective bandwidth) of advanced absorbing materials. In order to overcome the above defects, mesoporous Ag3PO4 nanorods/SrFe12O19 hexagonal nanoflake heterostructure has been designed and prepared in this work. Being evaluated as microwave absorbents, this heterostructure exhibits the superior EM absorbing performances, such as the optimal reflection loss value of −63. 18 GHz at 5.1 mm, effective absorption bandwidth of 6.24 GHz at 2.3 mm and the EM absorption efficiency of 46.45 dB GHz/mm at 2.0 mm. The theoretical simulations are applied to explain the EM loss sources through the adjustment of frequency. This work provides a strategy to design effective microwave absorbers based on the dielectric-magnetic heterostructure from two aspects of theoretical simulation and experimental testing.

    更新日期:2018-10-14
  • Facile synthesis of mesoporous TiC-C nanocomposite microsphere efficient for hydrogen evolution
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Yujie Wang, Hao Deng, Chenlu Ye, Kang Hu, Kai Yan

    Mesoporous TiC-C nanocomposite microspheres have been facilely and successfully synthesized by a soft-template assisted hydrothermal method. The as-obtained hollow TiC-C microspheres presented large surface area. The fabricated TiC-C microsphere worked as an efficient electrocatalyst, displaying much improved performance in the hydrogen evolution reaction in comparison with the commercial TiC catalyst. The TiC-C microsphere was also a good candidate support to load 5 wt% Pt, which exhibited much better performance and lower onset potential in comparison with the commercial 20 wt% Pt@C. Our findings suggest that synthesis of the microsphere structure may provide a great opportunity to improve catalytic properties for hydrogen evolution.

    更新日期:2018-10-14
  • Aluminothermic reduction of ZrSiO4 in the presence of carbon for in situ formation of Zr-based silicides/carbides composites
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    C.L. Yeh, G.T. Liou

    Aluminothermic reduction of ZrSiO4 in the presence of carbon was investigated in the SHS (self-propagating high-temperature synthesis) manner. PTFE was employed not only as a reaction promoter to ensure self-sustaining combustion and improve the reduction of ZrSiO4, but as a carburizing agent to take part in carbide formation. The combustion wave velocity and temperature increased with increasing PTFE content, but decreased with carbon. Based on a correlation between combustion temperature and velocity, the activation energy Ea = 180.4 kJ/mol was deduced for the PTFE-activated ZrSiO4/Al/C reaction. According to the XRD and EDS analyses, the phase composition of the synthesized product depended on the total amount of carbon. The SHS reaction produced Al2O3-added Zr-silicides (ZrSi2 and ZrSi)/carbides (ZrC and SiC) composites. With an increase in carbon, the dominate phase was transferred from silicides to carbides. A further increase in carbon led to in situ formation of the ZrC/SiC/Al2O3 composite. The study confirmed ZrSiO4 as a source for the production of zirconium silicides, ZrC, and SiC.

    更新日期:2018-10-14
  • Structural stability studies of single-phase Ce2Ni7-type and Gd2Co7-type isomerides with La0.6Nd0.15Mg0.25Ni3.5 compositions
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Yumeng Zhao, Wenfeng Wang, Shumin Han, Wei Guo, Yuan Li, Lu Zhang, Guochang Xu
    更新日期:2018-10-14
  • Magnetic and electrical transport properties of Ce5RhGe2
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Paweł Skornia, Józef Deniszczyk, Marcin Fijałkowski, Andrzej Ślebarski

    We report a comprehensive investigations of the electronic structure and magnetic properties for Ce5RhGe2, that crystallizes in orthorhombic Y2HfS5-type structure. This novel phase was found to be ferromagnetic-type with the Curie temperature TC of 11.5 K in coexistence with spin-glass-like phase, displayed in the magnetic H−T phase diagram. The resistivity and magnetic susceptibility data also exhibit characteristic features of spin fluctuations at temperatures higher than TC. A combined experimental and theoretical study based on x-ray photoelectron spectroscopy (XPS) data together with ab initio band structure calculations indicate a mixed valence of Ce ions due to strong hybridization between Ce 4f states and conduction band.

    更新日期:2018-10-14
  • Efficient solid-state and dual-mode photoluminescence of carbon-dots/NaLuF4 microcrystals for multifunctional applications
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Aihua Zhou, Feng Song, Weijing Yao, Yingdong Han, Feifei Song, Wei Wu, Chengguo Ming, Dandan Ju, Adnan Khan

    The carbon-dots/NaLuF4 microcrystals have been synthesized by the hydrothermal method and bright blue emission from carbon dots is observed in aqueous and solid state under 365 nm excitation. Self-quenching property of the carbon-dots/NaLuF4 microcrystals under solid state was deeply investigated, by changing the ratio of citric acid (CA) and ethylenediamine (DHE). The results indicate that the carbon dots can be effectively adsorbed and dispersed on the surface of NaLuF4 microcrystals, suppressing the aggregation of carbon dots. Furthermore, the upconversion luminescence can also be realized under 980 nm laser excitation. From the above observations, the carbon-dots/NaLuF4 microcrystals not only reveal emission property of carbon dots and NaLuF4, respectively, but also optimize the property of carbon dots. It provides a promising new strategy to prevent the carbon dots quenching in solid state and the carbon-dots/NaLuF4 microcrystals may have potential multi-applications in different fields including temperature sensing, solid-state display lighting as well as security inks.

