Feature: Preparation of Ceramic and Related Materials via Novel Chemical Processing: Review
Feature: Preparation of Ceramic and Related Materials via Novel Chemical Processing: Papers
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Ryohei MAEHANA, Shungo KUWATANI, Koichi KAJIHARA, Kiyoshi KANAMURA
2011 年 119 巻 1390 号 p.
393-396
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Fluorine-doped monolithic silica glasses with low SiOH concentrations were prepared by a sol–gel method using hydrofluoric acid as a fluorine source. Without employing dehydration of dried gels using halogen-containing gases, or vacuum sintering, the concentration of SiOH groups was reduced to ∼10
17 cm
−3 (∼1 ppmw), which is comparable to that of synthetic silica glasses mildly dehydrated during their vapor-phase synthesis. The fluorine concentration evaluated from the intensity of the Raman band of SiF groups (∼945 cm
−1) was in the order of ∼10
20–10
21 cm
−3.
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Tetsuya AYAME, Yoshio KOBAYASHI, Tomohiko NAKAGAWA, Kohsuke GONDA, Mot ...
2011 年 119 巻 1390 号 p.
397-401
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
AgI nanoparticles coated with silica shell (AgI/SiO
2) were prepared with an amine-free process, i.e. a modified Stöber method. A colloid solution of 3.9 × 10
−4 M AgI nanoparticles was prepared mixing silver perchlorate at 3.9 × 10
−4 M and potassium iodide at 7.8 × 10
−4 M. A silica-coating was performed at 4.5 × 10
−6 M 3-mercaptopropyltrimethoxysilane, 0.1 × 10
−3–2.0 × 10
−3 M NaOH, 11–25 M H
2O, and 0.4 × 10
−3–80 × 10
−3 M tetraethylorthosilicate (TEOS) in the presence of 1.0 × 10
−4 M AgI nanoparticles in ethanol. The AgI/SiO
2 particles with a size of 53.2 ± 9.3 nm and an AgI core size of 13.5 ± 4.2 nm were prepared at 1.2 × 10
−3 M NaOH, 15 M H
2O, and 4.0 × 10
−3 M TEOS. The AgI concentration of 1.0 × 10
−4 M in the as-prepared colloid solution was increased up to an AgI concentration of 0.32 M by salting-out and centrifugation. The core–shell structure of AgI/SiO
2 particles was undamaged, and the colloid solution was still colloidally stable, even after the condensation. The concentrated AgI/SiO
2 colloid solution showed a high-contrast X-ray image, and its computed tomography value was 2908 ± 37 HU. Internal organs in a mouse could be imaged injecting the concentrated colloid solution into it.
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Kazuya FUJIMOTO, Takeo OKU, Tsuyoshi AKIYAMA
2011 年 119 巻 1390 号 p.
402-404
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Copper oxide based solar cells with fullerene (C
60) were fabricated on indium tin oxide (ITO) by an electrodeposition method. Cell performance of the solar cells with the Cu
2O/C
60 and CuO/C
60 structures was investigated. A photovoltaic device based on an ITO/Cu
2O/C
60 heterojunction structure provided short-circuit current density of 67 µA cm
−2 and open circuit voltage of 0.20 V under an air mass 1.5 illumination. The microstructures of the Cu
2O and CuO layers were examined, and the energy levels of the present solar cells were also discussed.
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Norihiro SUZUKI, Taimur ATHAR, Yu-Tzu HUANG, Kotaro SHIMASAKI, Nobuyos ...
2011 年 119 巻 1390 号 p.
405-411
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
We synthesize various kinds of mesoporous Nb
2O
5 samples by changing surfactants (P123 and Brij 56), followed by calcination (from 400 to 500 and 600°C). The effect of these parameters helps to produce a well-defined mesoporous framework with crystallinity. The mesoporous Nb
2O
5 samples are well characterized by using small-angle X-ray scattering (SAXS) measurements, N
2 adsorption–desorption isotherms, and wide-angle XRD measurements. In a P123 system, the frameworks are well crystallized to the TT-phase (pseudo-hexagonal) by calcination at 500°C with retention of the mesoporous structures. In the Brij 56 system, after calcination at 500°C, the framework is well retained in an amorphous state. It is proved that the thick walls prepared with P123 are easily crystallized in comparison to thin walls prepared with Brij 56. Furthermore, we investigate the photocatalytic activity by using several types of mesoporous Nb
2O
5 prepared with P123. All these mesoporous Nb
2O
5 samples show photocatalytic activity with their decomposition reaction of methylene blue (MB) molecules. It is concluded that the reaction rates depend on their crystallinities in the frameworks, surface areas, and average mesopore sizes.
