Journal of the Ceramic Society of Japan
Online ISSN : 1348-6535
Print ISSN : 1882-0743
ISSN-L : 1348-6535
125 巻, 7 号
(July)
選択された号の論文の15件中1~15を表示しています
Full paper
  • Ken'ichiro KITA, Naoki KONDO
    2017 年 125 巻 7 号 p. 543-546
    発行日: 2017/07/01
    公開日: 2017/07/01
    ジャーナル フリー
    This paper describes a novel method for joining aluminum and silicon nitride using a polysiloxane. The X-ray diffraction patterns suggested that the polysiloxane surrounded by aluminum and silicon nitride powders could be transformed into silicon, aluminum silicate, and SiAlON. Neither cracks nor exfoliation between aluminum and silicon nitride could be observed, and they were joined through the joining layer. Moreover, detailed investigation of the layer by transmission electronic microscopy, selected area electron diffraction, and point analysis energy-dispersive X-ray spectroscopy suggested that the layer consisted of amorphous and nano-sized polycrystalline particles containing aluminum, silicon, nitrogen, and oxygen. The minimum thickness of the layer was less than 10 nm. The bending strength of the joined sample was 204 MPa and the fracture point was the joining layer between aluminum and silicon nitride.
Special Articles: The 71st CerSJ Awards for Advancements in Ceramic Science and Technology: Review
  • Takashi TERANISHI
    2017 年 125 巻 7 号 p. 547-551
    発行日: 2017/07/01
    公開日: 2017/07/01
    ジャーナル フリー
    The frequency response of the permittivity of oxides is described by the dielectric dispersion of four contributions: the interfacial, dipole, ionic, and electronic polarizations. Our recent studies related to the broadband dielectric and conductivity spectroscopy of oxides are reviewed herein. Two methods, i.e., the micro-sized planar electrode and ring resonator techniques, were developed to measure the microwave dielectric properties of specimens having a large permittivity. Using these methods, we developed the complex permittivity of a paraelectric SrTiO3 (ST) single crystal up to a few GHz. We also investigated the polarization contribution to the microwave tunability, T, of ferroelectric Ba0.8Sr0.2TiO3 (0.8-BST). The apparent tunability of 0.8-BST was determined by the domain wall density; a higher domain wall density resulted in a larger dipole polarization. A modified Kohlrausch–Williams–Watts model was used for the dipole relaxation function. Ionic polarization was analyzed using the four-parameter semi-quantum phonon dispersion model. The dielectric function combining these two relationships was used for broadband spectroscopic analysis of the dielectrics. The dipole and ionic polarizations and electronic contributions were simultaneously quantified for the ferroelectric BaTiO3 ceramic and ST single crystal. The broadband conductivity spectrum of 8 mol% yttria-stabilized zirconia, a fast oxygen-ion conductor, was also acquired to quantify all conduction contributions, i.e., the interfacial, grain boundary, and bulk contribution.
  • Akira MIURA
    2017 年 125 巻 7 号 p. 552-558
    発行日: 2017/07/01
    公開日: 2017/07/01
    ジャーナル フリー
    Nitrides and oxynitrides exhibit great potential for novel material development, since their electronic structures can be controlled by tuning the amounts of air-abundant nitrogen and oxygen elements therein. However, the above control methods still need to be developed, and the crystal and electronic structures of the produced nitrides/oxynitrides need to be understood. Herein, I summarize the recent progress in nitride and oxynitride synthesis, highlighting novel low-temperature nitridation of oxides by molten NaNH2, and attempt to rationalize the crystal and electronic structures of nitride and oxynitrides. Moreover, I describe how the catalytic activity of manganese oxynitrides in the oxygen reduction reaction can be enhanced by tuning their nitrogen content and thus their electronic structures.
Full papers
  • Krisana KOBWITTAYA, Yushi OISHI, Toshio TORIKAI, Mitsunori YADA, Takan ...
    2017 年 125 巻 7 号 p. 559-564
    発行日: 2017/07/01
    公開日: 2017/07/01
    ジャーナル フリー
    Ho3+ and Yb3+ co-doped ZnO–TiO2 composites were prepared by conventional solid-state reaction method and their upconversion (UC) luminescence characteristics were evaluated. The effects of ZnO/TiO2 mixing ratio, and Ho3+ and Yb3+ concentrations were investigated. The ZnO–TiO2 composite products fired at 1200°C consisted of Zn2TiO4, TiO2, RE2Ti2O7, and RE2TiO5 (RE = Ho3+ and/or Yb3+) phases. Bright UC emission peaks centered at 542 and 670 nm wavelengths from the Ho3+ ions were observed. The UC emission intensity of the product was changed by varying ZnO/TiO2 mixing ratios, Ho3+ and Yb3+ concentrations. The optimum condition for the brightest UC emission was 1ZnO:1TiO2 doped with 0.05 mol % Ho3+, 9 mol % Yb3+ fired at 1200°C for 4 h. The pump power dependent studies demonstrated that UC emissions related to the two-photon process and UC mechanisms were suggested and discussed in detail.