    更新日期:2018-10-14
  • Super hard carbon microtubes derived from natural cotton for development of high performance titanium composites
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Kamyar Shirvanimoghaddam, Ehsan Ghasali, Amirhossein Pakseresht, S.M.R. Derakhshandeh, Masoud Alizadeh, Touradj Ebadzadeh, Minoo Naebe

    Super hard carbon microtubes derived from natural cotton are developed as a cost effective filler for composite applications. Two different carbon materials including synthesized carbon microtubes (CMT) and carbon nanotube (CNT) were used to produce titanium laminate composite via spark plasma sintering process. The sintering process was performed at 1200 °C for both Ti-CMT and Ti-CNT samples which led to the fully densified composites. The proposed mechanism confirmed by cross-sectional XRD investigation revealed formation of Titanium Carbide (TiC) between Ti layers as interfacial bonding phase. A significant improvement in bending strength (1273 ± 11 MPa) and hardness (537 ± 28 Vickers) of Ti-CMT composites was observed compared to titanium laminate and Ti-CNT composite. The results of current study demonstrate the considerable potential of inexpensive yet super hard carbon based material for various composite applications.

    更新日期:2018-10-14
  • Electric field and frequency dependent scaling behavior of dynamic hysteresis in relaxor-based ferroelectric 0.71Pb(Mg1/3Nb2/3)O3–0.29PbTiO3 single crystal
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Yang Zhang, Bangzuan Long, Yajie Wen, Zhongwu Zhang, Wenwu Cao

    The evolution of the dynamic hysteresis with electrical field amplitude (E0) and frequency (f) in the relaxor-based ferroelectric 0.71Pb(Mg1/3Nb2/3)O3–0.29PbTiO3 (PMN-29PT) single crystal has been investigated systematically. Our results showed that the electric field dependent scaling relationship in PMN-29PT single crystal can be divided to three regions, and the hysteresis area <A> follows the power law <A>∝fαE0β in the low and high E0 regions, but the power law is not obeyed in the intermediate region due to the complex collective contributions of 180° and non-180° domains. The frequency dependent scaling relationship can be separated into two regions, and presents a unique behavior when the field level E0 is equal or lower than the coercive field Ec. The hysteresis area decreases continually with the increase of frequency when E0 < Ec, while <A> first increases then decreases for high E0 situation (E0≥2Ec). Related electrical field and frequency dependent polarization reversal mechanisms are proposed based on the experimental observations.

    更新日期:2018-10-14
  • Synthesis of Co3O4/nitrogen-doped carbon composite from metal-organic framework as anode for Li-ion battery
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Jianghua Qiu, Min Yu, Zehui Zhang, Xing Cai, Guanghui Guo

    In order to overcome the disadvantages of low electrical conductivity and pulverization of Co3O4 anode material, a novel Co3O4/nitrogen-doped carbon composite (Co3O4/N-C) was prepared by annealing a cobalt-based metal-organic framework (MOF) precursor. In this Co3O4/N-C composite, the Co3O4 particles are dispersed uniformly in the matrix of the nitrogen-doped carbon with an average diameter of approximately 10 nm and a mass content of 22.6%. This approach has the advantages that first, the dispersed Co3O4 nanoparticles could increase the lithium ions storage capacity and alleviate the electrode pulverization during the lithium ions insertion/extraction processes; second, the nitrogen-doped carbon material could increase the electrical conductivity of the electrode material and meanwhile serve as a buffer to relieve the structure collapse induced by the large volume change. The as-prepared Co3O4/N-C composite maintains a high reversible discharge capacity of 423 mAhg−1 after 100 cycles at the current density of 100 mAg−1, which is 129% times higher than that of the contrastive nitrogen-doped carbon material. Moreover, this strategy was verified to be effective to produce other transition metal oxides/carbon composite for improving the performance of LIBs.

    更新日期:2018-10-14
  • Study of the structural, magnetic, and microwave absorption properties of the simultaneous substitution of several cations in the barium hexaferrite structure
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Hossein Nikmanesh, Sedigheh Hoghoghifard, Behnaz Hadi-Sichani

    In this research study, multi dopant barium hexaferrites nanoparticles with nominal composition of BaCoxCuxZr2xFe12-4xO19 (x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) have been prepared by sol-gel auto-combustion method. Then, their magnetic and microwave properties were studied in detail. These characteristics were investigated using various instruments including X-ray diffraction (XRD) by the FULLPROF program, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA). The XRD, along with FTIR evaluations confirmed the successful substitution of Co, Cu and Zr cations in the barium hexaferrite lattice. The VSM analysis proved that by increasing cobalt, copper and zirconium substitutions, the saturation magnetization, coercivity and remanence values are decreased. With an increase in the concentration of Co-Cu-Zr ions, a monotonic decrease in coercivity, ranging from 3540 Oe to 396 Oe was also observed. The reasons of the changes in the magnetic and microwave absorption properties by adding the multi dopant were also investigated. The maximum reflection loss of −27.4 dB observed in BaCo0.5Cu0.5ZrFe10O19 sample with a bandwidth of about 5.3 GHz which covered almost whole measured microwave frequency range of 12–18 GHz. Which make it to be a good candidate to design single layer microwave absorber for applying in the Ku band.

    更新日期:2018-10-14
  • Constructing chinky zinc oxide hierarchical hexahedrons for highly sensitive formaldehyde gas detection
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Shuangming Wang, Jing Cao, Wen Cui, Longlong Fan, Xifei Li, Dejun Li
    更新日期:2018-10-14
  • Nb-Pd-Ti BCC thin films for hydrogen separation
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Fatih Pişkin, Tayfur Öztürk

    An investigation was carried out into Nb-Pd-Ti ternary system to determine possible body-centered cubic (b.c.c.) membranes that can be used for hydrogen separation. A library of thin films was produced covering the greater portion of Nb-Pd-Ti ternary diagram using a combinatorial approach. The library was screened both structurally and in terms of a reactivity index defined as the ratio of the resistivity measured in the films under hydrogen and argon. The study showed that a substantial portion of compositional field stretching from Nb to Ti yield thin films with b.c.c. structure. The evaluation based on the reactivity index showed a narrow region close to Nb corner as possible compositions for separation membranes. The b.c.c. field was also screened with regard to the lattice volume so as to identify regions of acceptable hydrogen solubility. The superposition of two maps; one reactivity index and the other lattice volume yield a field 32 < Nb < 41, 27 < Pd < 44, 20 < Ti < 38 as possible compositions for separation membranes.