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Nobuhiro KUMADA, Jun HINATA, Qiang DONG, Yoshinori YONESAKI, Takahiro ...
2011 年 119 巻 1390 号 p.
412-416
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Single crystals of two types of zirconium phosphates, (NH
4)
2[Zr
2(OH)
2(PO
4)
2(HPO
4)] and (NH
4)Zr
2(PO
4)
3 were prepared under hydrothermal condition using diethylene glycol as a solvent and their crystal structures were determined by using single crystal X-ray diffraction data. The former compound has the layer structure built up by corner-sharing ZrO
6 octahedra and PO
4 tetrahedra, and NH
4+ ions were located in the interlayer space. This compound crystallized in the monoclinic system, space group
C2/
c (#15) and the unit cell parameters were
a = 1.7093(4),
b = 0.8748(2),
c = 0.9216(2) nm and β = 103.69(2)° and the final
R-factors were
R = 0.066 and
Rw = 0.121 for all 5982 reflections. This compound decomposed by releasing NH
4+ ions in the interlayer above 300°C. The later compound has the cubic langbeinite-type structure in which NH
4+ ions were located in the tunnel and the structural refinement by using single crystal X-ray diffraction data was performed for the first time. This compound crystallized in the cubic system, space group
P2
13 (#198) and the unit cell parameters were
a = 1.0198(2) nm and the final
R-factors were
R = 0.072 and
Rw = 0.161 for all 1625 reflections. This compound also decomposed by releasing NH
4+ ions above 800°C.
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Misa SHIMIZU, Akimitsu AOTO, Takuya HASHIMOTO
2011 年 119 巻 1390 号 p.
417-421
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
As a preparation method of proton conducting BaCe
1−xY
xO
3−δ, solid state reaction method and liquid phase mixing one from same raw materials have been compared. By solid state reaction of BaCO
3, CeO
2 and Y
2O
3, segregation of Y
2O
3 was observed in the specimens with
x larger than 0.15. Employing liquid phase mixing method, BaCe
1–xY
xO
3–δ single phase of 0.00 ≤
x ≤ 0.25 with homogeneous Y distribution, has been successfully prepared. It was revealed that crystal system of BaCe
1−xY
xO
3−δ was orthorhombic distorted perovskite and monoclinic distorted one for 0.00 ≤
x ≤ 0.10 and 0.15 ≤
x ≤ 0.25, respectively. The abrupt increase of volume due to the structural phase transition was observed at
x between 0.10 and 0.15.
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Masaki KAKIAGE, Naoki TAHARA, Satomi YANAGIDANI, Ikuo YANASE, Hidehiko ...
2011 年 119 巻 1390 号 p.
422-425
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
The effect of the boron oxide (B
2O
3)/carbon arrangement of the precursor on the low-temperature synthesis of boron carbide (B
4C) powder was investigated in this study. The precursor was prepared by low-temperature heat treatment without thermal decomposition and subsequent pyrolysis in air of the condensed product formed from poly(vinyl alcohol) (PVA) and boric acid. The dispersion state of B
2O
3 particles in the carbon matrix of the precursor significantly affected the acceleration of the synthesis reaction. Crystalline B
4C powder with little free carbon was obtained by heat treatment at 1100°C, which was also the critical formation temperature, for 20 h in an Ar flow starting from a precursor with a B
2O
3/carbon structure homogeneously arranged at the nanometer scale.
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Go KAWAMURA, Yuuki TSURUMI, Hiroyuki MUTO, Mitsuteru INOUE, Atsunori M ...
2011 年 119 巻 1390 号 p.
