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An investigation has been made on the local structure and the gel to crystalline conversion mechanism in BaTiO₃ gels derived from hydrolysis of concentrated Ba, Ti alkoxide precursor solution with a Ba/Ti molar ratio of 1.00 during aging at 30 degree by means of Ba L_{_III_}-edge EXAFS, Ti K-edge XANES. The results indicate that the spectrum of the BaTiO₃ gels changed by the aging time, and finally, the spectrum of the BaTiO₃ gels aged at 30 degree for 120h is similar to the spectrum of the commercial BaTiO₃ powders.

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The nanocomposite of an epoxy resin and TiO₂ nanoparticles were prepared by dispersing the phenylphosphonic acid (PPA) modified-TiO₂ nanoparticles in the epoxy resin. The FT-IR spectra of the nanocomposites showed the absence of ν(P=O) band at ∼ 1220 cm^-1, suggesting that PPA was interacted with the surface of TiO₂ nanoparticles. The prepared nanocomposites exhibited high transparency up to 15mass% TiO₂.

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Lanthanum-iron mixed oxides with the perovskite structure are widely used as catalysts, sensors, etc. In this study, the synthesis of LaFeO₃ by the solvothermal method was examined, and it was found that this compound was formed by the solvothermal reaction of La acetate (La(OAc)₃) with Fe acetylacetonate in the presence of amine. The yield of LaFeO₃ was analyzed by Rietveld method, which suggested that the phase-pure LaFeO₃ was obtained in the presence of hexamethylendiamine with N/(OAc)=20.

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We succeeded in preparation of new water-soluble titanium complexes with Glycelic acid, 2-Hydroxybutyric acid, Quinic acid, Mandelic acid, Leucic acid or trans-1,2-Cyclohexanediaminetetraacetic acid(CyDTA). These complexes are very stable in neutral water even under basic condition. Hydrothermal treatment of these complexes at 200 degrees Celsius for 24 h resulted in the formation of rutile, anatase, mixture of both or of anatase / brookite type titanium dioxide by varying the ligands.

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We succeeded in synthesis of Rutile-type TiO2 nano-particles and needle-like shaped Anatase-type TiO2. Nano-Rutile samples were prepared by hydrothermal treatment of titanium-tartarate complex in the presence of large amount of hydrogen peroxide. Particle size of the prepared rutile was around 10 nm and BET surface area was 118 m2/g. And needle-like shaped Anatase samples were prepared by hydrothermal treatment of titanium-tartarate complex in the presence of ethylenediamine. Particle size of the prepared Anatase was about 30 by 150 nm and BET surface area was 51.4 m2/g. Their photocatalytic activities were evaluated by degradation of methanol vapor. Photocatalytic activity depended on their crystal structure rather than specific surface area.

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The Ni/Al nitrate form layered double hydroxides (LDHs) were successfully synthesized by chemical precipitation and hydrothermal methods through pH control, the pH effects on the formation of which was studied. It was found that at low pH value, nitrate hydrotalcite was obtained, while at high pH value, carbonate hydrotalcite was produced. Ni/Al nitrate form LDHs particles with good crystallinity and classical hexagonal shape were obtained by hydrothermal treatment and characterized by the scanning electron microscopy (SEM). The transformation mechanism of the Ni/Al LDHs between nitrate and carbonate form under pH control was also discussed.

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TiO2(B) was obtained from glycolate titanium complex by hydrothermal treatment at 473 K for 1 to 72 h. TiO2(B) very fine particles synthesized by hydrothermal treatment at 473 K for 1 h were separated from the solution and re-treated in several condition solutions at 473 K for 72 h with stirring. Particle size and morphology could be controlled by the re-treated. Photocatalytic activity of TiO2(B) samples obtained by hydrothermal treatment were compared with samples obtained by re-treated. The activities were examined in terms of by methanol decomposition of methanol (CH3OH).

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YSZ thin film was fabricated from YSZ precursor solution by using pulsed mode electro-chemical deposition method. The precursor was the water solution of Y(NO₃)₃-6H₂O and Zr(NO₂)₃-2H₂O and NH₃aq. YSZ thin film was deposited on the glass substrate by applying the voltage of 2.5V for 300s, and annealed at temperature of 773K afterwards. It was confirmed that the films crystallization, thickness and defects were depended on the distance between electrode and substrate and also on the pulse frequency of the applied voltage.

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Powder samples of Ba3Ta6Si4O26 having a high photocatalytic activity for water splitting were synthesized in their pure form either by the polymerizable complex (PC) method or by the amorphous metal complex (AMC) method. The photocatalytic activity of the sample prepared by the PC method is comparable to that of the sample prepared by the PC method. The AMC method is advantageous over the PC method in that it involves 5 times less amounts of organics required for the whole process, and thus it can be considered as an environmentally benign process.

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The bulks of mesoporous materials were prepared by the hydrothermal hot-pressing method. The humidity adsorption/desorption efficiency of various mesoporous materials was evaluated. Mesoporous materials had large amount of humidity adsorption and good moisture-retaining property from the capillary force of mesoporous uniform pore-size distribution. These properties were favorable for not only the adsorbent material but also the f fire-retardant material.