    更新日期:2018-10-14
  • Impact of MgO–CaO substitution on nucleation behaviors of silicate glasses
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Wenzhe Tang, Shujiang Liu, Shuanglong Lan, Changjiu Li

    The nucleation mechanisms is of particularly technological interest since it determines the subsequent crystal growth and the resultant performances of glass-ceramics. Here we investigate the temperature dependent nucleation behavior of two compositionally similar silicate glasses. Striking difference in nucleation behavior was found for two glasses containing CaO and MgO, respectively, when they underwent the same heat-treatments under isothermal and non-isothermal conditions. Different from the CaO bearing glass for which only surface nucleation occurs, the substitution of MgO for CaO leads to volume nucleation. The comparison of rheological properties shows that the kinetic term with regard to diffusion makes a weak contribution to this difference in nucleation behavior. In contrast, the topological structure plays a key role in nucleation mechanism, which is strongly affected by the degree of intermediate-range order in both the glasses.

    更新日期:2018-10-14
  • Ce3+ and Dy3+ doped Ca3(P1-xBxO4)2 phosphors for white light-emitting applications
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-13
    Meng Lu, Chaofeng Zhu, Zhongtao Chen, Meiling Shi, Xiangeng Meng

    A series of Ce3+, Dy3+ doped Ca3(P1-xBxO4)2 phosphors were synthesized by a high temperature solid-state reaction method, and their corresponding structure, morphology, and luminescence properties were investigated. It is found that the crystal phase transition from β-Ca3(PO4)2 to Ca5(PO4)3(OH) gradually occurs with increasing the boron content in the phosphors, which can provide various local environments for the doping ions and consequently affect the luminescence properties of the phosphors. A red shift of the emission peak of Ce3+ was revealed upon incorporation of boron into Ce/Dy co-doped phosphors. In addition, the luminescence properties could be well modulated by varying the excitation wavelength. The developed phosphors have great potential as a kind of single component white light emitting phosphors for white light emitting diodes.

    更新日期:2018-10-14
  • Synthesis and optical properties of Ba3Bi2 (PO4)4:Dy3+ phosphors for white light emitting diodes
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-13
    M. Jayachandiran, S. Masilla Moses Kennedy

    The single-component Dy3+ activated Ba3Bi2(PO4)4 white light emitting phosphors were prepared by solid state reaction method. The phase formation of these phosphors was characterized by powder X-ray diffraction (PXRD) patterns. The photoluminescence properties and the surface morphology of these phosphors were investigated. The excitation spectrum of the Dy3+ characteristic emission at 575 nm exhibited narrow bands in the 300–450 nm range. Exciting the Ba3Bi2-x(PO4)4:xDy3+ x = 0.03, 0.06, 0.09, 0.12, 0.15, 0.18(here after abbreviated as BaBiPO:Dy3+) phosphor with 349 nm (near UV), the emission bands were observed at 470 nm (blue), 575 nm (yellow) and 664 nm (red) corresponding to the transitions (4F9/2 → 6H15/2), (4F9/2 → 6H13/2), and (4F9/2 → 6H11/2) respectively. The phosphor with x = 0.09 Dy3+ ion showed the maximum luminescence intensity. The luminescence lifetime of these phosphors were found to be in the millisecond range. The temperature dependent luminescence of BaBiPO:0.09Dy3+ phosphor for 349 nm excitation was investigated and the calculated activation energy, ΔE, was 0.262 eV. The quantum efficiency and the colour rendering index were calculated. In addition, the Commission International del'Eclairagethe (CIE) chromaticity coordinates of these phosphors were found to be located in the near white region (x = 0.329, y = 0.349). These results indicate that the BaBiPO:Dy3+ phosphor has great potential as a single-component white-light-emitting phosphor for near-UV excitation.

    更新日期:2018-10-14
  • Rational design of red phosphorus/reduced graphene oxide composites for stable sodium ion storage
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-13
    Na Feng, Xiaoqiang Liang, Xiong Pu, Meng Li, Mengmeng Liu, Zifeng Cong, Jiangman Sun, Weixing Song, Weiguo Hu
    更新日期:2018-10-14
  • Facile synthesis of Zinc Vanadate Zn3(VO4)2 for highly efficient visible light assisted photocatalytic activity
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-13
    Muhammad Munir Sajid, Naveed Akthar Shad, Sadaf Bashir Khan, Zhengjun Zhang, Nasir Amin
    更新日期:2018-10-14
  • Effects of temperature and microstructure on the triblogical properties of CoCrFeNiNbx eutectic high entropy alloys
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-13
    Yuan Yu, Feng He, Zhuhui Qiao, Zhijun Wang, Weimin Liu, Jun Yang

    This paper is aimed to evaluate the high temperature tribological behaviors of CoCrFeNiNbx eutectic high entropy alloys which would be highly-promising candidates for high-temperature applications. The effects of testing temperature and material structure on the friction and wear properties are investigated. The CoCrFeNiNbx alloys display a low harness decrement rate about 35% from room temperature to 1000 °C, indicating good softening resistance. The main wear mechanisms are abrasion wear at room temperature, change to adhesion wear at 400 °C, and translate into oxidation wear and mechanical wear over 600 °C. The wear rates increase from room temperature to 400 °C and decrease afterwards. The effects of material structure are dominated by the hardness of alloy, the content of chemically active Nb element and the structure of oxidized tribo-layer. The compact oxidized tribo-layers with excellent anti-wear properties are formed on the worn surface of CoCrFeNiNb0.65 and CoCrFeNiNb0.8 alloys at 800 °C, leading to extremely low wear rate.