426-429
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Silver chloride nanoparticle-doped glycidoxypropylsilsesquioxane–titania hybrid films are prepared by the sol–gel method and their hologram-related properties are investigated. The optical absorption of the film embedded with AgCl nanoparticles at a blue laser wavelength is stronger than that of the film embedded with AgBr nanoparticles. The strong absorption of the film with AgCl nanoparticles leads to a considerable increase in absorption in the visible wavelength region upon blue laser irradiation. This phenomenon is generally implicated in good hologram formation ability of the film. A simultaneous addition of AgNO
3 and CCl
3COOH from separate vessels to the sol realizes homogeneous dispersion of AgCl in the hybrid films. The diffraction efficiency of the film exposed to an interferential blue laser shows a good hologram formation ability of the film and a high reliability for readout-angle deviation.
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Naoyuki KITAMURA, Kohei FUKUMI, Kohki TAKAHASHI, Iwao MOGI, Satoshi AW ...
2011 年 119 巻 1390 号 p.
430-433
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Carbon/silica composite films were prepared from colloidal silica aqueous solution in which vapour grown carbon nano-fibers were dispersed. The orientation of nano-fibers was attempted by dip-coating substrates under high magnetic field up to 10 T. The fibers started to align along the direction of magnetic field below 1 T. The degree of orientation was saturated at about 6 T. The anisotropic susceptibility, Δχ = χ
// − χ
⊥, was estimated to be (3.05 ± 1.10) × 10
−7 cm
3/mol from the fitting of numerical simulation. Optical anisotropy, the ratio between transmittances of light polarized perpendicular to and parallel to the direction of fiber orientation, increased immediately in the films prepared under applied fields below 1 T and almost saturated above 1 T. The optical anisotropy was in good agreement with the behaviour of magnetic orientation of fibers.
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Hiromitsu KOZUKA, Takahiro MICHIHATA, Hiroaki UCHIYAMA
2011 年 119 巻 1390 号 p.
434-439
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Silica gel films were prepared on Si(100) substrates from Si(OC
2H
5)
4- and Si(OCH
3)
4-derived sols by dip-coating, and the gel films were heat-treated at 100–700°C. The durability of the films against water was evaluated by measuring the thickness before and after soaking them in 80°C water for 24 h. The durability increased with increasing heat-treatment temperature principally due to the progress of film densification. Higher amounts of water for hydrolyzing Si(OC
2H
5)
4 were greatly effective in achieving higher durability at lower heat-treatment temperatures. Longer sol aging was also effective in improving the durability of the Si(OC
2H
5)
4-derived films. Si(OCH
3)
4-derived films exhibited much higher durability than Si(OC
2H
5)
4-derived ones. All of these factors, i.e. the larger amounts of water for hydrolysis, the longer sol aging time and the employment of Si(OCH
3)
4, may provide more dense film structure and more chance to undergo condensation during gel film heat-treatment, leading to the higher durability at lower heat-treatment temperatures.
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Olim N. RUZIMURADOV, George HASEGAWA, Kazuyoshi KANAMORI, Kazuki NAKAN ...
2011 年 119 巻 1390 号 p.
440-444
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
In this study, we for the first time came up with a facile approach to fabricate hierarchically porous nano-crystalline monolithic magnesium titanates (MgTi
2O
5/MgTiO
3) by impregnating magnesium chloride into hierarchically porous TiO
2 monolith in a solution containing urea followed by appropriate heat-treatment. The formation of porous MgTi
2O
5/MgTiO
3 monolithic materials took place by the solid-state reaction between original TiO
2 networks and precipitated MgCO
3. The MgCO
3 is precipitated within the TiO
2 wet gel by the reaction between impregnated Mg
2+ and CO
2, which is produced by hydrolysis and decarbonation of chelating agent in the TiO
2 wet gels and by the hydrolysis of urea at 60°C. The resultant porous magnesium titanates retained narrow macropore size distribution centered at the diameter ∼1 µm. These porous monoliths produced by impregnation, a facile and the low-cost method, are expected to open various engineering applications owing to the low thermal expansion coefficients and high chemical and physical stabilities.
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Kouichi NAKASHIMA, Midori SAITO, Valery PETRYKIN, Shu YIN, Tsugio SATO ...
2011 年 119 巻 1390 号 p.
