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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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    Study on Improvement of Oxidation-resistant Capability of Metal-silicide thin Film and Application to Heater

    Teppei HayashiMasashi SatoShinzo Yoshikado
    169-172页
    查看更多>>摘要：Thin films of Si-added-MoSi_2 were deposited on Si_3N_4 or alumina substrate using an RF magnetron sputtering with a target made of MoSi_2 and Si powders. The thin film consisted of a mixture of Si and MoSi_2. The resistance of MoSi_2-thin-film heaters fabricated using Si_3N_4 substrate heated for a long time in air increased with increasing heating-time at temperatures near 420℃ due to generation of MoO_3, which is an insulator, in thin film due to the oxidation of Mo in MoSi_2. On the other hand, oxidation-resistant capability of thin-film heater fabricated by adding Si to MoSi_2 was drastically improved compared with MoSi_2 thin-film heater, because Si particles or the Si layer on a MoSi_2 particle prevented the oxidation of MoSi_2. The oxidation-resistant capability was excellent in air at high temperatures near 480℃ for a long heating-time exceeding 950h.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Preparation of Thin Films of TiO_2-Nanoparticles Using Electrophoresis Deposition Method

    Kazuatsu ItoYuuki SatoMotonari AdachiShinzo Yoshikado...
    173-176页
    查看更多>>摘要：TiO_2-nanoparticles of anatase-type were synthesized and deposited using the electrophoresis deposition method. All of TiO_2-nanoparticles were positively charged in colloidal aqueous solution and were attracted toward ITO glass as the negative electrode as same as nanoparticles (P25) whose diameter is larger than that of TiO_2-nanoparticles. Many of the TiO_2-nanoparticles were connected with each other and formed clusters, although single TiO_2-nanoparticles were also observed. The cracks generated in the thin film with increasing the deposition time and thin film was flaked off from substrate. High optical transparency TiO_2-nanoparticles-thin film without cracks was deposited when the deposition time was short. Moreover, the thickness of TiO_2-thin film, which has high optical transparency and no cracks, could be increased using mixture of TiO_2-nanoparticles and P25.
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    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Monte Carlo Investigation of Ferroelectric Properties in Thin Films

    Yongyut Laosiritaworn
    177-180页
    查看更多>>摘要：In this work, the ferroelectric hysteresis in thin films was investigated with Monte Carlo simulation using the DIFFOUR Hamiltonian and the Metropolis algorithm. The field frequency, the filed amplitude and the thickness dependence of hysteresis properties were found. For instance, at high enough field, the area increases, maintains and reduces with increasing frequency. However, with increasing the film's thickness, the area increases over the whole considered frequencies, and the frequency at maximum area shifts to a lower frequency due to the stronger ferroelectric coupling in thicker films. In addition, the scaling relation among the hysteresis properties, the film's thickness and the field parameters in the power law form were also investigated, where the scaling exponents were compared and discussed with experiments on thin ferroelectric films.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Li(Ga_(1-x)M_x)O_2 (M: B or Al) single crystals grown by Floating zone method

    Hideo KimuraRumi TanahashiKoji Maiwa
    185-188页
    查看更多>>摘要：Li(Ga_(1-x)M_x)O_2 (M: B or Al) single crystals are grown by Floating zone method. These crystals are characterized from the viewpoint of the substitution of M, such as lattice parameter (lattice volume) change, piezoelectric properties and nonlinear optics. The lattice volume is decreased with the increase of Al content for Al-substitution largely, but the change is a little for B-substitution.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    CRYSTALLIZATION BEHAVIOR OF FERROELECTRIC GLASS-CERAMICS OF THE Na_2O-Nb_2O_5-Al_2O_3-SiO_2 SYSTEM CONTAINED TiO_2

    Anuson NiyompanKanita SrisuratRungnapa Tipakontitikul
    189-192页
    查看更多>>摘要：The ferroelectric glass-ceramic of the composition Na_2O-Nb_2O_5-Al_2O_3-SiO_2 was prepared by controlling crystallization of the glass that added with small amount of TiO_2. The effect of TiO_2 content on crystallization behavior and the dielectric property were determined. X-ray diffraction studied indicated that NaNbO_3, NaNbO_8 and a compound of alkali alumino silicate composition were readily formed in the as-quenched glass as the product of phase separation. After treatment at 700℃ for various times, NaNbO_3 volume fraction was found to increase with time. Crystalline size of the NaNbO_3 was lower than 300 nm and it was developed with treatment time. Presence of TiO_2 had considerably effect on NaNbO_3 volume fraction when treatment time shorter than 1.0 h. The dielectric response of the glass-ceramic samples was found to arise from all contributions of crystalline phases and glass matrix responds.
      原文链接:
    • NETL
    • NSTL