  • Kazuyuki SUZUKI, Atsuya TOWATA, Yoshiaki KINEMUCHI, Daisuke NAGAI, Mas ...
    2017 年 125 巻 7 号 p. 565-568
    発行日: 2017/07/01
    公開日: 2017/07/01
    ジャーナル フリー
    Highly dispersed core–shell α′′-Fe16N2/SiO2 particles were prepared using hydroxyapatite (HAp) as the sintering prevention layer. HAp was effective as anti-sintering agent, and could be dissolved by solutions with wide pH range. The α′′-Fe16N2 phase was formed by reduction and nitridation, in spite of the presence of SiO2 and HAp. HAp was effective to prevent the aggregation of the core–shell α′′-Fe16N2/SiO2 particles resulted from the elimination of the surface Si–OH of silica shell layer. The HAp was successfully removed using the citric acid without the degeneration of the SiO2 shell layer and α′′-Fe16N2 core particles.
  • Sadaaki SAKAMOTO, Seiji FUJITA, Yasutaka SUGIMOTO, Nobuhiko TANAKA
    2017 年 125 巻 7 号 p. 569-573
    発行日: 2017/07/01
    公開日: 2017/07/01
    ジャーナル フリー
    We developed a structure of a mechanical-strength-enhanced low-temperature co-fired ceramic (LTCC) substrate using two LTCC materials with different thermal expansion coefficients (TECs). In this structure, the top and bottom surface layers are made of a material with a lower TEC and the internal layers are made of another material with a higher TEC. Because compressive stress was thought to be exerted in the surface layer due to the differences in the TECs between two materials, it was expected that the compressive stress would reinforce the surface. We found that the bending strength of the substrate was more than 400 MPa and considerably higher than that of each material. The results of stress analysis using the finite element method indicate that the fracture stress of the internal layer considerably exceeded the mechanical strength of the material comprising the internal layer. This is thought to be the cause of mechanical strength enhancement. Therefore, this proposed structure is promising for thinner multilayer substrates.
  • Tomoya GAKE, Kakeru NINOMIYA, Kenji OBATA, Masao ARAI, Shigenori MATSU ...
    2017 年 125 巻 7 号 p. 574-578
    発行日: 2017/07/01
    公開日: 2017/07/01
    ジャーナル フリー
    The first-principles energy band calculation for M3Ta6Si4O26 (M = Ba, Sr) with optimized structure is performed using the Tran-Blaha (TB) exchange potential combined with correlation potential from the local density approximation (LDA). The theoretical minimum band gaps of Ba3Ta6Si4O26 and Sr3Ta6Si4O26 are estimated to be 4.39 and 4.46 eV, respectively. These results are in large contrast to the underestimation based on the generalized gradient approximation calculation. The band gaps of M3Ta6Si4O26 (M = Ba, Sr) hardly changed with the spin-orbit interaction. The main conduction band can be divided into two energy regions near 7.6 eV due to the octahedral crystal-field splitting based on the interaction between Ta-d and O-p states. On the other hand, the main valence band in the energy range of −5.3 to 0 eV is constructed from O-p states, where the Ta-d states hybridize strongly with the O-p states. The optical properties of M3Ta6Si4O26 (M = Ba, Sr) are predicted from the complex dielectric function ε(ω) = ε1(ω) + iε2(ω). Polarized peaks in the z-direction appear at 5.5 and 6.4 eV for Ba3Ta6Si4O26, 5.6 and 6.6 eV for Sr3Ta6Si4O26 in the ε2(ω) function, respectively. The absorption coefficient estimated from the TB-LDA is very similar to the experimental result obtained in the literature.
  • Naga Vijaya Lakshmi MANCHINASETTY, Taira SATO, Mamoru AIZAWA, Sridhara ...
