Journal of the Ceramic Society of Japan
Online ISSN : 1348-6535
Print ISSN : 1882-0743
ISSN-L : 1348-6535
123 巻, 1438 号
(June)
選択された号の論文の14件中1~14を表示しています
Special Article: The 69th CerSJ Awards for Advancements in Ceramic Science and Technology: Review
  • Hiroaki UCHIYAMA
    2015 年 123 巻 1438 号 p. 457-464
    発行日: 2015/06/01
    公開日: 2015/06/01
    ジャーナル フリー
    In this review, we discuss the spontaneous pattern formation of sol–gel dip coating films induced by solvent evaporation, as a novel patterning technique. Linearly arranged striations and cell-like patterns were obtained upon withdrawing the substrate from the coating solution at increasing withdrawal rates. Such highly ordered micropatterns formed by the Bénard–Marangoni convection mechanism triggered by solvent evaporation. In contrast, dip-coating at rates below 1.0 cm min−1 generated periodic stripe patterns arranged on the surface of the films that were perpendicular to the substrate withdrawal direction. Such a formation design was attributed to the onset of capillary flow of the coating solution at the meniscus induced by solvent evaporation.
Papers
  • Akinori UEHASHI, Hidehiro YOSHIDA, Tomoharu TOKUNAGA, Katsuhiro SASAKI ...
    2015 年 123 巻 1438 号 p. 465-468
    発行日: 2015/06/01
    公開日: 2015/06/01
    ジャーナル フリー
    DC electric fields ranged from 25 to 350 V/cm enhanced the sintering rates of BaTiO3. At the field of 25 V/cm, the sintering densification occurred by field-assisted sintering (FAST), and flash-sintering preceded by FAST was observed at the field strength of more than 75 V/cm. Most of the densification, however, was produced by the FAST process. At high field strength of more than 250 V/cm, the sintering densification was not finished owing to discharging during the flash-sintering. By means of FAST process at 100 V/cm and the current limit of 100 mA, in contrast, relative density of 97% and a fine grain size about 500 nm were achieved at 1020°C in the present material. The FAST process, where the electric current was set to the transition current between FAST and flash-sintering, is highly effective to fabricate uniform and fine grained BaTiO3 polycrystal.
  • Yu-Chun CHEN, Hsiao-Ya HUANG, Hsiu-Mei LIN, Fu-Yin HSU, Yu-Ping SU, De ...
    2015 年 123 巻 1438 号 p. 469-475
    発行日: 2015/06/01
    公開日: 2015/06/01
    ジャーナル フリー
    Sea urchin Tripneustes gratilla is one of the valuable fishery products in Taiwan. The edible part of sea urchin is about 10% and the rest is regarded as waste. In this study, sea urchin shell was used here as an ingredient to synthesize magnesium substituted beta-tricalcium phosphate (β-TCMP). Shell powder of the echinoid Tripneustes gratilla was converted by hydrothermal reaction at 180°C for 24 h (referred as SU-180-24 product), and calcinated into tablet at 800°C for 4 h to form the target ingredient (SU-800-4 product). Then these products were tested for chemical composition analysis and bioassays. These products are confirmed to be rich in magnesium and constitute as β-TCMP. Results from bioassays showed that SU-180-24 and SU-800-4 products increased cell viability in human osteosarcoma cell (MG-63). Alkaline phosphatase (ALP) activity of MG-63 cell cultured with SU-800-4 tablet also showed significant increase when compared to commercial β-TCMP. It indicated that sea urchin’s β-TCMP materials including SU-180-24 and SU-800-4 products exhibited the potential for applying as the bone graft material.