    更新日期:2018-10-14
  • Effect of additional solute elements (X= Al, Ca, Y, Ba, Sn, Gd and Zn) on crystallographic anisotropy during the dendritic growth of magnesium alloys
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-13
    Jinglian Du, Ang Zhang, Zhipeng Guo, Manhong Yang, Mei Li, Feng Liu, Shoumei Xiong

    Based on the first-principles calculations and crystallographic anisotropy analysis, the effect of additional solute elements on the dendritic growth behavior of binary Mg-X (X = Al, Ca, Y, Ba, Sn, Gd and Zn) alloys are investigated in terms of the orientation-dependent surface energy. The preferred growth direction of the α-Mg dendrite is found to be dependent on the magnitude of the anisotropic surface energy and the difference of crystallographic anisotropy between the matrix Mg and the additional solute X. The most densely packed crystallographic planes are found to be the energetically favorable planes with the minimum surface energy, as exemplified by the {111} plane of Al with fcc (face-centered cubic) structure, the {110} plane of Ba with bcc (body-centered cubic) structure, and the {0001} plane of Y with hcp (hexagonal-close packed) structure. For all additional solute elements studied, Zn exhibits the maximum anisotropy and the according effect on the growth behavior of the α-Mg dendrite is the most significant, which could also be reflected by the complex growth patterns of the Mg-Zn alloy dendrite observed in experiments. Compared with Zn, the crystallographic anisotropy of the other additional solutes is weaker, and their effect on the α-Mg dendrite growth is not as significant as Zn, which is reflected by their similar eighteen-primary branch dendritic morphology in 3D.

    更新日期:2018-10-14
  • Nucleation and growth of graphite particles in ductile cast iron
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-13
    André de Albuquerque Vicente, João Roberto Sartori Moreno, Tiago Felipe de Abreu Santos, Denise Crocce Romano Espinosa, Jorge Alberto Soares Tenório
    更新日期:2018-10-14
  • Ab initio study of the role of defects on the magnetic response and the structural, electronic and hyperfine properties of ZnFe2O4
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-13
    J.J. Melo Quintero, K.L. Salcedo Rodríguez, C.E. Rodríguez Torres, L.A. Errico

    In this work the effects of defects (oxygen vacancies, cationic inversion) on the structural, electronic and the magnetic response of the spinel ZnFe2O4 (ZFO) are studied by using a density functional theory (DFT) based ab initio method (the Full-Potential Linearized Augmented Plane Waves plus Local Orbitals, LAPW+lo) on the framework of the Generalized Gradient Approximation plus U (GGA+U) level. The changes induced by the defects in the hyperfine interactions at the Fe sites of the structure are also presented. In order to discuss the magnetic ordering and the electronic structure of the system we considered different spin arrangements. We found that, similar to the normal and pristine case, reduced and partially inverted ZFO presents an energy landscape characterized by a large number of metastable states. Our calculations successfully describe the hyperfine properties (isomer shift, magnetic hyperfine field and quadrupole spliting) at the Fe sites that are seen by Mössbauer Spectrocopy (MS) at 4 and 300 K, enabling us to characterize the local structure around Fe atoms. Our LAPW+lo predictions also demonstrate the relevance of both oxygen vacancies and antisites (cationic inversion) in the formation of local ferromagnetic coupling between Fe ions, giving rise to a ferrimagnetic ordering in an otherwise antiferromagnetic compound. This results support conclusions based in experimental results obtained in x-ray magnetic circular dichroism and magnetization measurements performed on zinc ferrites with different cation distributions and oxygen vacancy concentrations reported in the literature.

    更新日期:2018-10-14
  • Sol-gel derived aluminium doped zinc oxide thin films: A view of aluminium doping effect on physicochemical and NO2 sensing properties
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-13
    A.R. Nimbalkar, N.B. Patil, V.V. Ganbavle, S.V. Mohite, K.V. Madhale, M.G. Patil
    更新日期:2018-10-14
  • Structural, morphological, Raman and ac electrical properties of the multiferroic sol-gel made Bi0.8Er0.1Ba0.1Fe0.96Cr0.02Co0.02O3 material
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-13
    A. Benali, B.M.G. Melo, P.R. Prezas, M. Bejar, E. Dhahri, M.A. Valente, M.P.F. Graça, B.A. Nogueira, B.F.O. Costa

    We have investigated the effect of multi-doping in A and B site of the multiferroic prepared by the Sol-gel method Bi0.8Er0.1Ba0.1Fe0.96Co0.02Cr0.02O3 (BEBFCC) on the structural, morphological and electric properties. X-Ray diffraction and Rietveld refinement confirm that the BEBFCC compound presents a rhombohedral structure with the R3C space group. The Ac electrical properties have been measured from 331 to 735 K as a function of frequency (100 kHz - 1 MHz). Debye's theory and Arrhenius relations were used to study the relaxation phenomenon. The frequency dependence of the impedance (Z”: imaginary part) reveals the existence of one relaxation peak, while the Modulus formalism shows two peaks. The presence of two contributions, related to the dielectric relaxations visible in this compound, was confirmed by the Impedance Nyquist plots. The study of the ac conductivity based on Jonsher's power law confirms that the conduction is associated to the Non-Overlapping Small Polaron Tunneling model.

    更新日期:2018-10-14
  • 更新日期:2018-10-14
  • 更新日期:2018-10-14
  • Rapid floating zone growth of Ni2MnGa single crystals exhibiting magnetic shape memory functionality
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-14
    Petr Cejpek, Ladislav Straka, Martin Veis, Ross Colman, Milan Dopita, Václav Holý, Oleg Heczko

    To obtain a material exhibiting magnetically induced reorientation (MIR), one of the magnetic shape memory effects, a well-developed method for single crystal growth is crucial. A [100] oriented Ni2MnGa single crystal exhibiting MIR was successfully prepared using the floating-zone technique with a high speed of 80 mm/h. The comparison with a sample grown by Bridgman method and a reference sample grown in AdaptaMat Ltd. by directional solidification is provided based on elemental homogeneity, crystallographic quality by x-ray diffraction, transformation behaviour and magnetic properties. All these methods indicated that the single crystal grown by floating zone with high speed is comparable or superior to the samples prepared by other methods. Importantly, the magnetization measurement revealed that the single crystal prepared this way exhibits MIR down to 10 K.

