著者

平田 好洋 松下 晋一 中釜 晋 石原 義巳 堀 三郎

出版者

公益社団法人日本セラミックス協会

雑誌

日本セラミックス協会学術論文誌 : Nippon Seramikkusu Kyokai gakujutsu ronbunshi (ISSN:18821022)

巻号頁・発行日

vol.97, no.1129, pp.881-887, 1989-09-01

被引用文献数

5 14

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Dispersion, rheology and consolidation of the colloidal suspension in the alumna powder-silicon nitride whisker system were studied to control the microstructure and density of the green compact. Al_2O_3 particles with au average diameter of 0.15 μm and Si_3N_4 whiskers with an average size of 0.4 μmX3.7μm were electrostatically dispersed in water in the pH range 3 to 10 and consolidated by filtration. Well- dispersed stable suspensions were obtained at low pH. Decreasing the viscosity and at the same time increasing the solid content of the suspension is the hey step in making the green compact with high density and a narrow pore size distribution. Application of isostatic pressing to compacts consolidated by filtration increased green density and shifted the pore size distribution to smaller size. These green compacts by colloidal processing were densities to relative densities of 98.4-99.4% by hot-pressing at 1500℃ at a pressure of 39 MPa in N_2 atmosphere.

著者

内藤 牧男 堀田 禎 早川 修 篠原 伸広 植松 敬三

出版者

公益社団法人日本セラミックス協会

雑誌

日本セラミックス協会学術論文誌 : Nippon Seramikkusu Kyokai gakujutsu ronbunshi (ISSN:18821022)

巻号頁・発行日

vol.106, no.1236, pp.811-814, 1998-08-01

被引用文献数

9 13

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The effect of ball milling conditions on pulverization of the very small amount of large particles in silicon nitride powder was examined. In this paper, the wet sieve analysis and X-ray sedimentation method were used to measure the content of large particles in the ground powder which influence important properties of sintered ceramics such as fracture strength. As a result, it was made clear-that the wet sieve analysis would be a reliable method to measure the content of just a few large particles in the ground powder. By applying this analysis to the ball-mill grinding of silicon nitride powder, it was found that the processing conditions required to grind the large particles were different from those to obtain high specific surface area as well as small average size of particles. This is because the impact force exerted onto the particles by the media balls is more effective on grinding large particles.

著者

久保 靖 山口 悟郎 笠原 晃明

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.75, no.862, pp.183-192, 1967-06-01

被引用文献数

1

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In relation to three hydrated phases which were obtained by the reactions between the water vapor and the solid phases of nepheline=carnegieite compositions in the foregoing paper, attempts were made to establish a correlation between the structure of the starting solid and the product with a hope that the structure of the starting solid might be inherited to the product. Dehydration experiments of the products were carried out also in relation to clarifying their structural relationships.<br>X-ray powder diffractions of the nepheline hydrate I and the species Y obtained in the previousp aper and of the nepheline hydrate II which is of a low-water type closely relating to these hydrates and obtained by hydrothermal reaction after Barrer's method, were examined and are listed in Table 3-6. All these patterns can be tentatively indexed based on orthorhombic cells which are shown in the tables and also summarized in Table 7. Indexing was made by trial and error based on the available electron diffraction patterns. Some discrepancies, however, are still observed, which may suggest that dehydration occurs to some extent under high vacuum and also by electron bombardment during the electron optical observation.<br>The high temperature X-ray diffraction patterns and thermal analysis curves are illustrated in Fig. 1-8 for the nepheline hydrate I, the species Y, and the hydroxy-sodalite of the present experiments and for a nepheline hydrate II. It seems that in the former three species, some lattice distortion takes place upon partial dehydration as shown by the splitting of the diffraction peaks. The original structure, however, is nearly resumed by further dehydration and eventually goes to a nepheline structure. At the final stage of dehydration double exothermic effects in D. T. A. curves are characteristic for all of these three hydrated phases, which seems to be due to complicated transformation processes including the formation of intermediate sodium aluminosilicate phases. As compared with these, the thermal change of nepheline hydrate II is so simple that dehydration brings about the direct formation of nepheline structure as low as at 600°C. Though little can be said of the actual structures of these phases at present, close relationships between the original solid phase and hydrated product can be demonstrated by a comparison between the lattice parameters as illustrated in Fig. 13 and 15. The lattice dimensions suggest that the structural units of aluminosilicate as illustrated in Fig. 14 are inherited throughout the hydrothermal processes.

