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Key engineering materials
Trans Tech Publications Ltd.
Key engineering materials

Trans Tech Publications Ltd.

半月刊

1013-9826

Key engineering materials/Journal Key engineering materials
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    Fabrication and Properties of PZT-cement-encapsulated carbon Composites

    Arnon ChaipanichNittaya Jaitanong
    428-431页
    查看更多>>摘要：Lead zirconate titanate, Pb(Zr_(0.52)Ti_(0.48))O_3 (PZT) has excellent piezoelectric properties and has been used in a number of applications such as sensors and actuators. Recently, PZT has been used with a cement based material to produce new types of composite. These new piezoelectric-cement based composites have been developed for sensor applications in civil engineering works where these composites would provide better matching to concrete than the existing normal piezoelectric ceramic or piezoelectric-polymer composites. In this work, encapsulated carbon addition of 2% by volume was added to the PZT-cement composites using pressed-cured method. Dielectric properties of the composites were investigated from 1 to 100 kHz as a preliminary investigation. The results show that the dielectric constant was found to be higher for the composite with the addition of encapsulated carbon. The dielectric loss of the composite with the encapsulated carbon, however, was found to be less when compared to the composite with no encapsulated carbon. Scanning electron micrographs of these composites also revealed that a dense microstructure can be obtained from this method.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Artificial Neural Network Modeling of Ferroelectric Hysteresis: An Application to Soft Lead Zirconate Titanate Ceramics

    Wimalin LaosiritawornRattikorn YimnirunYongyut Laosiritaworn
    432-435页
    查看更多>>摘要：In this work, the Artificial Neural Network (ANN) was used to model ferroelectric hysteresis using data measured from soft lead zirconate titanate [Pb (Zr_(1-x)Ti_x)O_3 or PZT] ceramics as an application. Data from experiments were split into training, testing and validation dataset. Four ANN models were developed separately to predict output of the hysteresis area, remnant, coercivity and squareness. Each model has two neurons in the input layer, which represent field amplitude and field frequency. The ANNs were trained with varying number of hidden layer and number of neurons in each layer to find the best network architecture with highest accuracy. After the networks have been trained, they were used to predict hysteresis properties of the unseen testing patterns of input. The predicted and the testing data were found to match very well which suggests the ANN success in modeling ferroelectric hysteresis properties obtained from experiments.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Composition, Structure and Properties of PZT-BT Ceramics Prepared by Two-stage Sintering

    Wanwilai C. VittayakornRattikorn YimnirunSupon Ananta
    436-439页
    查看更多>>摘要：Ceramic solid solutions within the system (1-x)PZT-xBT, where x = 0.1, 0.2, 0.3, 0.4 and 0.5, were prepared by conventional mixed-oxide method combined with a two-stage sintering procedure. A sintering time of 2 h at 1000 ℃ followed by a second step in the temperature range of 1000-1200 ℃ for 2 h was employed to all samples and compared to the one-step sintering process. Phase formation, densification and microstructure of all ceramics were examined via X-ray diffraction (XRD), Archimedes method and scanning electron microscope (SEM). The results lead to the conclusion that the pure perovskite phase and high densification of (1-x)PZT-xBT ceramics with fine grain can be successfully achieved under suitable two-stage sintering conditions.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Mixed Conduction of Proton and Electron in Tungsten Phosphate Glass and Its Hydrogen Transport

    Satoru FujitsuHiroshi Kawazoe
    443-446页
    查看更多>>摘要：The transference number of protons and the hydrogen transport behavior through tungsten phosphate glass have been measured through the use of a concentration cell. Based on measurement of the electrical motive force by changing the hydrogen partial pressure of both sides of a specimen glass kept in the concentration cell, the ionic transference number was estimated to be 48%. When one side is kept in hydrogen and the other in nitrogen, hydrogen transport is observed and its quantity is accelerated by applying a positive dc bias on the hydrogen side. After applying the dc bias continuously for over 1 h, the hydrogen transport is abruptly increased with no cracks and the hydrogen flux is 1.5×10~(-3) μmolcm~(-2)s~(-1).
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Nanocomposite SPEEK/Titania Nanosheets (TNS) Proton Exchange Membranes for Fuel Cell Applications

    Debora MaraniSilvia LicocciaEnrico TraversaMasaru Miyayama...
    447-450页
    查看更多>>摘要：SPEEK-based composite membranes containing various amounts of titania nanosheets (TNS) as inorganic fillers were investigated for proton exchange membrane fuel cell applications. The samples were characterized for water uptake, proton conductivity (E1S), and structural features (SEM and XRD). Composites at low inorganic additive contents exhibited improved properties in terms of proton conductivity and water uptake behavior. Best improvements were observed for the composite containing only 0.95 wt% of TNS. This result could be associated to the unique nature of the two dimensional nanostructure of the inorganic additive.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Effect of Sendust Particle Size on Absorption Characteristics of Composite Electromagnetic Wave Absorber