    更新日期:2018-10-14
  • Thermodynamic properties of MgGa2O4 and phase relations in the system Mg-Ga-O
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-14
    K.T. Jacob, Shivesh Sivakumar
    更新日期:2018-10-14
  • A cobalt and nickel co-modified layered P2-Na2/3Mn1/2Fe1/2O2 with excellent cycle stability for high-energy density sodium-ion batteries
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-14
    Shiyong Chu, Yubo Chen, Jie Wang, Jie Dai, Kaiming Liao, Wei Zhou, Zongping Shao
    更新日期:2018-10-14
  • Understanding the magnetic structural transition in all-d-metal Heusler alloy Mn2Ni1.25Co0.25Ti0.5
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    Zhaoning Ni, Xingmiao Guo, Xiaotong Liu, Yiyang Jiao, Fanbin Meng, Hongzhi Luo

    Mn-Ni-Co-Ti alloys are newly reported all-d-metal Heusler alloys with magnetic field induced martensitic transformation and large volume discontinuity. Here we investigated the electronic structure and magnetic structural transition in Mn2Ni1.5Ti0.5 and Mn2Ni1.25Co0.25Ti0.5 theoretically. In these alloys, the same number of Mn atoms enter D (0.75, 0.75, 0.75) site when extra Ni/Co substitute for Ti. Mn (D) spin moment is parallel to that of Mn at B (0.25, 0.25, 0.25) site in cubic austenitic phase but becomes antiparallel in tetragonal martensitic phase. Then during the martensitic transition, the total magnetic moment decreases obviously. Compared with Mn2Ni1.5Ti0.5, the doping of Co in Mn2Ni1.25Co0.25Ti0.5 can enlarge the energy difference between the antiparallel and parallel configurations of Mn (B) and Mn (D) moments and thus stabilize the ferromagnetic coupling between them in austenite. DOS structure and charge density difference reveal this is related to the strong d-d hybridization between Co-Mn nearest neighbors. That is the origin of the “FM activation effect” of Co-doping in literature. The “volume-conserving assumption” may need improvement in all-d-metal Heusler alloys. The lowest total energy for Mn2Ni1.25Co0.25Ti0.5 martensitic was obtained when its cell volume is smaller than the equilibrium cell volume of the austenite. The predicted volume contraction is as large as 3.5% with a c/a ratio of 1.45. These results give reasonable explanations for existing experimental observations.

    更新日期:2018-10-12
  • Trace carbon-hybridized ZnS/ZnO hollow nanospheres with multi-enhanced visible-light photocatalytic performance
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    Zhimei Zou, Xiaoyan Yang, Peng Zhang, Yiming Zhang, Xiaoxiao Yan, Rongmei Zhou, Dan Liu, Lin Xu, Jianzhou Gui
    更新日期:2018-10-12
  • Enhanced visible-light-driven photocatalytic H2 evolution on the novel nitrogen-doped carbon dots/CuBi2O4 microrods composite
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    Weilong Shi, Feng Guo, Mingyang Li, Yu Shi, Mingfang Wu, Yubin Tang

    A novel nitrogen doped carbon dots (N-CDs) modified CuBi2O4 photocatalyst was prepared through a facile hydrothermal method, and applied to the photocatalytic water splitting under visible light irradiation (λ > 400 nm). Results exhibited the increased photocatalytic hydrogen production of N-CDs/CuBi2O4 compared with pure CuBi2O4 and CDs/CuBi2O4. The excellent photocatalytic performance of N-CDs/CuBi2O4 composite was attributed to efficient synergistic effect between N-CDs and CuBi2O4, which increased light harvesting and electron transfer capacity. Additionally, a possible photocatalytic mechanism of N-CDs/CuBi2O4 composite was proposed.

    更新日期:2018-10-12
  • Ultrafine Ni2P nanoparticles embedded in one-dimensional carbon skeleton derived from metal-organic frameworks template as a high-performance anode for lithium ion battery
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    R.Z. Zhang, K.J. Zhu, J.D. Huang, L.Y. Yang, S.T. Li, Z.Y. Wang, J.R. Xie, H. Wang, J. Liu

    The exploration of high-performance anode materials by designing different synthesis methods is crucial to the development of next generation lithium ion batteries (LIBs). Ultrafine Ni2P nanoparticles embedded in one-dimensional carbon skeleton derived from metal-organic frameworks template are obtained and used as LIBs anode electrode. The unique architecture of Ni2P@C electrode delivered a high capacity of 610.4 mA h g−1 at the current density of 100 mA g−1, excellent rate capability and superior cycling stability with no obvious capacity decay over 400 cycles at a high current of 500 mA g−1, indicating the promising potential for LIBs application. Significantly, this design method of nanoparticles embedded in carbon skeleton may become a novel strategy for synthesizing other metal phosphides used as next generation LIBs anode materials.