著者

久保 靖 山口 悟郎 笠原 晃明

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.75, no.861, pp.140-146, 1967-05-01

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Differing from the previous studies by various investigators, the present research concerns with the formation of hydrated sodium aluminosilicates by the water vapor-solid reactions. Sodium aluminosilicate phases, amorphous or crystalline with nepheline-carnegieite compositions, which were obtained by heating the mixtures, Al₂O₃⋅2SiO₂⋅2H₂O(kaolinite)+<i>a</i>Na₂⋅CO₃(<i>a</i>=1.00-2.00), up to various temperatures below 1300°C, were used as the starting solids. A silver capsule was filled with the starting solid and suspended above the liquid water in a Moley-type autoclave (Fig. 1). The bottom of the capsule was not sealed to allow the water vapor to penetrate into the capsule. The saturated water vapor pressure within the autoclave at 310°C is 100kg/cm². This condition was used throughout the present experiments. Under this condition, the reaction may well be called a hydrothermal metamorphosis.<br>As compared with the previous studies in which the thermodynamic equilibria are attained in the given homogeneous systems, the reactions in the present experiments start at the interfaces between the water vapor and the solid with a consequence that the reaction products are not necessarily equilibrated under the given experimental conditions. As the result, three sorts of hydrated phases, hydroxy-sodalite, nepheline hydrate I, and species Y (a new phase of the composition, Na₂O⋅Al₂O₃⋅2SiO₂ 1.33-1.5 H₂O, which has not been found in the previous hydrothermal studies), were formed during 1-7 days' run according to the nature of the starting solid phases. Correlations among the starting solids and the resulting hydrates are summarized in Table 2 and Fig. 2. In the table the first three columns stand for the preparation of starting solids and the forth the duration of metamorphosis, the fifth the products under the respective experimental conditions.<br>During the hydrothermal treatment, grains of the original solids as shown in the electron microphotographs of Figs. 3 (a)-(c), changed to well-shaped crystallites of the hydrates, nepheline hydrate I and species Y, as shown in Figs. 4(a)-(c), except hydroxysodalite which was formed only in massive grains. Considerable amount of water molecules may have been adsorbed on the surface of solid to gelatinize the surface and eventually to recrystallize the solid into the hydrate crystallites. The original structural framework may still be retained to some extent under these conditions. The metastable phase formation in this experiment will be treated from this point of view in a following paper.

著者

広崎 尚登 井上 靖秀 秋宗 淑雄

出版者

公益社団法人日本セラミックス協会

雑誌

Journal of the Ceramic Society of Japan (日本セラミックス協会学術論文誌) (ISSN:09145400)

巻号頁・発行日

vol.100, no.1161, pp.720-724, 1992

被引用文献数

3 4

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The grain boundary phase in gas-pressure sintered silicon nitride containing 1mol% (SN1) and 10mol% (SN10) of equi-molar Y₂O₃-Nd₂O₃ was investigated using a transmission electron microscopy. In SN1, grain boundary phases were observed in two-grain boundaries and multi-grain boundaries. In SN10, pockets of an additive-rich glassy phase were observed beside two-grain boundaries and multi-grain boundaries, showing that too much additive caused glassy pockets. SN1 contained silica-rich phase in the multi-grain boundary, although SN10 contained additive-rich phase. Silica-rich phase with a lower melting temperature contributed to increased sinterability of SN1.

著者

中村 雅彦

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.86, no.990, 1978-02-01

著者

横田 耕三 村井 俊介 品川 一成

出版者

公益社団法人日本セラミックス協会

雑誌

日本セラミックス協会学術論文誌 : Nippon Seramikkusu Kyokai gakujutsu ronbunshi (ISSN:18821022)

巻号頁・発行日

vol.114, no.1336, pp.1138-1143, 2006-12-01

被引用文献数

2 4

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The influence of particle size distributions of submicron high-purity α-alumina powders on forming and sintering behavior in an agglomerate-free condition were investigated. Nine kinds of alumina powders with the same median diameter (d_<PM50>=0.53μm) and different geometrical standard deviations (σ=1.2-2.0) in lognormal particle size distributions were prepared by blending spherical-like commercial α-alumina powders, and were also adjusted to near ideal distributions so that σ of a mass distribution was comparable with one of the number distribution. In order to prevent the agglomerate and contamination of the impurities, forming was performed by means of the colloid process, i.e., the slip casting method using the porous alumina molds. Relative densities of green compacts and bodies sintered at up to 1300℃ increased with increasing σ, but densities of bodies sintered at 1500℃ or more increased with decreasing σ. The width of the grain size distributions of those bodies increased with increasing σ. The abnormal grains over 30μm of the grain size generated at more than 1.7 of σ for alumina bodies sintered at 1700℃ and those grains contained many pores. The powder with a narrow distribution in size is better to fabricate a translucent material.

