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, 1142 号
選択された号の論文の20件中1~20を表示しています
  • 大司 達樹, 山内 幸彦, 兼松 渉, 伊藤 正治
    1990 年 98 巻 1142 号 p. 1063-1069
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    The cyclic fatigue tests at high temperatures were conducted for hot-pressed silicon nitride and sintered silicon carbide, and the results were analyzed by the power-law and exponential crack growth relations. The cyclic fatigue data for both materials were fitted with straight lines in both of log-log and semi-log forms which were based on the former and latter relations, respectively. However, the experimental lifetimes of silicon nitride were substantially longer than those predicted from the results of static fatigue test using either crack growth relation, and this difference was expanded with lowering the applied stress. On the other hand, the experimental and predicted lifetimes relatively well agreed for both of the crack growth relations in silicon carbide. The sensitivity of cavitation expansion behavior to displacement rate was proposed as a cause for the longer life time of cyclic fatigue in silicon nitride.
  • 林 國郎, 奥野 倫大, 岡本 泰則, 西川 友三
    1990 年 98 巻 1142 号 p. 1070-1075
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    The ceramics obtained by sintering glass powders with various chemical compositions have been used for substrates in multilayer packaging, In previous study in MgO-Al2O3-SiO2 system, it was found that the sinterability of glass powders much differed depending on the compositions. To ascertain the origin of this difference in sintering behavior, the viscosity of glasses at sintering temperatures and isothermal shrinkage curves were measured. Temperatures at which crystals precipitated in glasses and activation energies for crystallization were determined with differential thermal analysis. Compacted glass powders sintered by a viscous flow mechanism at temperature range from 830° to 860°C at which the viscosity of glasses decreased as low as about 109 poise. No densely sintered body was obtained by heating a compacted glass powder with the cordierite composition, because cordierite crystals have precipitated during the initial stage of sintering due to its low activation energy. A compacted glass powder containing a fairly large amount of MgO, and low amounts of Al2O3 and SiO2 comparing with the cordierite composition sintered densely, due to the cordierite crystals precipitated in the glasses after the densification have been completed in consequence of increasing stability of the glass. A compacted glass powder with a high SiO2 content did not sinter, In this compact, cristobalite crystals precipitated at grain boundaries (necks of glass grains) in the initial stage of sintering and prevented the densification of the compacts by a viscous flow mechanism.
  • 土谷 敏雄, 山川 宏
    1990 年 98 巻 1142 号 p. 1076-1081
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    Cuprous ion-conducting glasses were prepared in the system CuCl-CuI-P2O5. These glasses had high ionic conductivities of 10-4 to 10-3Scm-1 at room temperature. The conductivities of these glasses increased with increasing Cul content. The ratio Cur+/(Cu++Cu2+) and the mobility of cuprous ion were measured to clarify the relation between Cul content and ionic conductivity. Both the ratio Cu+/(Cu++Cu2+) and the mobility of cuprous ions in these glasses increased with increasing Cul content. The conductivities of these glasses depended on both concentration and mobility of cuprous ions. Therefore, the conduction mechanism in these glasses was considered to be the diffusion path model. Glass transition temperature decreased with increasing CuI content. Infrared spectra and laser Raman spectra were measured to study structure of these glasses. The results showed that Cu+, Cu2+, Cl-, and I- ions are not involved glass network but existed as simple ions in these glasses and these glasses shows open structure with increasing CuI content.
  • 田代 新二郎, 五十嵐 秀二
    1990 年 98 巻 1142 号 p. 1082-1087
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    A lead-based relaxor material for multilayer ceramic capacitors was ground by ball-milling with partially stabilized zirconia balls of 1, 3 and 15mm in diameter and the effects of ball size and particle size of powder on milling rate were studied. Particle size distribution and specific surface area of powders were examined as a function of grinding time. Small zirconia balls in ball milling were effective to grind the powder to submicronmeter. In order to explain these experimental results on the milling rate, an equation for expressing the milling rate was proposed. The new equation is characterized by two parameters, ball size and particle size of the powder. The calculated and observed milling rates agreed well, and the effects of ball size and particle size on the milling rate were quantitatively confirmed It was found by estimating the proposed equation that milling rate of a powder had a maximum value at a ball size. Tha ball size which showed the maximum milling rate increased as particle size and mechanical strength of the powder increased.