445-450
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
A methanol–water mixed solvent was used as a reaction medium for the synthesis of Eu
3+-doped Y
2O
3 (Y
2O
3:Eu) phosphor. Y
2O
3:Eu was prepared under solvothermal conditions at 150–300°C for 3–24 h using a solution of water and methanol as the reaction medium followed by heat treatment at 1000°C for 2 h. The phase composition and optical properties of the products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence spectroscopy. The powders obtained were composed of plate-like particles, spindle-like particles, and whisker particles and were different for samples prepared under supercritical, subcritical, and normal conditions of methanol. With the reaction temperature increasing, the particle size became smaller, in particular, the particles were ∼500 nm in size at 300°C under supercritical condition of methanol. After calcination at 1000°C for 2 h, the obtained powders retained the initial shape. The emission peaks of the fluorescence were assigned to the f–f transitions of the Eu
3+ and exhibited red emission. The fluorescence intensities and internal quantum efficiency exhibited various values dependence on the morphology of the obtained particles.
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Miki INADA, Kazunori IWAMOTO, Naoya ENOMOTO, Junichi HOJO
2011 年 119 巻 1390 号 p.
451-455
発行日: 2011/06/01
公開日: 2011/06/01
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フリー
The preparation of brookite particles was tried by self-hydrolysis of TiOCl
2 with HCl addition. When 0.1 M TiOCl
2 solution was heated at 100°C by reflux method, the precipitate was obtained within 15 min and was identified as brookite and anatase. By addition of HCl, the starting time of precipitation was delayed and small brookite formed beside rutile large rod particles. These results suggest that deprotonation at the early stage of reaction was suppressed but crystal growth at the late stage was promoted because of an increase in the solubility of TiO
2 sols.
When the TiOCl
2 solution was heated at 100°C for 24 h in autoclave, rutile large particles and brookite small particles formed separately. The small brookite particles could be separated by centrifugation. The photocatalytic activity of synthesized brookite particles was lower compared to commercial brookite particles. When hydrothermal treatment was carried out for synthesized brookite, the photocatalytic activity was enhanced. This was due to improvement of crystallinity of brookite.
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Mineo HASHIZUME, Ryota SAITO
2011 年 119 巻 1390 号 p.
456-459
発行日: 2011/06/01
公開日: 2011/06/01
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フリー
Biomimetic mineralization is useful to deposit biominerals on various organic scaffolds under mild conditions. This study investigated the use of molecular self-assemblies as scaffolds for hydroxyapatite (HAp) deposition under body fluid conditions. We also evaluated the scaffold assembly structures during mineralization. A porphyrin derivative having carboxylic acid groups (TCPP) was adsorbed from buffer solutions onto solid substrates to form TCPP self-assemblies. The resulting substrates were then immersed in 1.5SBF, a solution having 1.5 times higher inorganic ion concentrations than those of simulated body fluid (SBF). They were then incubated at 36.5°C. The obtained samples’ surfaces were examined using various physical characterizations such as scanning electron microscopy, FT–IR spectroscopy, and thin-film X-ray diffraction. Furthermore, the samples’ surfaces were monitored spectroscopically during HAp deposition, particularly addressing the Soret band peaks of TCPP assemblies that are sensitive to TCPP assembly structures. Results showed that the TCPP assemblies formed on 2-aminoethanethiol-modified solid substrates induced heterogeneous nucleation and growth HAp on their surfaces while maintaining their J-aggregate structures. No marked effect was observed for TCPP assembly structures during HAp deposition when polyelectrolyte thin films were introduced as a soft layer between the TCPP assemblies and solid substrates, which supported the structural rigidity of the TCPP assemblies against HAp formation thereon.
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Kotaro OZAWA, Naonori SAKAMOTO, Naoki WAKIYA, Hisao SUZUKI
2011 年 119 巻 1390 号 p.
460-463
発行日: 2011/06/01
公開日: 2011/06/01
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フリー
12CaO·7Al
2O
3 (called as C12A7) is composed of [Ca
24Al
28O
64]
4+ cages in which oxide anions are entrapped. Recent studies have revealed that the outstanding characteristics appear by exchanging the free oxide anions in the cages by various other anion species. In the present report, in order to enhance the oxidative catalytic activity of C12A7 by the encaged oxygen radicals, we synthesized C12A7 fine powders with high-specific surface area by sol–gel method and subsequent ball-milling. Aluminum sec-butoxide, calcium nitrate tetrahydrate, absolute ethanol, 1 M hydrochloric acid, and ethyl 3-oxobutanate were used as raw materials. The obtained precursor solution was dried at 100°C for 24 h, and the product obtained was annealed at 900°C in O
2 atmosphere. Planetary ball milling was subsequently applied to the C12A7 powders. The XRD measurements revealed that the synthesized sample was a single phase C12A7. The BET specific surface area of the ground samples was 48.9 m
2/g (24 h ground) and 17.3 m
2/g (36 h ground) for those prepared by sol–gel method and by solid state reaction, respectively. The possibility was thus demonstrated on the synthesis of C12A7 fine powders with higher specific surface area by sol–gel method and subsequent planetary ball-milling.