    更新日期:2018-10-12
  • Elasto-plastic deformation in Al-Cu cast alloys for engine components
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    M. Schöbel, R. Fernández, R. Koos, J. Bernardi
    更新日期:2018-10-12
  • Luminescence property, energy transfer and thermal property of color tunable phosphor Ca9-wCe0.5Y0.5-x-y-z(PO4)7:xTb3+, yEu3+, zSm3+, wMn2+
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Rongzhi Gu, Mengyuan Guan, Na Jiang, Tianyu Yuan, Guoquan Ma, Chao Wang, Zhiping Yang, Panlai Li, Zhijun Wang

    Series of Ca9-wCe0.5Y0.5-x-y-z(PO4)7:xTb3+, yEu3+, zSm3+, wMn2+ phosphors are synthesized by a high temperature solid state method. The spectral property and fluorescence decay curves are measured and used to demonstrate the energy transfer effect in Ce3+-Tb3+, Ce3+-Sm3+, Ce3+-Eu3+, Tb3+-Sm3+, Tb3+-Eu3+ and Tb3+-Mn2+. For Ca9Ce0.5Y0.5(PO4)7, the concentration of Ce3+ is higher and it can act as activator and sensitizer simultaneously. Ce3+ and Tb3+ can emit blue and green light under near ultraviolet excitation, respectively. Sm3+, Eu3+ and Mn2+ can produce red emission. In order to generate white light, Ce3+/Tb3+/Sm3+, Ce3+/Tb3+/Eu3+ and Ce3+/Tb3+/Mn2+ doped phosphors are investigated, and Ca8.8Ce0.5Y0.33(PO4)7:0.17Tb3+,0.20Mn2+ can create high quality white light. Its color rendering index can be high up to 80.2 and correlated color temperature is 4735 K, and its thermal stability is high. The result indicates that the acquired phosphors can be potential for the use of ultraviolet excited white light emitting diodes.

    更新日期:2018-10-12
  • Effects of calcination temperature on the electromagnetic properties of carbon nanotubes/indium tin oxide composites
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Chaoqun Ge, Liuying Wang, Gu Liu, Renbing Wu

    Carbon nanotubes (CNTs)/Indium tin oxide (ITO) composites have been successfully synthesized via coprecipitation and calcination processes. The effects of calcination temperature on the electromagnetic properties of the CNTs/ITO composites were investigated. The real part of the permittivity and the dielectric loss increase with increasing calcination temperature, which can be attributed to the enhanced dielectric relaxation and space charge polarization. The CNTs/ITO composites synthesized at 600 °C can achieve lower reflection loss (RL) value at the thickness of 2–4 mm, while the composites synthesized at 850 °C exhibit broader bandwidth, corresponding to an RL value below −10 dB at a thin coating thickness of 1–1.5 mm. The microwave absorption properties of the CNTs/ITO composites at different frequencies can be tuned by controlling the calcination temperature and the thickness of the absorbing coating. The dielectric loss, quarter-wavelength cancellation, and well-matched characteristic impedance in the air-absorber interface are believed to contribute to the superior microwave absorption performance of the composites. The effects of the secondary phase ITO on the electromagnetic properties of the CNTs/ITO composites were also discussed in this study.

    更新日期:2018-10-12
  • The formation of disordered intermetallic phase during the solid-state interaction of WC with Ir
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    V. Rybin, V. Lozanov, A. Utkin, A. Matvienko, N. Baklanova
    更新日期:2018-10-12
  • (NH4)3AlF6:Mn4+ a novel red phosphor – Facile synthesis, structure and luminescence characteristics
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-12
    Usama Bin Humayoun, Seok Bin Kwon, Syed Kamran Sami, Dae-Ho Yoon

    Among various red phosphors, Mn4+ activated fluoride hosts have received much attention due to their blue excitability and intense red emission. In this study we report a novel (NH4)3AlF6:Mn4+ phosphor, synthesized through a facile synthesis process avoiding high quantities of highly toxic HF acid. The synthesized host exhibit cubic structure in F-4 3m space group, with plenty of [AlF6]3+ octahedral sites. When activated with Mn4+ the crystal structure is retained and the material exhibits characteristic excitation bands with maximum around 469 nm and intense red emission around 631 nm. Furthermore, the thermal gravimetric analysis revealed the stability of composition up to 250 °C. The phosphor however exhibits high sensitivity to increased temperature and showed sharp quenching of luminescence at elevated temperatures.

    更新日期:2018-10-12
  • In-situ dispersed La oxides of Al6061 composites by mechanical alloying
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-10
    Chun-Liang Chen, Chen-Han Lin

    Aluminum-based metal matrix composites (MMCs) are useful materials for structural applications due to their high strength to weight ratio. In this study, the addition of the rare earth element La to the Al6061 alloys as in-situ La oxide dispersoids fabricated by mechanical alloying was investigated. The result shows that an increase of La content can change the morphology of synthesized powders and has significant influence on microstructure uniformity, hardness, densification, and ductility of the materials. The results also show that the complex La-Al-Si-O oxides and needle-like AlFeSi intermetallic compounds were formed during ball milling and subsequent sintering processes.

    更新日期:2018-10-11
  • Controlled synthesis of nickel-rich layered oxide cathodes with preferentially exposed {010} active facets for high rate and long cycling stable lithium-ion batteries
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-10
    Wei Xiang, Wen-Yuan Liu, Jun Zhang, Shuo Wang, Ting-Ting Zhang, Kai Yin, Xi Peng, Yong-Chao Jiang, Kai-Hong Liu, Xiao-Dong Guo

    Controlling hierarchical structure assembled by nanoplates with exposed {010} active planes is essential to optimize the electrochemical performance of nickel-rich layered oxide cathode materials. In this work, nickel-rich layered oxide cathodes with various degrees of packing and surface area of exposed {010} facets were synthesized via a simple continuous co-precipitation method and a stepwise calcination process. The effects of structure and morphology on the Li+ transport kinetics of LiNi0.58Co0.25Mn0.17O2 were systematically evaluated by physical and electrochemical characterizations. The results show that the enhanced growth of {010} active facets, namely, the lateral plane of the primary nanoplates can facilitate the Li+ intercalation/deintercalation and thus improve the rate capability. Meanwhile, the compact micro-sized secondary particle guarantees the structural stability of the Ni-rich cathodes. The LiNi0.58Co0.25Mn0.17O2 material with optimized structure manifests high discharge capacities (185 mAh g−1 at 0.1 C), outstanding high-rate capability (106 mAh g−1 at 50 C) and excellent long cycle life (capacity retention of 78% after 500 cycles at 5 C).