  • 武部 博倫, 森永 健次
    1990 年 98 巻 1142 号 p. 1088-1092
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    The process of fabricating yttria-stabilized zirconia (YSZ) tubes consisted of dense and porous layers for solid oxide fuel cell by the slip casting has been discussed. Two types of YSZ powders having different agglomerate particle sizes were used. The size of dispersed YSZ particles was controlled by changing the milling time of YSZ slips, YSZ green bodies consisted of two layers were formed by the slip casting. During the drying process in an ambient atmosphere, no delamination of layers developed for similar permeabilites of dense and porous layers, The sintered YSZ material having dense and porous layers with ralative densities of 96 and 70%, respectively, was obtained by firing at 1300°C for 100min. Because of a similarity of the densification rates of each layer in the early stage of sintering, cracks or defects were not observed in the sintered body, A YSZ tube consisted of dense and porous layers for SOFC was fabricated. The dense layer of electrolyte was 50μm.
  • 森本 繁樹
    1990 年 98 巻 1142 号 p. 1093-1096
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    The phase separation of SiO2-B2O3-Al2O3-ZrO2-RO-R2O glasses and the composition of resulting porous glasses were compared with those of conventional Vycor type porous glasses, Phase separation progressed by the nucleation growth mechanism, pore diameter increased with 1/3 power of time. The rate of phase separation in a ZrO2 containing glasses was smaller than that of Vycor type by factors of 1/10-1/100. The rate determining step was considered to be the viscous flow of network structural units. Amounts of Al2O3 and ZrO2 remaining in the SiO2 skeleton increased with increasing temperature and time. The composition of Vycor type porous glasses remained almost constant regardless of the heating conditions.
  • 横山 豊和, 近藤 光, 内藤 牧男, 吉川 雅浩, 神谷 秀博, 神保 元二
    1990 年 98 巻 1142 号 p. 1097-1102
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    The present work describes the effect of mechanical milling with a vibration ball mill before and after the calcining on the superconductivity, The experimental results showed that the first-step milling before calcining had a greater effect on the critical temperature of the final sintered pellet than the second-step milling after it. Moreover, it was shown that there was a proper range of the first-step milling time to obtain high superconductivity, i.e., too long first-milling caused the reduction of the critical temperature of the sintered product. The same tendency was confirmed by the measurement of susceptibility of the calcined powder. The reason for the degradation of superconductivity by the prolonged milling was ascribed to the inhomogeneity caused by the strong agglomeration of the component particles which was confirmed by the size analysis, observation with a scanning electron microscope and measurement of bulk density of the milled powder. Furthermore, the X-ray diffraction analysis showed that the peak intensity of the superconducting phase of the milled powder decreased gradually with the time of second-step milling after the calcining, though the second-step milling time did not affect the critical temperature of the final product within the range of milling time in the present work.
  • 安田 公一, 金 相東, 金道 幸宏, 松尾 陽太郎, 木村 脩七
    1990 年 98 巻 1142 号 p. 1103-1108
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    The purpose of this paper is to investigate the influence of grain size and temperature on fracture toughness of MgO sintered bodies, Specimens were made by hot pressing, and a wide range of grain size (12-230μm) was obtained by annealing at high temperatures. Porosities of specimens were less than 1%. Fracture toughness of MgO sintered bodies with different grain size, was measured by the Chevron-Notched Beam method at room temperature, 1000° and 1200°C. KIC did not depend on grain size at room temperature, and took the constant value of 1.8MPa√m over a wide range of grain size. On the other hand, KC increased with decreasing grain size at 1000° and 1200°C. This increase in KC at small grain size corresponded to the macroscopic ability of plastic deformation in bending test. Equivalent crack size at room temperature was calculated. Equivalent crack size slightly increased with increasing grain size, and subsequently saturated. This tendency suggested that grain boundaries controlled the growth of microcrack at small grain size.