著者

藤井 欽二郎 石堂 善彦

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.73, no.832, pp.13-16, 1965-01-01

被引用文献数

1

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高温における純シリカゲルの変化を再検討した. テトラエチルオルソシリケートから調製した微粉状シリカゲル (I) を圧縮成形してつくった円板は, 石英ガラス容器中, 約1150℃の加熱でガラス化して半透体になる. 白金容器中では, このゲルはクリストバライトに変りやすい. 4塩化珪素を加水分解して塊状に乾燥したシリカゲル (II) は, 上記より多少低温, 1050℃で透明になり, 1100℃では, 少量成分おそらく内包された水分を放出してポッピングを起し始める.

著者

Wang Yao-Wen Zhao Peng-Sheng Zhang Yong-Qing

出版者

公益社団法人日本セラミックス協会

雑誌

日本セラミックス協会学術論文誌 : Nippon Seramikkusu Kyokai gakujutsu ronbunshi (ISSN:18821022)

巻号頁・発行日

vol.113, no.1318, pp.409-412, 2005-06-01

被引用文献数

1 2

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A novel joining technique of ceramics to metals is presented, in which depositing Ti on ceramics with arc-added glow discharge is used as a prior metallizing technique and then brazing the ceramics to metals by abnormal glow discharge is carried out. The heating temperature of the base metals is easily controlled by varying the operating voltage and barometric pressure. The ions beam from the glow discharge anode is efficiently able to sputterclean the surfaces of the base materials, which thereby improves better Ti-deposited adhesion on the ceramics and the wetting and spreading properties of the filler metal. The thickness of the Ti-deposited layer is readily adjusted in terms of the actual requirement. The vacuum pressure during brazing can be up to 5Pa. The cost and duration of the glow discharge plasma brazing are reduced as compared with the traditional vacuum brazing process. The joining technique developed holds potential for industrial applications leading to high product quality.

著者

小野 修一郎

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.74, no.850, 1966-06-01

著者

土谷 敏雄 堀内 哲郎 森谷 太郎

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.85, no.979, pp.127-133, 1977-03-01

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Ag₂O-P₂O₅系ガラスは60mol% Ag₂Oまでガラス化出来た. 赤外吸収の比較から, Ag₂O-P₂O₅とNa₂O-P₂O₅は同じ様な構造を持つが, Ag₂O含有ガラスの1280, 1100cm^-1の低波数へのshiftは, Ag-O-Pボンドが共有結合的性格を持つことが示唆された. 電気伝導の結果から, logσはAg₂O量の増大と共に増加し, 熔融温度と時間の増加と共に増加した. Ag₂O-P₂O₅はNa₂O-P₂O₅にくらべ, logσが非常に高く, 低い温度係数を示した. 一方, 誘電測定からのε', ε''は, Ag₂O量の増加と共に急激に増加し, Na₂O-P₂O₅よりも非常に大きな値を示し, 誘電緩和の大きさ<i>Δ</i>εは約50mol% Ag₂Oで極大が観察された. Ag₂O-P₂O₅ガラスの誘電緩和は, 40mol% Ag₂Oより少ない組成ではmigration loss, 50mol% Ag₂O以上の組成ではMaxwell-Wagner lossにもとづく. 銀を含むガラスの特異性は, 他のアルカリイオンの様に, Ag⁺を単なる1価のイオンと見なして電気的性質を理解する事は, 困難である事が示唆された.

著者

大石 修治 望月 圭介 平野 眞一

出版者

公益社団法人日本セラミックス協会

雑誌

日本セラミックス協会学術論文誌 : Nippon Seramikkusu Kyokai gakujutsu ronbunshi (ISSN:18821022)

巻号頁・発行日

vol.102, no.1185, pp.502-504, 1994-05-01

被引用文献数

3 6

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The growih of emerald crystals by the flux evaporation method in the system Mo0_3 B_20_3 rs reported. The crys tal growth was conducted by heating a mixture of a so lute (3BeO・Al_2O_3・6SiO_2+1wt% Cr_2O_3) and a fiux (MoO_3 B_2O_3) at 1100℃, followed by holding at 1100℃ for 10, 20, 25 and 30h. The evaporation loss of flux decreased gradually with increasing amount of B_20_3 ad ded to Mo0_3 and increased with the holding time. The transparent emerald crystals were grown with the typi cal emerald green color in size up to I mm. The crystal size was dependent on the evaporation loss of flux. Hexagonal thin plate like crystals were grown from an Mo0_3 rich flux containing 0.15 0.60 wt% B_20_3. The plate like crystals were bounded by the {0001} and {1010} faces. In rare cases, the small {1120} faces ap peared. Crystals grown froun the MoO_3 flux were twelve sided prism in shape. Molybdenum trioxide con taining a small amount of B_2O_3 was found to be a suita ble flux for growing plate like crystals of emerald.