    更新日期:2018-10-11
  • Formation, photoluminescence and ferromagnetic characterization of Ce doped AlN hierarchical nanostructures
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-10
    Qiushi Wang, Wanze Wu, Jian Zhang, Ge Zhu, Ridong Cong

    Cerium doped aluminum nitride (AlN:Ce) hierarchical nanostructures were fabricated by a direct reaction of Al and CeO2 mixed ingot with ammonia using modified arc discharge method. X-ray diffractometry, Raman spectrum and x-ray photoelectron spectroscopy analysis obviously indicated that Ce3+ ions incorporated inside the AlN nanostructures. The prepared AlN:Ce exhibited a strong red-orange emission at 600 nm and showed room temperature ferromagnetism. These results suggest that AlN:Ce hierarchical nanostructures have potential as a light-emission nanodevice and diluted magnetic semiconductor.

    更新日期:2018-10-11
  • Influence of solution heat treatment on the microstructural evolution and mechanical behavior of 60NiTi
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-10
    G.X. Xu, L.J. Zheng, F.X. Zhang, H. Zhang

    The microstructures and mechanical properties of 60NiTi alloys after solution treated at 980 °C, 1005 °C, 1030 °C and 1055 °C for 2 h, 4 h, 8 h were studied. The results showed that there was undissolved Ni3Ti phase in the specimens after heat treated at 980 °C and 1005 °C for 8 h, and the specimens consisted of Ni3Ti, B2 NiTi and Ni4Ti3 phase. The volume fraction of the Ni4Ti3 phase was about 36% and 46% respectively. After heated at 1030 °C and 1055 °C for 8 h, specimens consisted of B2 NiTi and Ni4Ti3 phase, and the Ni3Ti phase was totally dissolved into the matrix. As a result, the volume fraction of Ni4Ti3 phase increased to 69% and 64%. Higher density of the Ni4Ti3 phase contributed to the higher hardness and higher ultimate compressive strength. The fracture modes of samples after solution treated were mainly quasi-cleavage fracture. The undissolved Ni3Ti phase improved the fracture toughness of the binary alloy. Crack propagation path in Ni3Ti rich area was featured by a zigzag mode, which indicated that Ni3Ti phase displayed positive effect on fracture toughness. The toughening mechanism of 60NiTi with Ni3Ti phase is emphasized.

    更新日期:2018-10-11
  • Adjustment of the microstructure and selected mechanical properties of biomedical Ti-15Zr-Mo alloys through oxygen doping
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-10
    D.R.N. Correa, P.A.B. Kuroda, M.L. Lourenço, M.A.R. Buzalaf, C.R. Grandini

    This study investigated the effect of oxygen doping on the crystalline structure, microstructure, and selected mechanical properties (Vickers microhardness, Young's modulus and internal friction) of Ti-15Zr-xMo (x = 5, 7.5, 10, 15 and 20 wt%) alloys for use as biomaterials. The monitoring of oxygen pressure along with the doping treatment indicated that the interstitial element was successfully absorbed into the samples. Results showed that oxygen content slightly altered the α”/β phase proportion and β phase crystalline parameter without abruptly changing their microstructure. Moreover, the selected mechanical properties suffered variations in a non-linear manner. Oxygen content was found to be suitable to produce small variations in the microstructure and in the selected properties of biomedical Ti alloys, keeping the main composition unchanged.

    更新日期:2018-10-11
  • 更新日期:2018-10-11
  • Recent development of mixed transition metal oxide and graphene/mixed transition metal oxide based hybrid nanostructures for advanced supercapacitors
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-10
    Wei Hau Low, Poi Sim Khiew, Siew Shee Lim, Chiu Wee Siong, Ejikeme Raphael Ezeigwe
    更新日期:2018-10-11
  • 更新日期:2018-10-11
  • Functional properties of percolative CoFe2O4 - PbTiO3 composite ceramics
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-10
    Cristina E. Ciomaga, Mirela Airimioaei, Ina Turcan, Alexandru V. Lukacs, Sorin Tascu, Marian Grigoras, Nicoleta Lupu, Juras Banys, Liliana Mitoseriu

    The structural, microstructural, electrical and magnetic characteristics of CoFe2O4-PbTiO3 composite ceramics with various amounts of magnetic phase are reported. The magnetization as a function of magnetic field and temperature showed a “dilution effect” when decreasing the ferrite amount, while the magnetic Curie temperature remains in the range of about 750 K for all the compositions, with small shifts due to the possible doping. The maximum value of magnetostriction response of 122 ppm, was obtained for the composition with 85% amount of ferrite at a field of 8 kG. The variation of dielectric properties with frequency and temperature in the range of (300–800)K is characterised by a frequency independent peak derived from the ferroelectric-to-paraelectric phase transition of PbTiO3 component and two frequency dependent thermally activated relaxations: one in the range of (300÷420)K with an activation energy of 0.5–0.6eV and one in the paraelectric state at (420÷650)K, with an activation energy of ∼1.2÷1.4eV which were described in terms of charge defects in the composite system.

