著者

武部 博倫 亀田 常治 小松 通泰 米屋 勝利 森永 健次

出版者

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.97, no.1122, pp.166-173, 1989-02-01 (Released:2010-08-06)

参考文献数

11

被引用文献数

9 15

---

The single-phase region of AlON, a spinel type solid solution in the system Al2O3-AlN, has been determined. AlON was synthesized from solid phase reactions between Al2O3 and AlN powder in several reaction vessels. The reaction vessel of porous Al2O3 with AlN coating was suitable for obtaining pure AlON. The single-phase region of AlON was from 28 to 32mol% AlN at 1700°C and from 20 to 34mol% AlN at 1800°C. The lattice parameters of AlON increased from 7.926 to 7.946Å with increasing AlN content. Y2O3-powder was used as a sintering aid to obtain translucent AlON from synthesized AlON powder at low temperature. For 1wt% Y2O3 addition, the translucent AlON was obtained at 1800°C, and its relative density and flexural strength were 99% and 250MPa, respectively.

著者

中平 敦 武田 真一 塩見 治久 大西 宏司

出版者

The Ceramic Society of Japan

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.107, no.1247, pp.662-667, 1999-07-01 (Released:2010-08-06)

参考文献数

29

---

Effect of alcohol solvent in mixing process on the microstructure and sintering behavior of ceramic-based composites was investigated in detail. The mixture of fine ceramic powders was prepared through the conventional ball-milling method with various alcohol media. The particle distributions of fine ceramic powders were strongly dependent on the kind of alcohol employed during ball-milling. Ceramic-based composites were fabricated by hot-pressing the mixture of fine ceramic powders. Their microstructures and some mechanical properties of the ceramic-based composites were evaluated. It was found that the viscosity of alcohol, surface tension and contact angle greatly affect the sinterability and some of the mechanical properties of ceramic-based composites.

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

---

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

北澤 宏一

出版者

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.108, no.1259, pp.S61-S74, 2000-07-01 (Released:2010-08-06)

---

The 1950's and 60's were the decades when the field of traditional ceramics was brought under the light of analytical physical science. Especially sintering process of ceramics, which had been a matter of extreme complexity, was basically understood in terms of the atomistic diffusion process occurring in the bulk and/or on the interface of the coagulated body of the powder. On the extension a high temperature mechanical property, creep, was understood on a similar basis. The knowledge developed led to the discovery of highly dense sintered ceramics, now widely known as translucent ceramics.The author started his career as a ceramist in late 60th when the understanding of sintering kinetics needed further elaboration. One of the apparent contradiction at the time was the fact that the faster diffusing species, i.e., cation in oxides was the rate determining one in the sintering process. There should be some process that enhances the diffusion process of oxygen. Gradually the importance of surface and grain boundary diffusion was paid attention. This review was written by the author in order to summarize many papers, appearing in those days and to establish the systematic view on those studies. He described how various processes involve the ionic diffusion and how grain boundary diffusion affects the processes based on the concept of the ambipolar diffusion. Starting from the accumulated knowledge in the metal and alkali halides as the simple model for ceramic materials, he related the scattered knowledge into a consolidated view that could be applied to ceramics.In relation to this review he wrote additional reviews on “Diffusion Coefficient of Point Defects in Oxides” Yogyo-Kyokai-Shi, Vol. 87, No. 3, 36-42 (1979), and on “Kinetics of Various Mass Transport Processes on the Solid Surfaces, ” Oyo-Butsuri, Vol. 49, No. 6, 579-585 (1980) which in combination still form the basis of the current understanding of the field.

著者

佐多 敏之

出版者

The Ceramic Society of Japan

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.107, no.1242, pp.166-173, 1999-02-01 (Released:2010-08-06)

参考文献数

39

被引用文献数

4 3

---

NaCl powder specimens composed of equally sized (approximately 1.8μm), cubic single crystals were prepared by additions of acetone to saturated NaCl solution at -21°C under various preparation conditions. Grain growth during storage of the powder specimens was found to be greatly influenced by moisture in the ambient atmosphere. Storage of the specimens in a furnace at 400°C prevented grain growth. Compacts of the powder specimens produced by cold pressing (CP) and cold isostatic pressing (CIP) were sintered, or the powders were directly hot-pressed (HP). Relative densities (RD) of the resulting sintered bodies depended on the compaction or sintering conditions. From these sintered bodies, appropriate equations relating bending strength with porosity and grain size were obtained. The high-temperature bending strength increased up to 300°C and then decreased at higher temperatures. Deflections observed in the bending tests incerased with sintering temperature, that is, with the increase in grain size. Observed tensile strength values (5-10MPa) were smaller than observed bending strength values (8-20MPa). Measured values of the Weibull coefficient and fracture toughness were m=5.34 and K1C=1.05MPa·m1/2, respectively. Single crystal specimens obtained from melts by the Czochralski method were also subjected to bending tests. These specimens showed large deflections above 200°C, and strain-hardening phenomena were also observed. Tension tests for single crystal whiskers prepared by condensation of vaporized NaCl in a flowing air conducted along the [100] direction, and showed that the strength incresed with the whisker cross sectional area up to a maximum value and then decreased. The highest stregth value was obtained in vacuum with lower values being obtained in dry air and moist air because of the effects of oxygen and moisture, respectively.

著者

鮫島 宗一郎 河南 学 平田 好洋

出版者

The Ceramic Society of Japan

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.110, no.1283, pp.597-600, 2002-07-01 (Released:2010-08-06)

参考文献数

20

被引用文献数

38 51

---

The thermal expansion of CeO2 and rare-earth-doped ceria (Ce0.8R0.2O1.9, R: Yb, Y, Gd, Sm, Nd and La) was measured in the temperature range from 298 to 1473 K. The coefficients of thermal expansion (CTE) were determined by differentiating the thermal expansion expressed by a polynominal equation of temperature with respect to temperature. The CTE (α1) for Ce0.8R0.2O1.9 was in the range from 10×10-6 to 14×10-6K-1 and increased nonlinearly with increasing temperature. This result was explained by the asymmetric curve of potential energy based on the lattice energy theory. The kinds of dopant gave small effect on the α1 of rare-earth-doped ceria. On the other hand, the average CTE for CeO2 and rare-earth-doped ceria (12.0-12.5×10-6K-1), determined from a linear approximation of thermal expansion with respect to temperature at 298-1273 K, was lower than the α1 and close to the previously reported values.

著者

水野 正雄 山田 豊章

出版者

The Ceramic Society of Japan

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.97, no.1131, pp.1334-1338, 1989-11-01 (Released:2010-08-06)

参考文献数

11

被引用文献数

1 3

---

In the phase diagram study on the system Ga2O3-Sm2O3, the liquidus and eutectic temperatures were measured from the cooling curves of specimens by the specular reflection method with a heliostat type solar furnace. Quenched specimens from the melt were examined by X-ray diffractometry and chemical analysis. In the system, four compounds were found; garnet-type 3Sm2O3⋅5Ga2O3, perovskite-type SmGaO3, monoclinic 2Sm2O3⋅Ga2O3 and orthorhombic 3Sm2O3⋅Ga2O3. These compounds, showed no phase transition during repeated heating and cooling cycles. The compound 3Sm2O3⋅Ga2O3 was found to melt incongruently at 1755±20°C. The lattice parameter were determined to be a0=12.431Å for 3Sm2O3⋅5Ga2O3, a0=7.658Å, b0=10.856Å, c0=11.560Å, β=109.240 for 2Sm2O3⋅Ga2O3 and a0=11.400Å, b0=5.515Å, c0=9.070Å for 3Sm2O3⋅Ga2O3. The solidification points of 3Sm2O3⋅5Ga2O3 and 2Sm2O3⋅Ga2O3 were determined as 1680±20°C, and 1708±20°C, respectively. The phase diagram shows three eutectic points at 1555°C, 1640°C, and 1690°C with 22.5, 55, and 70mol% Sm2O3 composition, respectively. A high temperature phase diagram for Ga2O3-Sm2O3 system was proposed.

著者

武田 真一 中田 慎二 田里 伊佐雄

出版者

The Ceramic Society of Japan

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.99, no.1146, pp.141-145, 1991-02-01 (Released:2010-08-06)

参考文献数

31

被引用文献数

1 1

---

Post-indentation slow crack growth in soda-lime-silica glass in various aqueous RNO3 (R+; Li+, Na+, K+, Rb+) solutions was investigated in order to understand the mechanism of stress corrosion of glass. The crack growth was found to depend on both the concentration and the nature of the supporting electrolytes. The crack growth was enhanced by the change in the concentration of alkali metal ions from 10-4-1M, and also by the nature of alkali metal ions in the order of Hofmeister series Li+<Na+<K+<Rb+ at the ion concentration of 10-2M. These behaviors showed that the results obtained can be interpreted in terms of the molecular structure of the glass/electrolyte interface based on the charged states.

著者

浅岡 裕史 小川 りえ 林 秀考 岸本 昭

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.114, no.1332, pp.719-721, 2006

被引用文献数

8

---

Na&beta;-alumina is a two-dimensional ionic conductor in which insulating spinel layers separate conducting planes of Na⁺ ions. Na&beta;-alumina ceramics is expected to be used as solid electrolytes because it is strong ionic conductor and mechanically reliable. Therefore, we prepared <i>c</i>-plane-oriented Na&beta;-alumina ceramics from three aluminum sources using a hot-pressing method and evaluated their ionic conductivity and mechanical strength. In all samples, the ionic conductivity perpendicular to the pressing direction was ten times greater than in the parallel direction. The mechanical strength parallel to the pressing direction was 1.5 times larger than that in the perpendicular direction. The samples made from a mixture of 50 mol% platelike gibbsite and 50 mol% spherical alumina showed the maximum preferential orientation with favorable relative density.<br>

著者

植松 敬三 澤田 和彦 加藤 善二 内田 希 斉藤 勝一

出版者

The Ceramic Society of Japan

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.96, no.1111, pp.299-304, 1988-03-01 (Released:2010-08-06)

参考文献数

16

---

Densification of high-purity zinc sulfide was studied by the normal sintering at 800°-1200°C for 2h and hot-pressing at 700°-1100°C under the pressure of 10-40 MPa for 1 to 4h. Zinc sulfide densified slightly in normal sintering and marked grain growth accompanied by a slight increase in density was found above 1000°C. High density was achieved by the hot-pressing between 800° and 1000°C and under the pressure of 40MPa. The grain size was approximately 1μm, and no significant grain growth was observed below 900°C. Above 1000°C, the grain growth became increasingly significant with increasing temperature. At 1100°C, high density was not attained; phase transformation and abnormal grain growth were responsible.

著者

北條 純一 前田 英明 加藤 昭夫

出版者

The Ceramic Society of Japan

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.96, no.1116, pp.842-846, 1988-08-01 (Released:2010-08-06)

参考文献数

10

被引用文献数

1 1

---

Amorphous silicon nitride powder (particle size: 0.04μm) obtained by the vapor phase reaction of Si(CH3)4-NH3 system was compacted into pellet and heat-treated in N2 to investigate the crystallization behavior. The amorphous powder crystallized to 100% α-Si3N4 by the heat treatment for 1h at 1550°C. The equiaxed crystalline particles having the size of 1-2μm were obtained when powder was compacted, whereas acicular particles were produced when powder was not compacted. When Si3N4 powder was used as powder bed which covered pellet, the crystalline particles grew extensively and the crystallinity increased with a decrease in the packing fraction of particles in pellet. The heat-treated powder with a low crystallinity consisted of fine amorphous particles and coarse crystalline particles. The crystallization seemed to proceed by a vapor phase growth mechanism, in which SiO vapor takes part as silicon carrier between amorphous particles and crystalline ones. When BN powder was used as powder bed, the crystallization and grain growth were retarded, and the crystal phase contained a small amount of β-Si3N4. Crystallization inhibitor, e. g. boron oxide, may have penetrated into pellet from BN powder.

著者

中平 敦 坂本 清子 山口 俊郎 木島 弌倫 岡崎 正之

出版者

The Ceramic Society of Japan

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.107, no.1241, pp.89-91, 1999-01-01 (Released:2010-08-06)

参考文献数

9

被引用文献数

5 7

---

Hydroxyapatite whisker and platelet were synthesised by the hydrolysis of alpha-tricalcium phoshate (α-TCP) in H2O system and etanol/H2O system at 70°C and atmospheric pressure, thus avoiding severe processing condition, such as in hydrothermal synthesis. The hydroxyapatite prepared by this process was analysed by X-ray diffractometry and transmission electron microscopy observation. The effect of ethanol addition into H2O on the hydrolysis of α-TCP to hydroxyapatite was also examined. The hydrolysis rate of α-TCP to hydroxyapatite was inhibited in the ethanol/H2O system. It was found that the morphology and the aspect ratio of hydroxyapatite could be controlled by adding ethanol into H2O during the hydrolysis reaction of α-TCP.