著者

高良 淳

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.69, no.792, pp.C484-C485, 1961-12-01

被引用文献数

1

著者

野村 勁 藤井 欽二郎

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.77, no.888, pp.271-277, 1969-08-01

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The weight loss in nitrogen atmosphere of compact mixed powders of MgO and carbon at temperatures 1400°-1800°C was followed thermogravimetrically.<br>At any given temperature, the reaction proceeded as a first order reaction (activation energy, 43.8kcal/mole) in an early stage, and zero order reaction followed (53.8kcal/mole). It is considered that the zero order reaction is the characteristic of the reaction of this system, and it will be explained as the effusion of gas evolved in the compact from the surface pores at constant rate (1.3mg⋅cm^-2⋅min^-1 at 1700°C) irrespective of mixing ratio, shaping pressure, or sample weight. The partial pressure of gas in the compact was obtained from the Knudsen effusion equation. For 1700°C, 4.24×10^-6 atm was found, and it corresponds to the vapor pressure of MgO at the same temperature.

著者

新原 皓一

出版者

公益社団法人日本セラミックス協会

雑誌

日本セラミックス協会学術論文誌 : Nippon Seramikkusu Kyokai gakujutsu ronbunshi (ISSN:18821022)

巻号頁・発行日

vol.99, no.1154, pp.974-982, 1991-10-01

被引用文献数

85 1152

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セラミック系のナノ複合材料は粒内ナノ複合材料,粒界ナノ複合材料,ナノ・ナノ複合材料に分類できる.粒内ナノ複合化と粒界ナノ複合化は酸化物及び非酸化物セラミックスの各種の機械的特性を2〜5倍も向上させる.また,高温における硬度,強度,靭性,クリープ・疲労破壊強度,熱衝撃特性もこの手法により著しく改善される.一方,ナノ・ナノ複合材料は金属のような快削性や超塑性変形性などの新機能を発現する.本稿では,まずナノ複合材料の作製法,ナノ構造の観察結果,機械的特性の改善等について報告した後,ナノ分散粒子の役割について考察し,最後にナノ複合材料の将来を展望する.

著者

斎藤 秀俊 砂山 英樹 田中 教雄 大塩 茂夫

出版者

公益社団法人日本セラミックス協会

雑誌

日本セラミックス協会学術論文誌 : Nippon Seramikkusu Kyokai gakujutsu ronbunshi (ISSN:18821022)

巻号頁・発行日

vol.106, no.1239, pp.1051-1055, 1998-11-01

被引用文献数

17 17

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Titanium dioxide films were chemically prepared on (001) single-crystal strontium titanate, SrTiO_3, using a vapor deposition apparatus operating under atmospheric pressure with titanium tetra-isopropoxide. At a substrate temperature of 400℃, titanium dioxide grew epitaxially with lateral growth of steps, as well as multinucleation was observed during the initial growth process, i.e., the so-called Stranski-Krastanov growth. As a result, the surface of strontium titanate was completely covered by titanium dioxide steps with an average lateral growth rate of 100 nm/s, followed by multinucleation growth. The nuclei developed in a number of highly oriented crystallites having well defined facets. X-ray diffractometry and transmission electron microscopy revealed that these crystallites consisted of <001>-oriented anatase-type structure.

著者

宇野 泰章

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.84, no.974, 1976-10-01

著者

中村 雅彦

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.83, no.960, 1975-08-01

著者

中村 雅彦

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.85, no.987, 1977-11-01

著者

浴永 直孝

出版者

公益社団法人日本セラミックス協会

雑誌

日本セラミックス協会学術論文誌 : Nippon Seramikkusu Kyokai gakujutsu ronbunshi (ISSN:18821022)

巻号頁・発行日

vol.100, no.1157, pp.38-41, 1992-01-01

被引用文献数

1

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Thermal Shock tests by arc-discharge heating were carried out on the notched disc specimens of artificial graphite electrodes, while monitoring the change of crack opening displacement (C. O. D.) with time by using a clip gage. The crack abruptly extended from the notch tip at a certain time and stayed at the arc spot in the center of the specimen. The slope θ of the line connecting the origin and C. O. D. just after abrupt extension of the crack, could be determined on each electrode sample within the accuracy of ±10%, independent of notch size. The θ-value thus determined was proposed to be used as a parameter for evaluating the thermal shock resistance of graphite electrode materials and to be named as "thermal shock energy dispersion rate".