    更新日期:2018-10-11
  • Partitioning of C into κ-carbides by Si addition and its effect on the initial deformation mechanism of Fe-Mn-Al-C lightweight steels
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-10
    C.W. Kim, M. Terner, J.H. Lee, H.U. Hong, J. Moon, S.J. Park, J.H. Jang, C.H. Lee, B.H. Lee, Y.J. Lee
    更新日期:2018-10-11
  • High-performance lithium-ion battery anodes based on Mn3O4/nitrogen-doped porous carbon hybrid structures
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    Liewu Li, Liping Wang, Mingyu Zhang, Qizhong Huang, Libao Chen, Feixiang Wu

    Manganese oxide is a promising anode material in next-generation rechargeable batteries due to its high theoretical specific capacity and low reduction potential. Here we report a facile and scalable approach to fabricate the novel Mn3O4 and nitrogen-doped porous carbon hybrid nanocomposite (Mn3O4/C-N) as lithium-ion battery anodes. The obtained nanocomposite has numerous nanosized Mn3O4 nanoparticles (∼30 nm), which are uniformly dispersed in N-doped porous carbon matrix (the N content is ∼12.2%). The N-doped porous carbon matrix can not only improve the electronic conductivity and increase the Li+ storage active sites, but also accommodate the structural stress generated by volume change of Mn3O4 nanoparticles during cycling. Remarkably, the Mn3O4/C-N anode exhibits long-term cycling stability for a reversible discharge capacity of 945 mA h g−1 (the specific capacity is calculated using the mass of the whole hybrid) at a current density of 1 A g−1 after 400 cycles, indicating a capacity retention of 94.7%. The Mn3O4/C-N anode with excellent performance shows its immense potential for lithium-ion batteries.

    更新日期:2018-10-11
  • Studies on Shubnikov-de Haas oscillations and magnetic properties of cobalt-doped Bi1.9Co0.05 Sb0.05Se3 topological single crystals
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    E.P. Amaladass, A.T. Satya, Shilpam Sharma, K. Vinod, Awadhesh Mani
    更新日期:2018-10-11
  • Effect of Ho doping on the crystal structure, surface morphology and magnetic property of BiFeO3 thin films prepared via the sol-gel technology
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    Pugeng Hou, Bao Liu, Zhendong Guo, Pengyu Zhou, Bo Wang, Lei Zhao

    Multiferroic material bismuth ferrite (BiFeO3 = BFO) and Ho-substitution (Bi1-xHoxFeO3, x = 0.05, 0.10, 0.15, 0.20) thin films were successfully fabricated on silicon (110) substrates by the sol-gel approach. The doping-Ho effects on crystal structure, surface morphology and magnetic property were investigated. The X-ray diffraction (XRD) revealed that the Ho-substitution thin films underwent a phase transition from the rhombohedral to the orthorhombic structure. The changes in Ho-substitution and pure BFO surface appearance were analyzed using the Field Emission Scanning Electron Microscopy (SEM). Meanwhile, the saturation magnetization (Ms) of Ho-substitution samples obtained remarkable augment with the increase in Ho-doping due to the enhancement of superexchange interactions between Fe-O-Fe and spatial modulation for helical structure destruction. The heightening of superexchange interactions is attributed to the reduction of oxygen vacancies because of Ho3+ ions in a stable status.

    更新日期:2018-10-11
  • Structure and optical properties of La2-xGdxSiO5:Dy3+ phosphors
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    Simon N. Ogugua, Samy K.K. Shaat, Hendrik C. Swart, Robin E. Kroon, Odireleng M. Ntwaeaborwa
    更新日期:2018-10-11
  • Heat treatment effect on the microstructure and corrosion behavior of Al-6061 alloy with influence of α-nanoalumina reinforcement in 3.5% NaCl solution
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    Vikas Shrivastava, Gaurav Kumar Gupta, I.B. Singh

    Al-6061 alloy based nanocomposites were synthesized using sol-gel prepared nanoparticles of α-alumina in their varying weight percentages (0, 0.5, 1.5, and 2.5 wt%) via powder metallurgy route. The synthesized nanocomposites were sintered and heat treated under solutionized and T6 conditions. Afterwards, electrochemical corrosion tests were performed in 3.5% NaCl solution to see the effect of nanoparticle addition on the corrosion behavior of the composites. Heat treatment results indicate that solutionized composites exhibit better corrosion resistance as compared to the composites treated under sintered condition. Heat treatment under T6 condition showed poorest corrosion resistance. Nanocomposite reinforced with 0.5 wt% of nanoparticles showed excellent corrosion resistance than that of 1.5 wt% of nanoalumina incorporated composite. After 2.5 wt% incorporation of nanoparticles, the corrosion rate of the composite becomes very high even more than that of the base alloy. Increase of nanoparticle concentration was found to increase their agglomeration at the grain boundary region that increases porosity in the composite. This ultimately increases the corrosion reaction because of the enhanced chemical reactivity. The microstructural examination of the synthesized nanocomposites were found in good agreement with the corrosion rate determined from electrochemical tests.

    更新日期:2018-10-11
  • Lattice distortion in TmCo2: A poly- and single-crystal study
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    J. Šebesta, D. Kriegner, J. Prchal

    Within the RCo2 family of compounds, a structural distortion linked with the onset of magnetic ordering around the critical temperature can be observed. One of the less explored RCo2 compounds is TmCo2 probably due to its low Curie temperature. Exceptionally this compound, given its position at the end of the ferrimagnetic series, shows discrepancies in the ordering of the Co sub-lattice because of a weak Weiss molecular field. In this paper we focus on the structural distortion in TmCo2, which appears together with the magnetic ordering around the critical temperature of TC∼3.6 K. Poly-crystals as well as single-crystals of TmCo2 were used in our experiments. For both kinds of samples we observed the same type of the rhombohedral distortion along the [111] direction from the cubic Fd3¯m to R3¯m space group. The relation between observed magnetic and structural properties in this compound is discussed.

    更新日期:2018-10-11
  • Hydrogen sorption in TiZrNbHfTa high entropy alloy
    J. Alloys Compd. (IF 3.779) Pub Date : 2018-10-11
    C. Zlotea, M.A. Sow, G. Ek, J.-P. Couzinié, L. Perrière, I. Guillot, J. Bourgon, K.T. Møller, T.R. Jensen, E. Akiba, M. Sahlberg
    更新日期:2018-10-11
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.
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