    2017 年 125 巻 7 号 p. 579-583
    発行日: 2017/07/01
    公開日: 2017/07/01
    ジャーナル フリー
    Influences of combined supplementation of calcium citrate (Ca–Cit) and calcium carbonate (CaCO3) on the hydroxyapatite/collagen (HAp/Col)–sodium alginate (Na–Alg) paste (HAp/Col paste) were investigated. Supplementation amounts of Ca–Cit and CaCO3 were denoted as Nx, where N is a multiplication number to Ca2+ ion amounts for the equivalent reaction with Na–Alg obtained previously. Combined supplementation of 10x Ca–Cit and 2x CaCO3 improved the anti-washout property at a washout ratio of 2.42 ± 0.72% and pH maintenance at 7.34 ± 0.08, these values were better than the best HAp/Col paste using Ca–Cit (5.91 ± 2.73% washout ratio and 6.72 ± 0.06 of pH). This is due to coordinate effects of initial washout inhibition by weak but rapid formation of long-range network by citric acid followed by long term anti-washout inhibition by strong but slow network formation by Ca2+ ions. The paste also showed good cytocompatibilty that MG63 cells proliferated with the culture time without any significant difference with the HAp/Col dense bodies. The HAp/Col paste is expected to be utilized in minimally invasive surgery of bone defect.
  • Congxu ZHU, Xiwang WU, Xuliang ZHU, Yabing WANG, Xinfang LIU, Jiyao LI ...
    2017 年 125 巻 7 号 p. 584-587
    発行日: 2017/07/01
    公開日: 2017/07/01
    ジャーナル フリー
    A unique preparation method for copper-red glaze is investigated by using nano-SiC to reduce CuO nano-materials in an oxidizing environment. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and fourier-transform infrared spectroscopy were used to investigate the influence of nano-SiC content on the crystalline phase evolution and phase separation of the copper-red glaze. The results indicate that the added nano-SiC can promote the crystallization of SiO2 and increase the average diameter of phase separation in the glaze. The color of the samples containing 0.01 to 0.3 mass % SiC become redder in hue after calcination in an oxidizing atmosphere. Interestingly, the structural color forms due to Rayleigh scattering, which may account for the slightly blue hue of glaze-fired samples containing different amounts of nano-SiC. The viscosity of the molten glazes decreases with increasing nano-SiC content. A possible in-situ reductive mechanism is proposed to explain how the red color is generated and changes with the amount of nanosized SiC.
Technical report
  • Naoki KONDO, Ken’ichiro KITA, Takaaki NAGAOKA
    2017 年 125 巻 7 号 p. 588-590
    発行日: 2017/07/01
    公開日: 2017/07/01
    ジャーナル フリー
    The effect of adding cellulose nanofibers (CNFs) to a silicon nitride slurry was evaluated. The addition of small amounts of CNFs drastically increased the viscosity of the silicon nitride slurry. Pouring the slurry with CNFs into a non-water absorptive mold, followed by natural drying, yielded a silicon nitride green body. Sintered silicon nitride was successfully fabricated via de-binder treatment and sintering of the green body. The sintered silicon nitride had a density of 3.142 × 103 kg m−3, and a microstructure with rod-like grains and a glassy grain boundary phase. The flexural strength of the sintered body was 595 MPa. These properties were comparable to those of silicon nitride fabricated from a slurry without CNFs.
Note
  • Sunao KAMIMURA, Chao-Nan XU, Hiroshi YAMADA, Gerard MARRIOTT, Koji HYO ...
    2017 年 125 巻 7 号 p. 591-595
    発行日: 2017/07/01
    公開日: 2017/07/01
    ジャーナル フリー
    Inorganic phosphors that emit near-infrared (NIR) light are highly valued as fluorescent probes for in vivo imaging of biological tissue. NIR-imaging, however, is limited by the paucity of probes that emit over the NIR-II window (1000–1400 nm). We are interested in exploring the potential of double-layered perovskite structures harboring lanthanide ions as NIR-II fluorescent probes. In this report, we describe the synthesis, and characterization of the photoluminescence, afterglow and thermo-luminescence of Nd3+-doped Sr3Sn2O7 together with an analysis of its structural properties. Sr3Sn2O7:Nd3+ has a double-layered perovskite structure with oxygen octahedral tilt and rotation, which leads to an intense NIR-II luminescence from 4f–4f transition in Nd3+ ions; the intensity of NIR-II photoluminescence of Sr3Sn2O7:Nd3+ is 102 times higher than that of an ordinary perovskite structure, namely SrSnO3:Nd3+. Moreover, we show the intra-layer planar defect in Sr3Sn2O7:Nd3+ contributes to the long-lived NIR-II afterglow. Finally, we show time-resolved imaging of the long-lived NIR-II fluorescence of Sr3Sn2O7:Nd3+ generate high-contrast images of probes embedded within a model tissue.
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