  • ZrSiO4組成の前駆体ゲルの調製条件
    小林 秀彦, 寺崎 敏広, 森 利之, 山村 博, 三田村 孝
    1990 年 98 巻 1142 号 p. 1109-1113
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    ZrSiO4 powders were prepared from partially hydrolyzed solutions of Si(OC2H5)4(TEOS) and ZrOCl2 aqueous solutions by the sol-gel processing, and the influence of amount of water for partial hydrolysis of TEOS, pH of the ZrOCl2 aqueous solution and mixing time on the formation rate of ZrSiO4 was investigated. The preparation conditions were evaluated by the formation rate of ZrSiO4 after 1.5wt% ZrSiO4 seed crystals were added to the precursor powders and then the powder mixtures were heated at 1200° to 1500°C for 2h. In the preparation of ZrSiO4 composition precursor gels from TEOS-ZrO2 sol and SiO2 sol-ZrOCl2, the H2O/TEOS molar ratio of about 2 and the pH of the ZrOCl2 aqueous solution of about 3 were appropriate. About 2h were necessary for mixing of partially hydrolyzed solution of TEOS and ZrOCl2 aqueous solution to improve the homogeneity of precursor sols, and more than 10h was required for the mechanical mixing of precursor sols. The formation of ZrSiO4 produced by firing the precursor sols obtained from the partially hydrolyzed solution of TEOS and ZrOCl2 aqueous solution at 1300° to 1400°C showed an accelerative increase through the Hedvall effect by silica.
  • 勝木 宏昭, 平田 好洋
    1990 年 98 巻 1142 号 p. 1114-1119
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    A new alumina substrate coated with porous mullite layer consisting of needle-like crystals was developed for improving the physicochemical properties of the substrate surface. Calcined porous alumina substrates with a 40% porosity and an average pore diameter of 0.1μm were dipped into aqueous suspensions of New Zealand kaolin with particle sizes of below 1μm for 5-20sec to form a kaolin layer 10-40μm thick. The porous alumina substrates coated with kaolin were fired at 1500° to 1650°C to enhance the growth of thick needle-like mullite crystals with lengths of 1-10μm and diameters of about 1μm over the surface of dense alumina substrates. The glassy phase coexisting with mullite crystals over the substrate surface was dissolved in a hydrofluoric acid solution. Pillar-like mullite crystals with diameters of about 3μm were formed at the interface between alumina substrate and mullite layer fired at 1650°C. The pillar-like mullite crystals contained a larger amount of Al2O3 than needle-like mullite crystals with the chemical composition of 3Al2O3⋅2SiO2. No cracks were observed at the interface between the alumina substrate and porous mullite layer after thermal shock test with a temperature difference of 400°-450°C.
  • 渡 孝則, 楢木 英二, 鳥飼 紀雄, 松田 應作
    1990 年 98 巻 1142 号 p. 1120-1124
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    Aluminium nitride (AlN) films were prepared by the chemical vapor deposition in the AlCl3⋅NH3-H2 system under an atmospheric pressure. The effects of the synthetic conditions on the deposition rate and the morphology of AlN films were discussed. The deposition rate decreased with increasing distance (X) between the upstream end of the graphite supporting Al2O3 substrates and Al2O3 substrates and with decreasing deposition temperature (Td). The effect of AlCl3⋅H3 concentration (CA) on the deposition rate was very complicated. Generally, the deposition rate increased with increasing CA but decreased between CA=2.5 and 3.4vol%. The morphology of AlN crystals in the films deposited at 800°C depended on the X value; fine (X≅1cm), columnar (X≅2cm), needle-like (X≅3cm), and then whisker-like crystals (X≅4cm). With decreasing Td or increasing CA, the smooth surface AlN films turned rough.
  • 大田 陸夫, 小谷 亘, 福永 二郎
    1990 年 98 巻 1142 号 p. 1125-1131
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    Glasses in the system 2 B2O3-Na2O-Na2F2 were heat-treated at 450° and 500°C in order to locate the position of F ions in the glass. The crystallization rate was measured as a function of Na2O fraction, and precipitated phases were identified by the X-ray diffraction method. From glasses of Na2O rich composition the diborate (2 B2O3⋅Na2O) phase precipitated predominantly, and from NaF rich compositions the B2O3⋅NaF phase precipitated along with NaF crystal. B2O3⋅NaF phase was considered to have the diborate structure and to include F ions attached to 4-fold coordinated boron atoms in the diborate structure. It was implied that some fraction of NaF component is isolated in the glass network. Crystal growth rate became minimum at intermediate compositions. Theoretical analysis has shown that the fusion entropy ΔSf becomes maximum at these compositions and that oxygen atoms and fluorine atoms are randomly distributed in the glass.