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[in Japanese]

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We have succeeded to synthesize a double nitride, NaTaN2 via reaction of a metal Ta and NaNH2 in supercritical ammonia fluid. In Ammonothermal condition, NaTaN2 fine crystal was formed at ≥ 773 K and this reaction was comparatively low temperature process. The products were investigated by using X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy and UV-Vis diffuse reflectance spectra.

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In this study a three dimensional microreactor was used for the synthesis of the silica particles. By using the microreactor the silica particles could be prepared from the water glass-sol by the sol-gel process and thermal treatment. The obtained silica particle size was 54-86μm which greatly depends on the inside diameter and flow velocity of inner flow, so it is easy to be controlled by these parameters.

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Li-doped NiO is known to be p-type oxide semiconductor. In this work, we succeeded fabrication of heavily Li-doped NiO(111) epitaxial thin films on the sapphire(0001) substrate by using pulsed laser deposition at room temperature. The XRD charts and RHEED patterns showed that NiO(111) film fabricated at room temperature was grown epitaxially, but films fabricated at high temperature were grown polycrystalline. Moreover, we found from I-V measurement that the film deposited at room temperature had the higher conductivity than the films grown at high temperatures.

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Transparent conductive aluminum doped zinc oxide (ZnO:Al) films were deposited on glass substrates by electric current heating in vacuum. The structural, electrical and optical properties were investigated. The lowest resistivity of the ZnO:Al films was 2.7*10-4 ohmcm and the average transmittance of the films was about 90% in the visible range.

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We fabricated an epitaxial Al₂O₃/Ni bilayer film on a sapphire substrate using PLD process and selective hydrogen reduction method. The epitaxial Al₂O₃/NiO bilayer film was firstly fabricated by PLD process in low temperatures. Then, the fabricated Al₂O₃/NiO film was annealed in hydrogen atmosphere, and only the NiO layer was reduced to Ni metal layer. As the results, the epitaxial Al₂O₃/Ni (insulator/metal structure) film was obtained. The fabricated epitaxial Al₂O₃/Ni bilayer film exhibited a very smooth surface.

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AlN ceramics have been jointed using a filler synthesized from urea and aluminum chloride hexahydrate. The filler material is transformed to AlN by heating above 1000˚C for 50 min. High strength was obtained by joining at 1500˚C.

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[in Japanese]

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Characterization of concentrated slurry is the final target to make reliable ceramics. Using concentrated slurry characterized by a micro chemical tip, we made a compact by a centrifugal method. We observed an internal structure of compact and the clear effect of agglomeration of concentrated slurry on the internal structure of compact.

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Organification of layered polysilane was investigated to prepare Si nanosheet. Organification was successfully achieved by reaction of hydrogenated polysilane with n-decylamine. The organized polysilane has finely stacked structure containing n-decylamine between the layers and the interlayer distance is about 3nm, which is about 5 times larger than the original one. The organized polysilane can be exfoliated to become Si nanosheet in dilute solution of chloroform.

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Highly oriented hydroxyapatite with translucency was prepared in rotating a high magnetic field and subsequent HIP treatment. Lotgering Factor (L.F.) as degree of orientation was 0.81 after sintering. The samples showed high relative density and translucency in visible range. The transmittance of the HIPed sample was higher than that of non-HIPed sample. Transmittance of samples was also improved by HIPtreatment.

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Triethylphosphine oxide (TEPO) was accommodated in the interlayer space of a layered perovskite, HLaNb₂O₇·xH₂O , via a reaction with an n-decoxyl derivative of HLaNb₂O₇·xH₂O. XRD pattern of the reaction product showed that the interlayer distance of the reaction product was ca 1.8 nm. In the IR spectrum of the reaction product, no absorption bands due to n-decoxyl groups were observed, and a new absorption band (P=O stretching vibration, 1077 cm^-1) assignable to TEPO appeared.

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A new perovskite-type oxide, Ba0.96Bi0.86O2.59(OH)0.41 was prepared by low temperature hydrothermal reaction using NaBiO3•nH2O and Ba(OH)2•8H2O as starting materials. The crystal structure of this compound was refined by single crystal X-ray diffraction data, and the structure refinement with the space group Pm3m (#221) led to Rw = 0.035 and R = 0.054 for all reflections.

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Silicon nitride (Si₃N₄) ceramics is used for machine components such as rolling bearings and glow plugs. In addition, Si₃N₄ is used in producing processes of aluminum (Al) parts by casting because of its high thermostability and hardness. However, Si₃N₄ is a hard-to-machine material and it is required to machine efficiently and precisely such a hard and brittle material. We used a unique grinding method called "electrolytic in-process dressing" (ELID) for efficient and precise machining. In this research, we conducted efficient and precise grinding of Si₃N₄ ceramics and investigated its surface properties.

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We have successfully fabricated <111>-textured BaTiO3 polycrystals by templated grain growth (TGG) method. The platelike BaTiO3 used as template particles with <111> lying perpendicular to the plate face were prepared by molten salt synthesis via Ba6Ti17O40. The effects of processing parameters on sintered density and the degree of orientation were examined. By employing suitable parameters, the textured BaTiO3 ceramics with the density of 94.5% and the degree of orientation of 0.86 (Lotgering factor) were obtained.

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