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Masanori HIRANO, Shingo SATO
2011 年 119 巻 1390 号 p.
464-469
発行日: 2011/06/01
公開日: 2011/06/01
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フリー
The metastable anatase phase of Y
XTi
1−2XNb
XO
2 (
X = 0–0.15) was formed as nanosized-particles from precursor solutions of TiOSO
4, NbCl
5, and YCl
3 under mild hydrothermal conditions using the hydrolysis of urea. The aeschynite phase YTiNbO
6 coexisted with anatase-type titania in the precipitate that was formed at the composition of
X = 0.20. The crystallite sizes of anatase formed under hydrothermal conditions at 240°C for 5 h were approximately 15 nm. The diffuse reflectance spectra continuously varied and optical band gap gradually increased with increased yttrium and niobium content in the samples. The anatase formed at the composition of Y
0.05Ti
0.90Nb
0.05O
2 showed the same level of photocatalytic activity as that of pure TiO
2. The precipitation of YTiNbO
6 phase out of the anatase above 850°C was observed before the formation of rutile through the anatase-to-rutile phase transformation. The crystallite growth of anatase in the course of heating was delayed and the phase transformation shifted into higher temperature more than 150–200°C via the co-presence of yttrium and niobium.
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Takahiro TAKEI, Satoshi INOUE, Qiang DONG, Yoshinori YONESAKI, Nobuhir ...
2011 年 119 巻 1390 号 p.
470-476
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Metal-dispersed porous carbon was prepared from phenolic or furan resin mixed with Co or Ni naphthenate. The formed metal particles in these metal-dispersed porous carbons are apparently smaller than those in the metal-carbon composite prepared from metal nitrate. In the case of the metal-dispersed porous carbon prepared from phenolic resin and Co naphthenate, graphite phase was formed above 800°C around Co nanoparticles. XRD patterns and TEM micrographs confirm that metal naphthenate works as a metal source from which dispersed nanosize metal particles formed. The porous carbons prepared from phenolic or furan resin with Co or Ni naphthenate have specific surface area of approx. 400 m
2/g. For the porous carbon from phenolic resin, mesopore was formed within the sample by cracking or breaking up the large particles. These results indicate that mixing of phenol monomer and the naphthenate before polymerization results in development of mesopore.
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Thomas SCHMALZ, Jan Marcel HAUSHERR, Walter MÜLLER, Tobias KRAUS, ...
2011 年 119 巻 1390 号 p.
477-482
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Porous, polymer derived SiCN ceramics are synthesized from a solid polysilazane (PSZMS) and an ultra-high molecular weight polyethylene (PE) as sacrificial filler. Common analytical methods for the investigation of the thermal decomposition processes and the formed (macro) porosities, such as thermogravimetry and mercury porosimetry respectively, were supplemented by micro computed tomography (µ-CT) measurements. Due to its non-destructive nature, this method enables the comparative analysis of both, the in the first step formed preceramic duromers, to distinguish between the different polymers, as well as the resulting porous ceramics. The via µ-CT determined values for the two polymer phases after cross-linking are in a good agreement with the used original amounts of PE and PSZMS. In contrast the values for the porosity resulting from the PE filler and for the formed SiCN ceramic after pyrolysis differ in greater extent due to the limiting resolution that can be achieved by applying µ-CT measurements.
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Nobuhiro KUMADA, Qiang DONG, Yoshinori YONESAKI, Takahiro TAKEI, Nobuk ...
2011 年 119 巻 1390 号 p.