    Kenji SakaiYoichi WadaYuuki SatoShinzo Yoshikado...
    451-454页
    查看更多>>摘要：The effects of the particle size of sendust, which is an alloy of Al 5%, Si 10%, and Fe 85%, on the absorption characteristics of composite electromagnetic wave absorbers made of polystyrene resin and sendust were investigated in the frequency range from 1 to 40 GHz. The size of sendust particles was varied between approximately 5 and 20 μm. A metal-backed single-layer absorber made of 20 urn sendust particles absorbed more than 99% of electromagnetic wave power at frequencies above 20 GHz. Meanwhile, a composite made of 5 μm particles exhibited a return loss of less than -20 dB in the frequency range of not only several GHz but also above 30 GHz. In addition, the relative complex permeability μ_r~* was shown to be controlled by adjusting the particle size of sendust, and an electromagnetic wave absorber with a flexible design was proposed.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Ion Exchange of Layer Structured Crystal CsTiNbO_5 and Its Application as Cathode Material in a Rechargeable Lithium Battery

    Masao Ohashi
    455-458页
    查看更多>>摘要：The layer structured titanoniobate CsTiNbO_5 has been prepared in a solid state reaction using Cs_2CO_3, anatase type TiO_2 and Nb_2O_5 at 1073 K. Ion exchange reactions of Cs~+ in the interlayer space were studied in aqueous solutions. The host layers of the titanoniobate were maintained on the ion exchange reactions and the resulting products were found to contain interlayer water. The interlayer water in the lithium ion exchange product was removed by heating at 453 K in a vacuum. The resulting titanoniobate Cs_(0.10)Li_(0.60)H_(0.30)TiNbO_5 was evaluated for its use as the cathode in a rechargeable lithium battery. The cathode exhibited discharge and charge capacities of 130 and 99 mAhg~(-1) for the first cycle in the voltage range of 1.5 - 4.2 V. The amounts of Li~+ intercalated and deintercalated were 1.16 and 0.88 of the formula unit, respectively.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Electrocatalytic Activities of Trirutiles Based on MTaO_6 (M=Co, Ni, Mg) for Oxygen Reduction Reaction

    Takayuki KONISHIHideki KAWAIMorihiro SAITOJun KUWANO...
    459-462页
    查看更多>>摘要：The trirulile oxides MTa_2O_6 (M=Co,Ni,Mg) [MTs] and the substitution products M_(1-x)N_xTa_(2-y)L_yO_6 (N=Mn, L=Sn,Ti,Zr) [M_(1-x)N_xTa_(2-y)L_y] were prepared by a conventional solid-state reaction. The oxygen reduction reaction (ORR) activities were evaluated with the onset potentials (E_(on)) of the ORR currents, the disk current densities (i_D) and the efficiencies (Eff_4) of 4-electron reduction, measured by a rotating ring-disk electrode (RRDE) technique. All the samples showed ORR activities and the E_(on) values were around +0.8 V vs. RHE in 0.1 M KOH. The CoTa_2O_6 electrocatalyst showed the best ORR property of the MTs samples: its Eff_4 value was as high as -80%. With substitution of Ti or Sn, the ORR activities of MgTa_(1.9)T_(0.1)O_6, CoTa_(1.8)Sn_(0.2)O_6 and NiTa_(1.9)Ti_(0.1)O_6 were improved in alkaline solution, compared with those of MTa_2O_6. In acid solution, the same substitution of Ti and Sn resulted in improvement of Eff_4, but no significant improvements of E_(on) and i_D.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Electrical Properties of Pt/Nb-doped SrTiO_3 Schottky Junctions

    Jianyong LiTakeshi OhgakiRyota MatsuokaHideyo Okushi...
    463-466页
    查看更多>>摘要：In this study, we successfully fabricated the Schottky junctions consisting of Pt electrode and high concentration Nb-doped (0.5 wt%) SrTiO_3 (001) single crystal by sputtering process. The carrier concentrations of Nb-0.5wt%-doped SrTiO_3 were determined as 10~(20) /cm~3 order by Hall effect measurement. The electrical properties of junctions were investigated by measuring their current-voltage (I-V), capacitance-voltage (C-V) characteristics at temperature range from 80K to 400K. The hysteresis feature was observed that indicating the alteration of barrier height in junctions especially at lower temperature. The donor concentration and built-in potentials calculated from C~(-2)-V data. showed large discrepancy from Hall effect measurement indicating that the junctions deviate from the ideal Schottky diode model.
      原文链接:
    • NETL
    • NSTL

    Electrochemical Properties of Porous LiAl_xMn_(2-x)O_4 Powders Prepared by Immersion of Li and Al Nitrate Solution to Spherical Mn_2O_3 Powders

    Kazunori NishiwakiTakashi OgiharaShigeru MotohiraTakayuki Kodera...
    467-470页
    查看更多>>摘要：Spherical porous Mn_2O_3 powders were prepared by spray pyrolysis. Li and Al nitrate solution were immersed to porous Mn_2O_3 powders to obtain LiAl_xMn_(2-x)O_4. Homogeneous LiAl_xMn_(2-x)O_4 powders were formed by the calcination at 800℃. SEM observation showed that they had spherical morphology with particle size of about 1μm. XRD revealed that the spinel phase was obtained by heating at 800℃. LiAl_xMn_(2-x)O_4 cathode obtained by this method exhibited higher rechargeable capacity and cycle stability than that obtained by spray pyrolysis. The doping of Al ion was effective for the cycle stability at elevated temperature.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd