著者

Kazuma OIKAWA Kei TOYOTA Shigeaki SAKATANI Yamato HAYASHI Hirotsugu TAKIZAWA

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 (ISSN:18820743)

巻号頁・発行日

vol.125, no.12, pp.906-912, 2017-12-01 (Released:2017-12-01)

参考文献数

13

被引用文献数

4

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Hydrophobic silica xerogels containing trimethylsilyl (TMS) and dimethylsilyl (DMS) organic hydrophobic functional groups were synthesized using waterglass as the starting material. Five types of hydrophobic silica xerogels with varying surface coverages of the TMS and DMS groups were synthesized by changing the molecular structure of siloxane, which was used to introduce the hydrophobic moieties into the hydrogel and to investigate the resultant surface structures and thermal characteristics. The results revealed that the relative area of silica xerogels was smaller with a higher coverage of DMS groups. In addition, the thermal decomposition temperature of the silyl group shifted to higher temperatures, and the weight reduction during heating was also relatively limited in the above samples.

著者

Katsunori KOSUGE Atsushi YAMAZAKI Atsumu TSUNASHIMA Ryohei OTSUKA

出版者

The Ceramic Society of Japan

雑誌

Journal of the Ceramic Society of Japan (ISSN:09145400)

巻号頁・発行日

vol.100, no.1159, pp.326-331, 1992-03-01 (Released:2010-08-06)

参考文献数

15

被引用文献数

32 59

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In order to synthesize well-crystallized magadiite and kenyaite as a single phase in a short reaction time, amorphous silica was hydrothermally reacted with alkaline solutions in the temperature range from 150°C to 200°C. From a suspension containing SiO2 and NaOH with molar ratios of H2O/SiO2=18.5 and NaOH/SiO2=0.23, magadiite was formed after a reaction time of 48 h at 150°C or after 18h at 170°C. The formation of Na-kenyaite, however, required 6h at 200°C. Then, KOH and K2CO3 were used to lower the formation temperature of kenyaite. K-kenyaite was synthesized after 16h at 185°C from a suspension with molar ratios of H2O/SiO2=18.5 and KOH/SiO2=0.23. Furthermore, (Na, K)-kenyaite was formed after 48h at 150°C or after 24h at 170°C from suspensions with molar ratios of H2O/SiO2=18.5, NaOH/SiO2=0.23 and NaOH/K2CO3=0.95-23. Magadiite and kenyaite were formed through a difinite induction period after dissolution of amorphous silica.

著者

Katsuyoshi OH-ISHI Ryota KOBAYASHI Kengo OKA

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 (ISSN:18820743)

巻号頁・発行日

vol.125, no.5, pp.383-386, 2017-05-01 (Released:2017-05-01)

参考文献数

27

被引用文献数

9

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We estimated site potentials for respective Li ions in the unit cell of Li4SiO4 crystal structure using the VESTA program and examined relation between the estimated site potentials and reactivity of the respective Li ions to CO2. Values of the estimated site potentials for the respective Li ions were distributed over a range of the shallowest level (−11.6 V) to the deepest level (−17.3 V). It is forecasted that the depth of these potentials would relate with reaction between CO2 and the respective Li ions in the unit cell of the Li4SiO4 crystal structure.

著者

Tatsuro HORIUCHI Tsutomu SONODA

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 (ISSN:18820743)

巻号頁・発行日

vol.125, no.3, pp.159-164, 2017-03-01 (Released:2017-03-01)

参考文献数

22

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ZnO:Al thin film was deposited on glass substrates at room temperature. We used a ceramic ZnO:Al target. Since the oxygen vacancies were artificially introduced into the target, thin film could be deposited by DC magnetron sputtering. When ceramic targets are used, fabrication of transparent conductive ZnO:Al thin film in the facing-target is impossible, due to direct resputtering by oxygen anions. The substrate was colored yellow, and the conductivity was also lost. In this state, the thin film was considered to be “ZnO1−x:Al”. In order to avoid the damage, we used a shield consisting of an upper plate, side plates, back plate and base plate. The substrate encapsulated in the assembled shield was placed on the anode in the magnetron sputter we used, the target was installed in the upper side of the chamber and the anode was installed in the under side. We also described the method of deciding the size of the shield. “Thermalized” sputter particles entered the channel consisting of upper plate, side plates and base plate, and are deposited on the substrate. The oxygen anions were blocked by the shield plates. The values of the resultant thin films were enumerated. Carrier concentration was 1.25 × 1021 cm−3, a rather high value. Resistivity was 1.13 × 10−3 Ω cm and Hall mobility was 4.43 cm2/Vs. Also in the area of high temperature superconductive oxides, thin films were damaged by resputtering by oxygen anions. A shield was also tried in this area. In such cases, simple metal plates were installed beneath the substrates in an off-axis position. Side shields were not installed beside the substrates. This confirmed the necessity of side shield plates. We removed the side shield plates and conducted sputtering. The carrier concentration was 6.92 × 1019 cm−3, resistivity was 1.15 × 10−2 Ω cm and Hall mobility was 7.86 cm2/Vs. Based on these values, the effectiveness of the side plates was confirmed.

著者

Mahunnop FAKKAO Kazuki CHIBA Yuta KIMURA Takashi NAKAMURA Toyoki OKUMURA Kiyofumi NITTA Yasuko TERADA Yoshiharu UCHIMOTO Koji AMEZAWA

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 (ISSN:18820743)

巻号頁・発行日

vol.125, no.4, pp.299-302, 2017-04-01 (Released:2017-04-03)

参考文献数

9

被引用文献数

14

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In this work, we directly observed the reaction distribution formed in a composite cathode of the all-solid-state lithium-ion battery (ASSLIB) LiCoO2/Li2.2C0.8B0.2O3|Li2.2C0.8B0.2O3|PEO|Li during charging by using the two-dimensional X-ray absorption spectroscopy (2D-XAS) at Co K-edge. The two-dimensional mapping of the state of charge in a composite cathode indicated that the reaction distribution was formed during charging process in the in-plane direction due to the disconnection in electron pathway at cracks. It was experimentally confirmed that the 2D-XAS technique was a useful tool for evaluating the reaction distribution in a composite cathode of an ASSLIB and investigating the influence factors for the formation of the reaction distribution.

著者

Lv PEILING Yang HANXIAO Camille GAZEAU Kouichi YASUDA

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 (ISSN:18820743)

巻号頁・発行日

vol.121, no.1412, pp.338-343, 2013-04-01 (Released:2013-04-01)

参考文献数

21

被引用文献数

3

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Co-sintering was carried out in air at 1350°C for 1 hr to make two types of symmetrical 3-layered laminates. One is PDP (Porous alumina/Dense alumina/Porous alumina) laminate and another is DPD laminate. For the porous alumina layer, the porosity was set to be 20%; however, pore size was changed by adding three sizes of spherical mono-dispersed polymethyl methacrylate particles (5, 15, 30 µm) in raw alumina powder. Young’s modulus measurements revealed that cracking occurred in both PDP and DPD laminates. The stress in the layer was estimated from an elastic calculation by using the mechanical and thermal expansion properties of each monolayer. In consideration of sintering shrinkage and thermal expansion of the layer, it was suggested that cracking occurred in the dense alumina layer during heating from 1000 to 1200°C, and in porous alumina layer during heating from 1200 to 1350°C. The cracking was mainly attributed to the mismatch of sintering shrinkage between the layers. From the discussion, the elastic model gave an explanation to crack formation during co-sintering.

著者

Haruna SAWAGUCHI Jiale XU Takahiro KAWAI Takashi MINETA Yoshimune NONOMURA

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 (ISSN:18820743)

巻号頁・発行日

vol.124, no.6, pp.753-756, 2016-06-01 (Released:2016-06-01)

参考文献数

16

被引用文献数

4

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Apatite-coated silicon wafers are expected to be utilized for novel biosensors or implants. However, the mechanism and optimum conditions for the formation of an apatite layer on silicon wafer surfaces are unclear. Herein, we examined the effect of pretreating silicon wafers with titanium sputtering and weak alkali aqueous solutions before immersing them in a simulated body fluid (SBF). A week after immersion, silicon wafer surfaces coated with thin titanium layers were covered by hemispherical apatite particles that were produced in a heterogeneous nucleation reaction, whereas untreated silicon wafer surfaces were covered by spherical particles that were produced in a homogeneous reaction. Pretreatment of titanium-coated silicon wafers with 0.1 M NaOH aqueous solution assured heterogeneous apatite formation. Both titanium-coated and untreated silicon wafers were fully covered by the apatite layer after soaking in the SBF for 2–3 weeks. These findings show that pretreatment of silicon wafers with titanium sputtering and weak alkali aqueous solution is effective for obtaining apatite-coated silicon wafers.

著者

Reiichiro TSUCHIYA Takumi TANAKA Gen HAYASE Kazuyoshi KANAMORI Kazuki NAKANISHI

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 (ISSN:18820743)

巻号頁・発行日

vol.123, no.1441, pp.714-718, 2015-09-01 (Released:2015-09-01)

参考文献数

17

被引用文献数

5

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Conventionally, commercialized spherical silicone powders, such as silicone resin powder [INCI: POLYMETHYLSILSESQUIOXANE (PMSQ beads)] and silicone rubber powder [INCI: DIMETHICONE/VINYL DIMETHICONE CROSSPOLYMER (DVDC beads)], have been formulated into cosmetics for soft and smooth feeling. Due to the low crosslink density, silicone rubber powder shows soft touch and high oil absorption. However, it is too agglomerative to be formulated into powder foundation. In this work, we have developed the novel soft touch spherical silicone beads made from methyltrimethoxysilane (MTMS) and dimethyldimethoxysilane (DMDMS), using a surfactant, cetyltrimethylammonium chloride (CTAC). The preparation procedure of the novel silicone beads requires only homogeneous mixing and includes no other complicated operations. The 29Si NMR and TG measurements indicate that DMDMS is randomly incorporated into the methylsiloxane network. The particle size of the beads can be controlled by the concentration of urea as well as by the stirring speed in the sol–gel reaction. By carefully adjusting these parameters, the size of the beads has been optimized for the use in make-up cosmetics. It was revealed by various evaluation measurements that the novel silicone beads exhibit unique characteristics, such as softness, low oil absorption, high transparency and light diffusion effects.

著者

Kohei HOSOI Jong-Eun HONG Takaaki SAKAI Shintaro IDA Tatsumi ISHIHARA

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 (ISSN:18820743)

巻号頁・発行日

vol.123, no.1436, pp.182-186, 2015-04-01 (Released:2015-04-01)

参考文献数

24

被引用文献数

1 4

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Preparation of Microtubular cell using doped lanthanum gallate (LSGM) electrolyte with a dip coating and co-sintering process was studied. In order to suppress Ni diffusion from Ni-based anode substrate to LSGM electrolyte layer, Ti added La-doped ceria (Ti-LDC) was inserted as buffer layer. The amount of Ni diffused in LSGM electrolyte was investigated by EDX analysis as a function of sintering temperatures. It was found that sintering at 1350°C is suitable from the sintering density and the Ni diffusion. The cell sintered at 1350°C exhibited the higher power density than that of the conventional LSGM micro-tubular cell, even though a small amount of Ni diffusion was still observed at the Ti-LDC buffer layer/LSGM electrolyte interface. The micro-tubular cell with around 50 µm thickness showed the open circuit potential higher than 1.0 V and the maximum power density of 0.69, 0.31 and 0.12 W/cm2 at 700, 600 and 500°C, respectively, were achieved.

著者

SUZUKI Yoshikazu MORIMOTO Masafumi

出版者

The Ceramic Society of Japan

雑誌

Journal of the Ceramic Society of Japan (ISSN:18820743)

巻号頁・発行日

vol.118, no.1381, pp.819-822, 2010-09

被引用文献数

21

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Porous ceramics based on refractory double oxides are promising for the next-generation diesel particulate filter (DPF) materials. Similarly to aluminum titanate (Al2TiO5), MgTi2O5 has a pseudobrookite-type crystal structure with low thermal expansion coefficients among oxides. Since MgTi2O5 has higher stability of pseudobrookite phase than Al2TiO5, it is expected that MgTi2O5-based materials are suitable for the next-generation DPF materials. In this study, porous MgTi2O5/MgTiO3 composites have been prepared by in situ processing (viz. reactive sintering) at 1000–1200°C. Porous MgTi2O5/MgTiO3 composites with very narrow pore-size distribution at the diameter of ∼1 µm were obtained by the pyrolytic reactive sintering at 1000–1100°C. Internal pore-structure was characterized by mercury intrusion–extrusion porosimetry.

著者

KOZAWA Takahiro YANAGISAWA Kazumichi SUZUKI Yoshikazu

出版者

Ceramic Society of Japan

雑誌

Journal of the Ceramic Society of Japan (ISSN:18820743)

巻号頁・発行日

vol.121, no.1411, pp.308-312, 2013-03

被引用文献数

13 4

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Solid-state reaction between BaCO3 and ZrO2 is the simplest method to prepare BaZrO3, which is an important refractory structural material with a very high melting point and a low chemical reactivity. However, since the solid-state formation of the BaZrO3 phase requires high calcination temperature, this method typically produces larger particles unsuitable for the sintering process than the solution methods. In this study, we investigated the reaction behavior between very fine ZrO2 (70 nm) and coarse BaCO3 (1.5–5.7 µm) and described the water vapor-assisted solid-state synthesis of BaZrO3. Nanocrystalline BaZrO3 powder (~80 nm) was obtained by solid-state reaction at 1050°C in air. The BaZrO3 formation was accelerated by water vapor-assisted reaction. The apparent activation energy for the formation reaction was calculated to be 323 ± 21 kJ/mol and 263 ± 46 kJ/mol in air and humid air with H2O of 0.5 atm, respectively. In the 1 atm water vapor atmosphere, almost single-phase BaZrO3 was obtained by calcination at 750°C.

著者

Hamid SARRAF Reinhard HERBIG

出版者

The Ceramic Society of Japan

雑誌

Journal of the Ceramic Society of Japan (ISSN:18820743)

巻号頁・発行日

vol.116, no.1357, pp.928-934, 2008 (Released:2008-09-01)

参考文献数

19

被引用文献数

2 5

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This paper describes a convenient and rapid colloidal measuring process of electrokinetic (ζ-potential, ESA signal) properties of the relatively concentrated aqueous suspensions of a submicron α-Al2O3 powder with the anionic polyelectrolyte (Dolapix CE64) dispersant by applying of an advanced electrokinetic sonic amplitude "ESA" technique without dilution. In addition to ESA measurement, the following measurements were also applied: the viscosity, sedimentation, Bingham yield value and prticle size distribution. Very good agreement is observed from the relationship between the electrokinetic (ζ, ESA) values, the viscosity and its pH dependence for each concentrated α-Al2O3 suspension with different amounts of dispersant. The results indicate that the amount of 0.4 mass% Dolapix CE64 is the optimum amount of dispersant that can cause electrosteric effect and decreases mean (d50) particle size of different concentrated (2 vol% and 45.68 vol%) α-Al2O3 suspensions near to the original size. Finally, the study illustrates that Dolapix CE64 is an effective dispersant at all solid loading conditions.