483-485
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Perovskite-type sodium niobate, NaNbO
3 was prepared by hydrothermal reaction using an amorphous hydrated niobium oxide (a-Nb
2O
5). A single phase of perovskite-type NaNbO
3 was obtained under the condition of 160°C and 1.0 M NaOH solution, and at higher temperature (≥180°C) cubic shape particles with the size of 5–10 µm were produced. These cubic shape particles had well developed 110 and 001 planes. When other starting compounds, Nb
2O
5, HNbO
3·nH
2O and HNb
3O
8·nH
2O were used, well crystallized particles were not obtained. The particles prepared from HNbO
3·nH
2O and HNb
3O
8·nH
2O had irregular shape and cubic-like shape with the size of 1–5 µm. In the case of Nb
2O
5 fine particles with the submicron size of ∼0.5 µm were obtained.
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Yuma MATSUMOTO, Koji TOMITA, Yoshika SEKINE, Masato KAKIHANA
2011 年 119 巻 1390 号 p.
486-489
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
A new solution method that can be used to synthesize borate compounds was developed using citric acid and ethylenediamine. The conventional polymerizable complex method (polyester method) has a significant advantage in terms of homogeneity of the precursor, and it has been utilized in the synthesis of numerous oxide ceramics. However, it is very difficult to synthesize borate compounds by the conventional polymerizable complex method because boron reacts with the glycol that is necessary for the polymerization as polyester and is volatilized from the solution. In this paper, functional borate compounds such as YBO
3:Eu
3+, InBO
3, and K
3Ta
3B
2O
12 were synthesized by the conventional polyester-type polymerizable complex method as well as the new solution method. In the polyester method, citric acid was dissolved in propylene glycol and the component metal salts were then dissolved in this solution. In the method that we propose in this paper, citric acid and ethylenediamine were dissolved in distilled water, and component metal salts were added to the solution. All solutions were heated at 403 K with stirring for the polymerization reaction to proceed, yielding polymer resins. The resins were heated to 723 K and powder precursors were obtained. The precursors were calcinated under various temperature conditions. In the case of YBO
3:Eu
3+, the formed product was Y
2O
3 by the polyester method due to volatilization of boron. On the other hand, single-phase YBO
3:Eu
3+ was synthesized by the new method. YBO
3:Eu
3+ synthesized by the method showed higher photoluminescence intensity than samples synthesized by a solid-state reaction method and the complex gelation method. Synthesis of single phase InBO
3 and K
3Ta
3B
2O
12 was also successfully demonstrated by the method using a very small excess amount of H
3BO
3.
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Ainun Rahmahwati bt AINUDDIN, Norio HAKIRI, Hiroyuki MUTO, Mototsugu S ...
2011 年 119 巻 1390 号 p.
490-493
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Sol–gel derived phenylsilsesquioxane (PhSiO
3/2)–methylsilsesquioxane (MeSiO
3/2) films were prepared on soda-lime-silicate (SLS) glass substrates by dropping and spreading method. The mechanical properties of the pure MeSiO
3/2 and 20PhSiO
3/2·80MeSiO
3/2 (in mol %) films were measured as a function of heat treatment times and temperatures using a nanoindentation test with a Berkovich indenter. The relative residual depth (ξ
r) of films decreased and the film hardness (
HM) significantly increased with increasing heat treatment times and temperatures. The mechanical properties of the films well reflect the changes in the chemical structures and the evolution of siloxane networks with the heat treatment.
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Kazuhiro YAMAMOTO, Satoshi MATSUSHIMA, Koji TOMITA, Yasuyuki MIURA, Ma ...
2011 年 119 巻 1390 号 p.
494-497
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
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We developed a new synthetic route of water-soluble complexes using TiCl
4 and Ti(SO
4)
2 as starting materials. The yield of Ti and the removal rate of the Cl
− ion were over 85 and 98%, respectively. The lactato titanium complex solution obtained by this new synthetic route remained stable for more than 3 months without any precipitation. Single-phase CaTiO
3, SrTiO
3, and BaTiO
3 were synthesized from the lactato titanium complex by heating at 873 K for 5 h. The nano-structured CaTiO
3, SrTiO
3, and BaTiO
3 particle sizes were 50, 30, and 30 nm in diameter, respectively, and smaller than those obtained by the solid-state method. We have succeeded in the synthesis of very fine particles of CaTiO
3, SrTiO
3, and BaTiO
3 at a temperature 400 K lower than that required for the solid-state method.