  • 直原 和哲, 石原 守
    1990 年 98 巻 1142 号 p. 1132-1138
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    The influence of temperature on the strength and fracture toughness of ZrO2-3mol% Y2O3 (YZ-3), ZrO2-6mol% Y2O3 (YZ-6), ZrO2-12mol% CeO2(CZ-12) and ZrO2-14mol% CeO2 (CZ-14) ceramics was studied from R. T. down to 77K. The strength was estimated by the three-point-bending method and the fracture toughness was evaluated by the size of initial defects observed on the fracture surface. The bending strength of YZ-3 and YZ-6 increased with decreasing temperature, whereas that of CZ-12 and CZ-14 decreased with decreasing temperature. CZ-12 had a tetragonal to monoclinic transformation temperature from R. T. down to 77K. Other ceramics had no transformation temperature. The temperature dependence of strength for YZ-3 and YZ-6 agreed with that of fracture toughness.
  • 大津賀 望, 遠藤 政彦, 上野 晃, 安岡 正喜, 岡出 清
    1990 年 98 巻 1142 号 p. 1139-1145
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    Some characteristics of quartz in pottery stones from various localities and its cristobalitization by firing have been examined by various methods. Specimens were prepared from the pottery stones by crushing, classifying to 10-37μm, and purifying by hot phosphoric acid and fluoric acid. Substitution of Al ion in quartz was confirmed from ESR and EPMA analyses. With the increase in the amount of Al2O3 substitution in quartz, following correlations were observed: (1) increase of unit cell volume, (2) increase of lattice strain, (3) lowering of α-β inversion temperature. Some specimens were found to be mixtures of quartz substituting different amounts of Al2O3. Cristobalitization from quartz in the pottery stones by firing was found to be correlated with the amount of Al2O3 substituted in quartz and a temperature at which quartz convert to cristobalite was lowered with the increase in the amount of substituted Al2O3. Larger amount of cristobalite was formed from the pottery stones with increasing the amount of Al2O3 substituted in quartz and with decreasing the amount of flux components in the pottery stones.
  • 神谷 晶, 中野 喜久男, 奥田 宏
    1990 年 98 巻 1142 号 p. 1146-1152
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    TiC/SiC whisker composites were fabricated by the hot-press method. As a sintering additive, 10wt% Cr7C3 was added and dense sintered bodies were obtained by 1600°C-1h hot-pressing. Mechanical properties of the sintered bodies were influenced by the grain size and the dispersion of the sintering additive. For a grain size of Cr7C3 of 3.53μm, flexural strength (σf) and KIC had maximum values of 660MPa (Vf=10%, hot-pressed at 1600°C for 1h) and 5.2MPa√m(Vf=30%, hot-pressed at 1750°C for 1h), respectively. On the other hand, when hot-pressed at 1900°C for 1.5h without any sintering additive, σf and KIC were 690MPa and 6MPa√m at Vf of 10%, respectively. In the 1900°C-sintered specimens the whiskers and surrounding matrix were ripped off together from the fractured surface, indicating that the crack bowing and deflection have occurred. Such behaviour was not found in the specimens containing a sintering additive, and their whiskers were fractured at the same plane as the matrix fracture surface. This is the reason that 1900°C-1.5h hot-pressed specimens without sintering additive had higher KIC than that with sintering additive. The different fractured surfaces are probably dependent on the residual thermal stress conditions caused by the difference in hot-pressing temperature or by the presence of Cr7C3 in the matrix/whisker interface.