著者

吉村 昌弘 早川 信 宗宮 重行

出版者

The Ceramic Society of Japan

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.97, no.1131, pp.1339-1347, 1989-11-01 (Released:2010-08-06)

参考文献数

42

被引用文献数

3 4

---

The reactions between TiC or TiN powder and H2O have been studied at 200°-650°C under 100MPa. The reaction of TiC with H2O above 400°C for 3h yielded anatase, CH4, CO2 and H2, and above 500°C rutile was formed additionally. TiN powder with an average grain size of 1.4μm reacted with H2O above 290°C to yield anatase, NH3 and H2, while TiN powder of 9μm reacted H2O above 480°C and yielded rutile, NH3 and H2. The oxidation rate calculated from the weight gain was compared with that from various model kinetic equations. In TiC the rate was best described by the Avrami-Erofeev equation (n=1.3), while the core-shrinking model fitted as well. This suggests that the reaction was controlled by the phase boundary reactions. In TiN the Jander-type model was the best, which suggests that the reaction was controlled by the diffusion through the oxide scale. An Arrhenius plot of the rate constants gave an apparent activation energy of 98kJ/mol. The difference of reaction mechanism between TiC and TiN is attributed to the difference in the gaseous species of reaction products.

著者

竹内 敦子 古滝 敏郎 小山 浩司 砂川 和彦 矢口 洋一 松井 良憲 村杉 政一 関 修平 田川 精一 原 和香奈 吉本 護

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.113, no.1319, pp.478-483, 2005 (Released:2005-07-01)

参考文献数

21

被引用文献数

1 1

---

Nano-dots array whose diameter and interval were approximately 200 nm and 750 nm, respectively, were made parallel to the atomic step edges on sapphire wafers by focused ion beam (FIB) system. Upon annealing a bunched multi-steps structure formed at regularintervals and straight because the steps were pinned at the nano-dots. The step heights andterrace widths were approximately 2.0 nm, 700 nm in off-angle 0.15° and 10.0 nm, 350 nm in off-angle 1.0°, respectively.

著者

中根 久志 青木 早苗 野浪 亨 田中 一彦 森 勝伸 幸本 和人 刀根 如人 亀山 哲也

出版者

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.115, no.1338, pp.151-155, 2007

被引用文献数

2

---

An acid resistant fluoroapatite coated titanium dioxide (FAp-TiO_2) was synthesized by adding a fluoride ion (F^-) to hydroxyapatite (HAp), in order to avoid dissolution of the HAp at an acidic atmosphere. In this study, the optimization of synthetic conditions of FAp-TiO_2 was investigated in terms of the amount of the fluorine (F^-) added to the simulated body fluid, the reaction temperature and the time. The addition of F^- to simulated body fluid was performed after coating HAp on the surface of TiO_2 surface. The crystallinity of FAp phase generated on the TiO_2 was strongly affected by changing the reaction conditions. The optimized synthetic conditions of FAp-TiO_2 as photocatalyst were the addition of 0.25mM-0.5mM F^- in the fluid and then the reaction time for 3h at 60℃. The adsorptivity and the photocatalytic activity of the FAp-TiO_2 in the optimum conditions were investigated using the butyric acid and trimethylamine as model solutions. Consequently, the FAp-TiO_2 could obtain higher adsorptivity and photocatalytic activity for trimethylamine, rather than the uncoated TiO_2.

著者

奥野 雅史 迫川 邦俊 光藤 裕之

出版者

The Ceramic Society of Japan

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.98, no.1136, pp.370-376, 1990-04-01 (Released:2010-08-06)

参考文献数

19

被引用文献数

1 1

---

Recently, Ri, Hamano and Nakagawa have experimentally revealed adsorption effect transistor characteristics of ZnO sinters [Yogyo-Kyokai-Shi, 93, 230-36 (1985); Yogyo-Kyokai-Shi, 94, 419-24 (1986)]. These results are computationally simulated for the sinters having the local states of bulk donors, grain boundary interface acceptors, surface acceptors and thermally desorbable surface donors in conformity with Fermi-Dirac's law for electron occupation, Poisson's equation for potential distribution and charge neutrality condition. Each parameter of the local states is concurrently obtained within the reasonable value. The potential barrier at necks with radius larger than the surface Debye length is weirlikely formed because of the interface and so independent of the surface states (open-out necks). The potential barrier at necks with radius smaller than the surface Debye length is formed in the shape of a saddle because of both the surfaces and the interfaces and so depends on the neck radius and the surface states in addition to the interface states. The bulk resistivity of sinters is obtained by the effective medium approximation for random networks in consideration of the neck radius distribution. The clusters bonded by the open-out necks percolate always through the sinters above 85% in the relative density. On the basis of the above, the hysteresis of bulk resistivity and adsorption effect transistor responses to admission of propane gas are analyzed.

著者

手嶋 勝弥 近藤 人資 鈴木 孝臣 大石 修治

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.113, no.1323, pp.733-735, 2005 (Released:2005-11-01)

参考文献数

17

被引用文献数

1 6

---

Large ruby crystals, exhibiting the typical transparent-red color, have been successfully synthesized by the evaporation of molybdenum trioxide flux. The grown crystals were up to 3.1×3.0 mm in size. In the case of 99 mass% of flux evaporation, the crystal sizes were dependent on the mixture (solute+flux) amounts. A sixfold increase in the mixture amount (30 to 180 g) resulted in double or higher increase in the average sizes (1.2×1.0 mm to 2.5×2.2 mm). The basic form of the grown crystals was a hexagonal bipyramid which consists of twelve well-developed {1123} faces. Furthermore, {0001} faces were also observed in large crystals, besides {1123} faces.

著者

加藤 昌宏 鵜沼 英郎 高橋 実

出版者

The Ceramic Society of Japan

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.108, no.1257, pp.478-481, 2000-05-01 (Released:2010-08-06)

参考文献数

14

被引用文献数

9 9

---

In the aim of the understanding of the coloration mechanism in Cr-doped inorganic pink pigments, the valences of Cr dopant in sphene-type (CaTiSiO5-CaSnSiO5), perovskite-type (CaTiO3-CaSnO3) and rutile-type (TiO2-SnO2) matrices were investigated by use of X-ray photoelectron spectroscopy (XPS). The valences of chromium were directly related to the color of the pigments. The valences were dependent on the Ti/Sn ratio in the mother crystals. Results of XPS showed that chromium ions doped in CaSnSiO5 and CaSnO3 matrices existed Cr4+, causing reddish purple color. With substitution of Ti for Sn in these matrices, the fraction of trivalent chromium increased and the color changed from reddish purple through purple red, red brown and finally to brown. A similar valence change of chromium was observed in the rutile-type pigments that changed lilac through brown to ocar colors. Purple red color was achieved in 2mol% Cr-doped sphene- and perovskite-type pigments containing 20mol%Ti.

著者

森山 実 鎌田 喜一郎 小林 義一

出版者

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.99, no.1148, pp.286-291, 1991-04-01 (Released:2010-08-06)

参考文献数

15

被引用文献数

4 9

---

Titanium nitride (TiN) ceramics without additives were fabricated by the hot-pressing (HP), and their mechanical and electrical properties were investigated. Hot-pressing was performed at various sintering parameters such as sintering temperature (1800°-2250°C), sintering time (30-180min), pressing pressure (2-14MPa) and ambient gas (Ar) pressure (vacuum-10atm). Densification was promoted at higher temperature, higher pressing pressure and longer sintering time. The TiN ceramics fabricated by hot-pressing at 2100°C×60min under the pressing pressure of 14MPa in the normal ambient gas pressure showed the representative properties: bulk density; 5050kgm-3 (relative density 92.8%), Vickers microhardness; 8.52GPa, flexural strength; 265MPa, static modulus (Young's modulus); 387GPa, dynamic modulus; 459GPa, and volume resistivity; 0.360μΩ·m. These properties were affected especially by the ambient gas pressure during hot-pressing. The TiN ceramics prepared in vacuum showed 30-40% augmentation, on the average, in hardness, flexural strength, Young's modulus and resistivity, compared with those prepared under normal (1atm) and higher pressures (5, 10atm). TiN ceramics with high mechanical properties were obtained by sintering in vacuum.

著者

銭 端芬 大矢 豊 中川 善兵衛 浜野 健也

出版者

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.103, no.1202, pp.1022-1026, 1995-10-01 (Released:2010-08-06)

参考文献数

20

被引用文献数

3 3

---

Aluminum titanate ceramics were fabricated from compacts of aggregated mixture of alumina and titania. The mixture was prepared by precipitation of aluminum hydroxide from aqueous solution of aluminum nitrate, containing rutile powder. After calcination, the mixture was crushed and classified to fractions' 2-5, 5-10, 10-20, 20-47 and 47-77μm sizes. The SEM observation of compacts of the aggregates revealed that the aggregates were not broken by the compaction. The fired bodies of the compacts consisted of oriented aluminum titanate grains. The sizes of the oriented regions were about 4 times larger than the initial aggregate sizes. The reasons for the formation of the oriented grains were considered as follows: the formation of aluminum titanate has low change in free energy, increases elastic energy, and is endothermic. Because of these reasons, grain boundary energy becomes significant in nucleation of aluminum titanate and, therefore, the nucleation occurs epitaxially to result in the oriented texture. The semi-quantitative estimation of change in energies during formation of aluminum titanate agrees with the argument.