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Masaomi NAGASAKA, Dai IWASAKI, Naonori SAKAMOTO, Desheng FU, Naoki WAK ...
2011 年 119 巻 1390 号 p.
498-501
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
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0.3 M BaTiO
3 (BT) precursor solution was prepared by the modified CSD, in which partially hydrolyzed Ti-alkoxide and Ba precursor solution was reacted in iced water bath to prepare the highly polymerized BT precursor solution. The BT precursor solution was spin-coated on a Pt/Ti/SiO
2/Si substrate with and without (100)-oriented LaNiO
3 (LNO) thin film electrode. In addition, effect of the pre-annealing at 600°C in O
2 atmosphere was elucidated by measuring the electrical properties of the resulting BT thin films deposited by the different annealing process. The results clearly indicated that the 600°C pre-annealing and the LNO thin film electrode are effective to enhance the electrical properties of the resultant BT thin films from the precursor solution by the partial hydrolysis method.
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Tadao SATO, Yasuhiro SASAKI, Isao SAEKI
2011 年 119 巻 1390 号 p.
502-506
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
The Al
2O
3–TiB
2 sintered compact was synthesized by a reaction, Ti + 2Al + B
2O
3 = Al
2O
3 + TiB
2, during hot isostatic press (HIP) with mixed powders of Ti, Al and B
2O
3 as starting materials. It was found that pre-cooling at −5°C and milling at 0°C suppress the reaction to proceeding mechanochemically, and extend the time for mixing. Scraping off clung powders inside of container during the milling made powders fine and uniform. The longer milling time and uniformity of the powders achieved by the above treatments made it possible to obtain Al
2O
3–40.5 mass % TiB
2 with 99.5% relative density and Hv = 2800.
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Kota SHIBA, Makoto OGAWA
2011 年 119 巻 1390 号 p.
507-512
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Monodispersed spherical particles of zirconium-containing titania-octadecylamine with the size of 300–400 nm and CV value of around 5% were synthesized by a sol–gel reaction in the microreactor. Octadecylamine played a roll as a porogen as well as morphological template of spherical particles. The incorporation of zirconium was confirmed by SEM, TG-DTA, XRD and XRF. The hybrids were converted to nanoporous particles without morphological alteration which had the specific surface area of 300 m
2·g
−1 after removing the porogen (octadecylamine) and that of 60 m
2·g
−1 after subsequent heat treatment at 600°C, while non-porous products formed by calcination at 600°C without washing with hydrochloric acid/ethanol mixture to remove octadecylamine.
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Quang Duc TRUONG, Makoto KOBAYASHI, Hideki KATO, Masato KAKIHANA
2011 年 119 巻 1390 号 p.
513-516
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Phase- and morphology-control of TiO
2 was performed by a facile hydrothermal method using a novel water-soluble titanium–picolinato complex as a precursor. Single-phase rutile or brookite type titania can be obtained by tailoring the pH of the complex solution. Rutile with a hierarchical microstructure was synthesized using an excess amount of ligand as an additive and the final product consisted of microspheres with mesopores formed by a self-assembly of nanorods. The anisotropic growth of nanorods with a high aspect ratio was explained by a capping mechanism.
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Mun Teng SOO, Go KAWAMURA, Hiroyuki MUTO, Kuan Yew CHEONG, Zainovia LO ...
2011 年 119 巻 1390 号 p.
517-521
発行日: 2011/06/01
公開日: 2011/06/01
ジャーナル
フリー
Mesoporous ZrO
2 thin films were fabricated via sol–gel technique by introducing a surfactant, Pluronic P123. The mesoporous structure was tailored by altering several key processing variables including calcination temperature and heating rate. The samples prepared were characterized systematically with X-ray diffraction and electron microscopy. The pore size of the mesoporous ZrO
2 synthesized was ca. 8 nm and the corresponding thin film thickness was ca. 60 nm. It was found that at a relatively high heating rate, the mesoporous ZrO
2 produced had partially-ordered mesoporous structure and its wall structure was semi-crystalline. A mechanism was proposed for this structure formation.
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Feature: Preparation of Ceramic and Related Materials via Novel Chemical Processing: Technical reports
Feature: Preparation of Ceramic and Related Materials via Novel Chemical Processing: Notes