  • 鈴木 勝, 和田 恭典, 山口 喬
    1990 年 98 巻 1142 号 p. 1153-1158
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    The formation, spreading and collision of glass films were observed on 96% alumina substrates for thick film applications. Thin glass frit films on the substrate formed uniform and smooth films upon heating. Thick glass frit films, however, resulted in rough surfaces. The merging behavior of glass films on collision was studied with glasses of the same and different compositions. In the merging area of glass films with the same composition, the glass films did not coalesce leaving a clear boundary. The boundary was more distinct for thinner films but disappeared with increasing thickness. Films with different compositions did not coalesce regardless of the film thickness. Similar spreading experiments on the substrates glazed with the different composition showed that the interfacial interaction plays an important role.
  • 玉利 信幸, 小林 博之, 田中 隆裕, 近藤 功, 小瀬 三郎
    1990 年 98 巻 1142 号 p. 1159-1163
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    Composite ceramics of B4C containing up to 30vol% SiC whisker were fabricated by hot pressing at 2000°-2200°C under 30MPa for 30min. The mechanical properties (bending strength, fracture toughness, hardness, elastic modules) of the hot pressed bodies were measured. Fully dense B4C-SiC whisker composite ceramics were obtained at the whisker contents up to 30vol% at a sintering temperature above 2100°C. These composites had maximum strength at the whisker content of 10 or 20vol% depending upon the hot pressing temperature. The composite containing 10vol% SiC whisker, fired at 2100°C, had the highest strength (about 830MPa), which was 40% larger than that of monolithic B4C. Slight increase of fracture toughness were obtained in the composites because there was no pull-out of whiskers and no crack deflection in the fracture process. The strength and fracture toughness of the composites containing whiskers with a small diameter were lower than those of the composites with a large diameter, since the whiskers with a small diameter could not maintain their original morphology after sintering. The hardness and elastic modulus were 30GPa and 430GPa, respectively, independent of whisker addition.
  • 中村 雅彦, 毛谷 浩一
    1990 年 98 巻 1142 号 p. 1164-1168
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    A hydrophobic surface layer of sub-millimeter was obtained by low temperature DC plasma treatment of a porous building material (ALC) for a few minutes in a CHF3 atmosphere. The present modified surface layer of ALC showed, (a) the repellency against water droprets for a 20-40 minutes and (b) the reduction in water vapor adsorption quite less than a nonmodified sample.
  • 藤木 良規, 渡辺 遵, 小野田 義人, 吉門 進三, 大鉢 忠
    1990 年 98 巻 1142 号 p. 1169-1171
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    Whiskers of A1-xTi2+xM5-xO12(A=Na, K and M=Al, Ga) were grown by the flux method. Na1-xTi2+xAl5-xO12 whiskers were obtained by slow-cooling from a melt at 1300°C using a mixture of 30mol% of a crystal composition of (Na2O)1 (TiO2)1(Al2O3)1 and 70mol% of a flux composition of (Na2O)1(MoO3)1.5. K1-xTi2+xGa5-xO12 whiskers were also obtained in the same growth technique using a mixture consisting of 30-40mol% of a crystal composition of (K2O)1(TiO2)1(Ga2O3)1 and of 60-70mol% of a flux composition of (K2O)1(MoO3)1.5. The x value in general formula was 0.2 from chemical analysis. The A ions are mobile by the existence of vacancy site. These whiskers showed very high ionic conductivities of 2.0-3.0S⋅cm-1 at300K and 32.5GHz.
  • 松下 純一, 長島 秀夫, 斎藤 肇
    1990 年 98 巻 1142 号 p. 1172-1175
    発行日: 1990/10/01
    公開日: 2010/08/06
    ジャーナル フリー
    The oxidation of TiB2 added with Cr and C prepared by pressureless sintering at 1900°C was investigated TiB2 containing Cr and C was heated at 800°C to 1100°C for 36h in air, and weight change was measured to estimate the oxidation resistance. The TiB2 showed a good oxidation resistance at 800°C because of the surface film of TiO2 (rutile) and B2O3 formed by oxidation, which formed a barrier as an oxidation resistant layer. The weight gain of a TiB2 specimen at 800°C for 36h in air was about 1.8mg/cm2, that of the Cr and C containing specimen was about 27mg/cm2 at 1100°C for 36h.
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