  • Nai-Chuan CHUANG, Jyi-Tsong LIN, Huey-Ru CHEN
    2015 年 123 巻 1438 号 p. 476-479
    発行日: 2015/06/01
    公開日: 2015/06/01
    ジャーナル フリー
    This paper presents the co-firing behavior and interfacial structure of Ni–Zn–Cu ferrite/Al2O3–SiO2–B2O3 glass-ceramic composites. An effective multilayered structure is proposed to prevent the camber and crack problem due to the shrinkage behavior and thermal expansion coefficient difference during the sintering process. Bi2O3 not only plays a role as a sintering aid to reduce the sintering temperature of Ni–Zn–Cu ferrite but it also diffuses into Al2O3–SiO2–B2O3 glass-ceramic forming a stronger bonding at the interface after sintering.
  • Sangram MAZUMDER, Wei ZHAO, Jung Gyu PARK, Naboneeta SARKAR, Sukyoung ...
    2015 年 123 巻 1438 号 p. 480-484
    発行日: 2015/06/01
    公開日: 2015/06/01
    ジャーナル フリー
    In this study, consolidated zeolite crystal coated porous ceramic foams containing a large quantity of carbon nanotubes (CNTs) within micro-metre sized pores were prepared. An alumina-silica porous ceramic body, having an average pore size of less than 100 µm, was produced by the direct foaming technique. Well-shaped zeolite crystals having an average size of 180 nm were synthesized and homogeneously coated on the porous ceramic body by an in situ process. An Fe-supported zeolite/ceramic matrix, which is used for CNT synthesis, was prepared using ion-exchange by immersing the zeolite-coated porous ceramic body into FeCl2 aqueous solution. The CNTs were synthesized by a catalytic chemical vapour deposition (CCVD) process for four different reaction times. Both acicular-shaped and randomly bundled networks of multi-walled carbon nanotubes (MWCNTs) were synthesized using these different reaction times. Moreover, the yield of CNTs produced showed a tendency to increase with increasing reaction time.
  • Jinglin LIU, Chengde GAO, Pei FENG, Tao XIAO, Cijun SHUAI, Shuping PEN ...
    2015 年 123 巻 1438 号 p. 485-491
    発行日: 2015/06/01
    公開日: 2015/06/01
    ジャーナル フリー
    Bioactive glasses have wide application prospects in bone replacement and regeneration owing to the unique osteoconductivity and osteostimulativity. However, the high brittleness and poor compressive strength limit their applications in load-bearing positions. In this study, multi-wall carbon nanotubes (CNTs) were used to toughen bioactive glass (13–93 glass), and their nanocomposite scaffolds were fabricated by selective laser sintering. The effect of CNTs amount (1–5 wt.%) on mechanical properties of the scaffolds was investigated. The results showed that CNTs were effective to improve the mechanical properties of the nanocomposite scaffolds by virtue of the toughening mechanisms of bridging, pull-out and crack deflection. The optimum compressive strength and fracture toughness reached to 37.32 MPa and 1.58 MPa·m1/2, respectively, by adding the appropriate amount of CNTs (3 wt.%). In addition, the bone-like hydroxycarbonate apatite (HCA) layer was formed on the surface of the nanocomposite scaffolds after immersion in simulated body fluid (SBF) for 10 days. And the cell culture test showed that the scaffolds should have good cytocompatibility. The research indicated that the 13–93 glass-CNTs nanocomposites scaffolds are promising candidates for bone tissue engineering applications.
  • Masao KOMATSU, Akio OCHI
    2015 年 123 巻 1438 号 p. 492-500
    発行日: 2015/06/01
    公開日: 2015/06/01
    ジャーナル フリー
    Ceramics were formed by the addition of magnesia to zirconia in the composition range of 0 to 50 mol %, and these ceramic materials were liquid quenched using an infrared image furnace and a twin roll process. The composition and structure of the liquid-quenched film samples were examined using X-ray diffraction and transmission electron microscopy. The results confirmed the formation of a high-temperature metastable phase (t′-phase) in ZrO2-9 mol % MgO partially stabilized zirconia (PSZ). The t′-phase that formed underwent a transition to the stable tetragonal phase (t-phase) during a suitable annealing treatment, but it was found not to undergo a phase transformation to the monoclinic phase (m-phase) in the presence of external stress. The t′-phase was confirmed to have three variants.
  • Eiki NIWA, Tsubasa SATO, Yuki WATANABE, Yuichiro TOYOTA, Yoshikiyo HAT ...
    2015 年 123 巻 1438 号 p. 501-506
    発行日: 2015/06/01
    公開日: 2015/06/01
    ジャーナル フリー
    Dependence of crystal symmetry, electrical conductivity, chemical state of Fe and optical property of LnFeO3 (Ln: La, Pr, Nd, Sm) on kinds of Ln3+ was investigated. All the LnFeO3 showed orthorhombic structure, with which order of high crystal symmetry was LaFeO3 > PrFeO3 > NdFeO3 > SmFeO3. Using tolerance factor, the order was successfully explained. The electrical conductivity of all the specimens could be explained by using small polaron hopping model. With increasing crystallite symmetry, electrical conductivity increased and activation energy for hopping conduction decreased. This can be ascribed to larger overlapping of Fe3d orbital and O2p orbital on nearly linear Fe–O–Fe bond in LnFeO3 with higher crystal symmetry. The larger overlapping of Fe3d orbital and O2p orbital in LnFeO3 with higher crystal symmetry can also be an origin of larger spin–spin interaction detected by Mössbauer spectroscopy and larger optical band gap observed by diffuse reflectance spectroscopy. Since chemical state of Fe, evaluated by Mössbauer spectroscopy, in LnFeO3 is fundamentally constant at +3 regardless of kinds of Ln3+, carrier concentration of LnFeO3 was revealed to be constant. It is concluded that the predominant factor which determine the electrical property of LnFeO3 is mobility affected by crystal symmetry.
  • Takuya HASEGAWA, Natsuki SATO, Sun Woog KIM, Tadashi ISHIGAKI, Kazuyos ...
    2015 年 123 巻 1438 号 p. 507-511
    発行日: 2015/06/01
    公開日: 2015/06/01
    ジャーナル フリー
    Novel Ln3+-doped (Ln3+ = Tb3+ and Eu3+) and Eu3+, Bi3+ co-doped Ca3Y3Ge2BO13 phosphors were synthesized by a conventional solid-state reaction method. Tb3+- and Eu3+-doped phosphors showed strong narrow green and red emission due to 4f intra-shell transitions of the Tb3+ or Eu3+ ions under the excitation at 254 nm. Bi3+ co-doped Ca3Y3Ge2BO13:Eu3+ phosphor has a new broad strong excitation band appeared at around 302 nm due to 1S03P1 transition of Bi3+, and presents red emission owing to 4f-4f transition of Eu3+ under excitation at 302 nm.
Note
  • Yuichi TOMINAGA, Kimiyasu SATO, Xinlei YAN, Daisuke SHIMAMOTO, Yusuke ...
    2015 年 123 巻 1438 号 p. 512-515
    発行日: 2015/06/01
    公開日: 2015/06/01
    ジャーナル フリー
    A wet-rotating disc milling was used as a novel method to investigate the exfoliation of laminated hexagonal boron nitride (h-BN) particles. The sedimentation test after the milling showed that the relative packing density of h-BN particles treated by the wet-rotating disc milling was much low compared to non-milled h-BN particles. Also, the particle size distributions showed that the particle size of exfoliated h-BN particle was relatively as similar as the initial particle size. Furthermore, SEM images of wet-rotating disc milled h-BN particles showed that the decrease of h-BN thickness was affected to the relative packing density after sedimentation test. The average aspect ratio of prepared h-BN particles was increased 1.8 times as compared to pristine h-BN particles. The wet-rotating disc milling process led to exfoliation of laminated h-BN particles without reducing the particle size and destroying the crystal structure. Moreover, the relative packing density of exfoliated h-BN particles was affected to rotation speed, number of pass, and distance between two rotation discs. Therefore, it was found that the exfoliation of laminated h-BN particles effectively was progressed by wet-rotating disc milling.
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