    Zinc Self-diffusion in Isotopic Heterostructured Zinc Oxide Thin Films

    Kenji MATSUMOTOYutaka ADACHITakeshi OHGAKIIsao SAKAGUCHI...
    193-196页
    查看更多>>摘要：Zinc isotopic heterostructured zinc oxide thin films of ~(64)ZnO/~(68)ZnO/~(64)ZnO were synthesized using pulsed laser deposition. The pulsed laser was first irradiated onto a polycrystalline target of ~(64)ZnO to deposit the ~(64)ZnO layer, then onto the ~(68)ZnO target to prepare the ~(68)ZnO layer and finally, the ~(64)ZnO target was used again. The ~(64)ZnO/~(68)ZnO/~(64)ZnO layered thin film was thus obtained. The thin films were annealed at various diffusion annealing temperatures. Diffusion profiles of the zinc isotopes due to the annealing were evaluated using secondary ion mass spectrometry (SIMS). The diffusion coefficients were slightly higher near the interface between the thin film and the substrate (the inner region) compared to the near surface (the outer region).
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Observation of Diffusion Behavior in Al-implanted ZnO Single Crystal

    Tsubasa NakagawaIsao SakaguchiKenji MatsumotoMasashi Uematsu...
    197-200页
    查看更多>>摘要：Diffusion behaviors of aluminum (Al) in zinc-oxide (ZnO) single crystals were measured by means of ion implantation technique and SIMS depth profiling. It was found that Al concentration profile had a peculiar shape with a constant-concentration region and a steep tail, which was also found in profiles of other donors such as Ga and In. Detailed analysis of the profiles revealed that the diffusivity of Al was proportional to the square of Al concentration and its intrinsic diffusivity was much smaller than previously reported values. Oxygen diffusion experiments were also performed and the implantation of Al ions enhanced the oxygen diffusion coefficients by about 20 times. This result indicates that oxygen interstitial diffusion occurs in n-type ZnO.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Redistributing unintentional defects induced by heavy ion implantation in ZnO ceramics

    Isao SakaguchiTsubasa NakagawaKenji MatsumotoSyunichi Hishita...
    201-204页
    查看更多>>摘要：The relationship between the defect structure and luminescence property of ZnO ceramics implanted with Ar of 2×10~(15) - 60×10~(15) ions/cm~2 was studied. After annealing, the heavy dose-implanted sample (Ar ≥ 30×10~(15) ions/cm~2) was characterized by a luminescence peak at the 730-nm wavelength. Defects in the implanted region formed voids during post-annealing. Oxygen tracer experiments indicated that grain boundary diffusion in the implanted region was enhanced significantly.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Radiation of X-rays in Low-Pressure Gas Using LiNbO_3 Single Crystal

    Shinji FukaoYoshikazu NakanishiTadahiro MizoguchiYoshiaki Ito...
    205-208页
    查看更多>>摘要：The gas pressure and the types of ambient gas dependence of X-ray intensity were investigated for LiNbO_3 single crystals polarized in the c-axis direction at pressures of approximately 1 to 30 Pa. The integrated X-ray intensity showed a local maximum value at the pressure P_(max). P_(max) moved to the high-pressure side in the ambient with a large first ionization energy. P_(max) was proportional to the Boltzmann factor using the first ionization energy of each ambient gas molecule. The X-ray intensity was approximated using the quadratic function, which was convex upward for the pressure. It was found that one of the causes of the decrease in X-ray intensity on the pressure side higher than P_(max) was the adsorption of positive ions on the crystal electric surface.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Effect of Zr-addition on Electric Degradation Characteristics of ZnO Varistors

    Yuji AkiyamaMasayuki TakadaAi FukumoriYuuki Sato...
    209-212页
    查看更多>>摘要：ZnO varistors of the excellent tolerance characteristics for electrical degradation were made by adding Bi_2O_3-MnO_2-Co_3O_4-Cr_2O_3-SiO_2-Sb_2O_3-NiO in ZnO. The tolerance characteristics for electrical degradation were evaluated by changing amount of ZrO_2-additive. The evaluation methods are voltage-current characteristics, X-ray diffraction, scanning electron microscope, and energy dispersion X-ray spectroscopy. Monoclinic and tetragonal ZrO_2 and the compounds originated in Zr were observed at both grain boundaries and triple points. Moreover, the compounds originated in both Zr and Sb improved the tolerance characteristics for electrical degradation. On the other hand, especially monoclinic ZrO_2 deteriorated the tolerance characteristics for electrical degradation. It is one key factor of the improvements of the tolerance characteristics for electrical degradation that the mobility of oxide ions or interstitial Zn~(2+) ions was hindered by forming the compounds contained Zr, Sb, Si, and, Bi atoms.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd