Journal of the Ceramic Society of Japan (日本セラミックス協会学術論文誌)
Online ISSN : 1882-1022
Print ISSN : 0914-5400
ISSN-L : 0914-5400
98 巻, 1134 号
選択された号の論文の20件中1~20を表示しています
  • 堺 一男, 末永 知子, 佐多 敏之
    1990 年 98 巻 1134 号 p. 121-125
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    The distribution for the respective constituent elements according to depth was examined in the disintegration of a superconducting oxide Ba2EuCu3O7-x in different humidities at 25°C. Two kinds of segregation in the respective elements were observed during the disintegration: one was a small periodical segregation with about 10% variation of Ba content and the other was a large random one with about 30-50% variation. The time at which the small segregation appeared was closely correlated to the disintegration of the superconducting oxide. The concentrational variations of Ba and Eu elements in the large segregation were in an opposite manner.
  • 平田 好洋, Ilhan A. AKSAY, 菊池 良一
    1990 年 98 巻 1134 号 p. 126-135
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    Theoretical analysis on the pore structure in a powder compact was made with an F. C. C. model of hierarchically clustered spherical particles. The derived theory can reveal the pore volume and pore size distribution of 1st generation pores (contained within clusters of primary particles) and 2nd or 3rd generation pores (contained among the 1st or 2nd generation particle clusters). The calculated results concluded that reduction in the size of particle cluster leads to the formation of a sinterable green compact with a narrow pore size distribution of small average size and high packing density. The derived concept on the pore structure was compared with the pore size distributions of the green compacts consolidated by filtration of colloidal suspensions of spherical mullite particles (average size 65nm). A good agreement was recognized between the theoretical prediction and experimental results.
  • 武部 博倫, 吉原 直樹, 森永 健次
    1990 年 98 巻 1134 号 p. 136-143
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    To fabricate the yttria-stablized zirconia (YSZ) films for solid oxide fuel cell by the slip casting, viscosity of YSZ slips and sintering property of green bodies have been investigated. Chlorine in as-received YSZ powders was removed as Cl- ion by repetitive laundering of admixing distilled water. The sintering property of as-received YSZ powders was superior to that of laundered ones, because YSZ particles were condensed in the laundering process. Both as-received and laundered YSZ particles were stabilized in the slip with a deflocculant containing NH4+ salt of polyacrylic acid as a major component. For some slips the square of thickness of casting layer, L2, was proportional to the casting time, t. Casting rate consant, L2/t, was increased with increasing concentration of YSZ powders in the slips. The thickness of casting layer for fabricating YSZ films could be controlled by the casting data of YSZ slips. The relative densities of sintered YSZ specimens were 92 and 96% at sintering temperatures of 1300° and 1500°C, respectively. Dense YSZ films were fabricated by slip cast, and sintered without pressure at 1500°C. The I-V characteristics of the flat thick film type solid oxide fuel cell based on the YSZ electrolyte film of 140μm thick, La0.6Sr0.4MnO3 cathode and NiO+YSZ anode was excellent, and the power of this cell was about 450mW/cm2.
  • 杉江 他曽宏, 奥野 仁樹, 藤井 知
    1990 年 98 巻 1134 号 p. 144-149
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    Sr0.5Ba0.5Nb2O6 (SBN) single crystal with various oxide fluxes was grown by flux cooling method. The results were as follows.
    (1) SBN single crystal was only grown in binary of SrB4O7-BaB4O7 flux. The maximum size of the obtained SBN single crystal was over 1mm.
    (2) The SBN single crystal obtained in binary flux had following properties. Curie point was 95°C. Electric resistivity was 3.0×108Ω⋅cm at room temperature. Activation energy was 0.97eV in ferroelectric phase and 0.16eV in paraelectric phase.
    (3) From additive of MgO in binary flux, SBN single crystal was changed to colorless and transparent. For the lattice constant, a axis was increased but c axis was decreased in dependence on amount of added MgO. Electric resistivity of the MgO doped SBN crystal was higher value than that of the MgO undoped SBN crystal.
    (4) SBN single crystal was not grown in respective simple oxide fluxes. Pb5Nb4O15 crystal was formed in PbO flux. Ba3Nb10O28 and Sr2Nb2O7 crystals were formed in CuO flux. Na0.5Sr0.25NbO3 crystal was formed in Na2B4O7 flux.
  • 市原 高史, 鶴見 敬章, 浅賀 喜与志, 李 卿喜, 大門 正機
    1990 年 98 巻 1134 号 p. 150-155
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    PZT crystalline powders with different grain sizes and morphologies were synthesized by hydrothermal reactions below 200°C using KOH as a reaction-accelerator. The grain size of the PZT powders decreased with increasing reaction temperature. PZT powders with a cubic shape were obtained when the KOH concentration was low. Addition of about 22% excess Pb to the starting solution was necessary to obtain stoichiometric PZT powders. The ceramics prepared from cubic powders with the large grain sizes had low coercive fields, and showed relatively high electromechanical coupling factors even with the low electric field for poling. The ceramics prepared from powders of small grains did not have a high coupling factor, but the mechanical quality factor (Qm) was high.
  • 鎌田 喜一郎, 斎藤 則夫, 林 範行, 田辺 伊佐雄, 森山 実
    1990 年 98 巻 1134 号 p. 156-160
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    Amorphous SiCx (x≤0.85) films thicker than 1μm were prepared by a magnetron-type reactive sputtering using a Si target and CH4 gas. Microhardness (Hv), internal stress and adhesion strength by the scratch test were measured. The microhardness of SiC0.85 films prepared by this technique was intrinsically determined to be 22GPa for 6μm-thick specimens. The microhardness for 1μm-thick SiCx films also showed a relatively small increase with the carbon content to that for 6μm-thick SiCx films. Compressive stresses (<3.2GPa) were observed in all SiCx films obtained in this work. The internal stress in the SiCx films (0.2μm thick) was well correlated with the crack length induced with a Vickers indenter as a result of the thin-layer surface stress analysis. The critical load of the SiCx films (1μm thick) decreased with increasing internal stress.
  • 高橋 達人, Dinesh K. AGRAWAL, Rustum ROY
    1990 年 98 巻 1134 号 p. 161-167
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    The phase relationships along binary join of SiO2-AlPO4 were investigated up to 400°C using several starting materials made by a partial solution route. Precursors used were boehmite (AlOOH), H3PO4, non crystalline silica (Ludox, Cab-O-Sil), and quartz. Studies up to 400°C showed that SiO2, AlPO4, and its hydrate were the only crystalline and non-crystalline phases present along the binary join, and no substantial crystalline solution of any ternary phase was observed. Three polymorphic forms of AlPO4, namely, berlinite, tridymite form, and cristobalite form, coexisted at as low as 200°C. The nature of the silica precursors greatly influenced the development of the polymorphic phases of AlPO4. The low quartz precursor suppressed the formation of the cristobalite form of AlPO4 and favored berlinite production. On the other hand, non crystalline silica with a cristobalite-like broad XRD peak suppressed the formation of berlinite and enhanced that of the cristobalite form of AlPO4. The silica precursors acted as structural seeds for the growth of AlPO4. These precursor effects indicate that heteroepitaxy is very significant during the nucleation and growth of AlPO4 phases on the surface of SiO2 particles even in these low temperature reactions. The influence of other precursors and route during the syntheses of AlPO4 and other phases in the SiO2-AlPO4 are discussed.
  • 舟窪 浩, 小林 幹雄, 木枝 暢夫, 加藤 誠軌, 水谷 惟恭
    1990 年 98 巻 1134 号 p. 168-173
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    TaNx-TiN films were prepared on fused silica substrates from the gas mixture of TaCl5-TiCl4-N2-H2 under an atmospheric pressure. The deposition rate, constituent phase, chemical composition and microstructure of the films were investigated as a function of deposition temperature and input gas composition. The films consisted of TaNx and TiN. At the deposition temperature of 900°C, the deposition rate and the composition of TaNx-TiN films were in good agreement with expectations based on each deposition behavior of TaNx and TiN films. On the other hand, at 1000° and 1100°C, the deposition of TaNx was suppressed in TaNx-TiN films compared with the expectation. TaNx-TiN films were consisted of finer particles comparing with TaNx and TiN films.
  • 早川 博, 秋葉 悦男, 水野 正城, 新 重光, 小野 修一郎, 伊原 英雄, 大野 栄三
    1990 年 98 巻 1134 号 p. 174-181
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    A systematic study on superconductivity (Tc) and structural parameters of YBa2-xSrxCu3O7-δ (0≤x≤1.2) has been carried out by the Rietveld analysis of X-ray powder diffraction patterns and by measurement of d. c. electrical resistivity. Single phase samples were obtained in the whole range of x=0-1.0, and Sr atoms were substituted exclusively for the Ba sites in YBa2Cu3O7-δ. Tc and lattice constants decreased linearly with the increase of x from x=0 to 1.2 except for x=1.0. However, a discontinuous raise of Tc and a change in the axial ratio (a/b) was observed at x=1.0. In this structure the Tc's have obvious relations with, the oxygen occupancy in a Cu-O one dimensional chain as well as Ba(Sr)-O and Y-O length. The oxygen atoms in this system play an important role in superconductivity. The orthorhombic-tetragonal phase transition in x=1.0 compound took place at 550°C, where the oxygen content was 6.7. The structure of the high temperature phase was refined as tetragonal (P4/mmm) by Rietveld analysis using X-ray powder diffraction patterns at room temperature. The low temperature phase which showed superconductivity was analysed using an orthorhombic structural model. However, we refined the structure using a micro-twin model, which fitted the observed diffraction patterns much better than the single phase model.
  • 木島 弌倫, 北村 真, 秋本 茂, 植月 徹, 田中 嘉一郎
    1990 年 98 巻 1134 号 p. 182-186
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    SiC powder compacts were sintered in inductively coupled plasma (ICP) at 4MHz. Boron and carbon were added to SiC powder as sintering aids in the present experiments. The plasma used here was low temperature Ar plasma working at low gaseous pressure=0.2-6.5kPa, since it was easy for samples to be inserted into plasma. Parameters influencing the densification were gaseous pressure, gas flow rate, sintering duration and r.f. out-put power. SiC was found to be extensively densified under the experimental conditions: gaseous pressure=1.0kPa, gas flow rate=70-270 SCCM, r.f. power=12kW, duration=2min. The weight loss during sintering was a problem to be solved in the present low temperature plasma. Morphological studies showed that abnormal grain growth could not be observed. A crystallographic change was observed from 15R and 3C to 6H after plasma sintering.
  • 池田 進, 藤田 寛治
    1990 年 98 巻 1134 号 p. 187-192
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    Effect of substrate temperature on optical and electrical properties of tin oxide thin films prepared by plasma CVD using DC magnetron discharge are discussed. A high density plasma (≅4×1011cm-3) improved the quality of the films. By heating the substrate at 170°C, the films has higher optical and electrical characteristics (optical band gap: 3.5eV, conductivity: 4S/cm, carrier concentration: 2×1020cm-3). When the films prepared at 90°C and 200°-500°C, both transmittance and conductivity decreased. These properties changed depending on crystal structure (amorphous, oriented) and an impurity.
  • 木村 邦夫, 大野 鋭二
    1990 年 98 巻 1134 号 p. 193-197
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    The effect of Au addition on crystallization was investigated for TeOx-Au films used for optical recording materials. Crystallization phases precipitated from the films were found to be AuTe2 in low Au content films and AuTe1.7 in high Au content films. The crystallization rate was much faster in the case of crystalline AuTe1.7 than in the case of crystalline AuTe2. The time required for the signal saturation due to the crystallization of the films irradiated by laser (850nm in wavelength, 8mW/um2 in power) was shortened up to 60ms for the films in which AuTe1.7 was precipitated from 30s for the pure TeOx films in which crystalline Te was precipitated. The transformation mechanism from the amorphous to the crystalline state in these films is discussed.
  • 八木 健, 篠崎 和夫, 加藤 誠軌, 澤田 豊, 水谷 惟恭
    1990 年 98 巻 1134 号 p. 198-203
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    Hot-pressed AlN body without additive and sintered AlN body containing 10wt% Y2O3 were joined by hot-pressing under a pressure of 200kg/cm2 at 1800°C for 10min. The joined samples with the step-like concentration gradient of grain boundary phases were annealed at 1900°C for 0, 0.5, 1 and 3hrs in N2 using carbon container. The initial migration of grain boundary phases from sintered to hot-pressed body was caused by their concentration gradient. Grain boundary phases transferred to the surface were decomposed and nitrided. After the concentration gradient disappeared, the surface reaction caused the migration of grain boundary phases. The grain boundary phases reacted with oxygen in the hot-pressed body, resulting in the depletion of oxygen in the hot-pressed body.
  • 芦塚 正博, 中津 雅治, 石田 英一
    1990 年 98 巻 1134 号 p. 204-207
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    Elastic modulus, Vickers hardness, flexural strength and fracture toughness of diopside (D) glass ceramics containing 33, 38, 43 and 48wt% tricalcium phosphate (TCP) were measured. The glass ceramics were prepared by sintering and crystallization of glass powders. Precipitated crystals were diopside, β-TCP and hydroxy apatite when sintered at 1050° and 1100°C, and diopside, β-TCP and α-TCP at 1150°C. Maximum flexural strength of 67 D-33 TCP, 62 D-38 TCP, 57 D-43 TCP and 52 D-48 TCP were 223, 218, 216 and 163 MPa, respectively. Maximum Young's modulus was 122 GPa for 62 D-38 TCP, maximum Vickers hardness was 494kg/mm2 for 57 D-43 TCP, and maximum fracture toughness was 2.15MPa⋅m1/2 for 62 D-38 TCP.
  • 中村 浩, 梅林 正気, 岸 和司
    1990 年 98 巻 1134 号 p. 208-211
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    The Si3N4-SiC composites which is composed of Si3N4 matrix doped with 2wt% Al2O3 and 5wt% Y2O3, and 50wt% SiC powder having a different mean particle sizes, were fabricated by hot-pressing. Their oxidation behavior was investigated and compared with the commercial Si3N4 sintered material. An oxidation test was carried out in an electric furnace at 1300°C for 100 hours. The measurement of bending strength, weight gain, surface roughness and microscopic observation of sintered materials were carried out after oxidation. Weight gain of the Si3N4-SiC composite was lower than that of the commercial Si3N4 sintered material. The crystalline phases of sintered materials after oxidation test were β-Si3N4, α-SiO2, Y2O3⋅2SiO2 and SiC. The bending strength of Si3N4-SiC composites slightly increased the value after oxidation.
  • 高橋 裕, 藤津 悟, 柳田 博明
    1990 年 98 巻 1134 号 p. 212-214
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    Oxygen desorption from ZnO was measured by TPD technique to estimate the increase in the amount of adsorbed oxygen on ZnO by platinum loading. The total amount of adsorbed oxygen increased by platinum loading where excess oxygen adsorbed not only on platinum particles but also on ZnO. The excess adsorption on ZnO was remarkable at 400°C.
  • 保田 英洋, 小山 久, 森 博太郎, 藤田 広志, 野田 正治, 上垣外 修己
    1990 年 98 巻 1134 号 p. 215-219
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    Bilayer films of Au (target atom)/α-SiC (substrate) were irradiated with 2MeV electrons in an ultra-high voltage electron microscope. By irradiation, gold atoms in the upper layer were implanted into the SiC substrate. Changes in the microstructures and bonding state associated with the implantation were studied by ultra-high voltage electron microscopy and scanning Auger valence electron spectroscopy, respectively. The results obtained are as follows; (1) Irradiation with 2MeV electrons first induces a crystalline-to-amorphous transition in α-SiC. (2) Gold atoms which have been knocked-off from the gold layer by the collision with 2MeV electrons are recoil-implanted into the resultant amorphous SiC. (3) The implanted gold makes preferential bonding with silicon having dangling bonds, and new bonding states are formed between them. (4) During continued irradiation, the gold atoms repeat displacement towards the beam direction, which is induced by the collision with electrons and subsequent bonding with silicon atoms having dangling bonds. The repetition results in the deep implantation of gold into the SiC substrate.
  • 真部 高明, 横田 洋, 熊谷 俊弥, 近藤 和吉, 水田 進
    1990 年 98 巻 1134 号 p. 220-224
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    Superconducting Ba2YCu3O7-δ (BYCO) films were prepared on the yttria-stabilized zirconia substrates by the dipping-pyrolysis process using metal laurates as starting materials. Propionic acid and pyridine were selected as solvents based on the screening test on solubility of each of Ba-, Y- and Cu-laurates in 26 organic liquids with various functional groups. A homogeneous solution of mixed laurates (Ba:Y:Cu=2:1:3) was prepared by using a mixture of propionic acid and pyridine. This solution was spin-coated on the YSZ substrates and preheated at 500°C in air to make (BaCO3-Y2O3-CuO) precursor films. After this procedure was repeated 15 times, the precursor films were heat-treated at 925°-970°C in O2 to give 2μm thick BYCO films, which showed superconduction at Tc, zero of 69-84K. Observation with a scanning electron microscope and X-ray diffraction analysis showed dense textures of orthorhombic BYCO grains.
  • 神保 龍太郎, 鈴木 康隆, 高橋 研
    1990 年 98 巻 1134 号 p. 225-230
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    Relationships between the resistivity and the dispersion state of ZrB2, particles and aggregates, in SiC-ZrB2 electroconductive ceramic composites were investigated by means of image analysis and other measurements. The resistivity decreases with increasing number of longer ZrB2 which has larger aspect ratio, length/average width. The aspect ratio of ZrB2 increases as the length and the content of ZrB2 increase, except for large ZrB2 aggregates which are formed due to insufficient mixing of SiC and ZrB2 powders.
  • 佐藤 和明, Serge HAGÈGE, 栗下 裕明, 吉永 日出男
    1990 年 98 巻 1134 号 p. 231-233
    発行日: 1990/02/01
    公開日: 2010/08/06
    ジャーナル フリー
    Transmission Electron Microscopy (TEM) observations were made on the interface joining a single crystal and a sintered polycrystal of α-SiC. It is shown, that the dihedral angles between boundaries are almost the same at triple junctions where a grain boundary in the polycrystal meets the joined interface and that along the interface there is an amorphous-like layer of approximately 7nm in thickness.
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