Intercalation behavior of n-butylamine in H2La2Ti3O10, a protonated form of Ruddlesden-Popper type layered perovskite, K2La2Ti3O10, was investigated. H2La2Ti3O10 was refluxed in a mixture of 25 ml of dry n-butylamine, 25 ml of dry THF, and 0 - 5.0 ml of water or in a mixture of 25 ml of dry n-butylamine and 25 ml of water. n-Butylamine was intercalated into H2La2Ti3O10 only when the amount of water was equal to or larger than 0.18 ml.

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Preparation and characterization of the titanate films intercalating various metal cations between the titanate layers from transparent titanate sol were investigated. UV irradiation to the titanate films containing chelate complexes could decompose the organic ligand to yield metal ion-intercalated titanate films. The chelation of metal ions would decrease the charge density of the metal ions to reduce the interaction between the titanate sheet and the metal cation, forming the stable sols.

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Mesostructured niobium oxide was prepared by ion exchange reaction using layerd perovskite K₂NbO₃F and C12, C16, C18-alkyltrimethylammonium(CnTMA) surfactants. Lamellar-type niobium oxide-CnTMA complexs were synthesized at 70°C in high pH (10-11) solution for n=16 and 18 and they transformed to 2d-hexagonal-type complex by the treatment in low pH (4-5) HCl solution. For n=12, hexagonal-type complex was synthesized even at high pH condition.

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Porous AlN was fabricated by carbothermal reduction-nitridation of AlN polytypoid of Si-Al-O-N system. The Thermal conductivity depended on not only the porosity but also the microstructure. In particular, porous AlN ceramics fabricated from the AlN polytypoid with 10wt% SiO₂ addition had high thermal conductivity (50W/mK), high porosity (54%) and low dielectric constant (3.0 at 1MHz). Consequently, this porous AlN ceramics is expected to be used under a high frequency.

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A raw material for Si-O-C ceramics is polysiloxane precursor, i.e., silicone resin, which is solid, molten, cross-linked, and pyrolyzed in the order from room temperature to 1000°C. A new process for producing Si-O-C ceramic foams has been developed based on polymer direct melt foaming process, by using chemical blowing agent and catalyst which accelerates the cross-linking of silicone resin. The successful production method was established through controlling the viscosity of silicone resin by catalyst at the decomposition temperature of chemical blowing agent.

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Translucent conductive porous glass was prepared by depositing tin oxide on the inner surface of the pores of a porous glass plate and its outer surface by chemical vapour deposition method. The lowest resistivity along the outer surface of the translucent conductive porous glass is in the order of 10^-1 Ωcm. Resistance between the two outer surfaces of the treated porous glass plate is about 300 kΩ. Conductivity between the two outer surfaces of the treated porous glass plate was confirmed for the first time.

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Alkoxide-derived silica gel films were deposited on silicon substrates, and heated at a constant rate in a near infrared image furnace, where in situ observation was made using an optical microscope. Gel film deposition and heat-treatment were conducted in controlled humidity. It was found that the cracking of the films occurred in the heating-up stage, and that the cracking onset temperature shifted to lower temperatures as the humidity increased. The film thickness was found to slightly decrease with increasing humidity while the porosity of the films was almost unchanged.

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Gel films were deposited on silicon wafers using Ba(CH₃COO)₂-Ti(OC₂H₅)₄ solutions with and without polyvinylpyrrolidone (PVP). In situ stress measurement was conducted on the films during heating up to 500°C at a constant rate of 5°C min^-1 and cooling down to room temperature. For the film prepared without PVP, the stress decreased with increasing temperature, turned to compressive one over 250°C, turned again to tensile one at 330°C, and increased to ca. 200 MPa at 400°C. On the other hand, for the film prepared with PVP, the tensile stress decreased with increasing temperature up to 250°C, and increased again with increasing temperature, showing the maximum value of 90 MPa at 400°C. On cooling from 500°C, both films basically showed increase in stress with decreasing temperature. The remanent stress at room temperature was 90 and 350 MPa for the films prepared with and without PVP, respectively.

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Spin-coating was conducted on silicon wafers using xylene solution of polysilazane as the coating solution. The films obtained were exposed to vapor of various acidic and basic solutions at room temperature. Durability of the films in hot water was examined by evaluating the reduction in thickness on immersing the films in distilled water at 80°C. The film just dried in the ambient atmosphere showed reduction in thickness from 0.13 to 0.03 micron when soaked in the hot water for 1 day. The films placed over NH₃ aq. or C₂H₅NH₂ aq. for 18 h, on the other hand, showed no reduction in thickness even when soaked in the hot water for 5 days.

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Al-doped ZnO films were prepared on silica glass substrates using Zn(CH₃COO)₂·2H₂O-AlCl₃ solutions containing polyvinylpyrrolidone(PVP) as the coating solution. Dip-coating and firing were not repeated, performed just one time. The gel films were heated at 100°C for 10 min, at 300°C for 10 min and at 800°C for various periods of time. The thickness decreased from 0.35 to 0.3 micron with increasing heating time at 800°C up to 60 min. The resistively of the films decreased from 10⁰ to 10^-3 ohm cm with increasing heating time at 800°C up to 900 min.

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Sol-gel derived hafnia films were hardened by ultra-violet irradiation with a high-pressure mercury lamp. The hafnia sol A was prepared by the hydrolysis of HfCl₄ in ethanol with H₂O and HNO₃, and the sol B was prepared by the hydrolysis of hafnium hydroxide with H₂O and HCOOH. The gel film obtained from the sol A was hardened to 9H by the pencil method of the scratch hardness after the UV-irradiation of 30 min. The irradiation time, however, was shortened to 10 min in the case of the film obtained from the sol B.

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Hardening processes of sol-gel derived hafnia gel films by UV-irradiation were investigated by temperature programmed desorption (TPD) and FTIR. The FTIR spectra of the films before and after the UV irradiation showed absorption peaks at 1595 and 1374 cm^-1, indicating that HCOO^-ions in the gel films coordinated to Hf ions. The TPD analysis of the gel films showed that H₂O and HCOO^-ions contained in the gel films even after UV-irradiation.

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Firing processes of sol-gel derived titania films were investigated by temperature programmed desorption (TPD). The TPD analysis showed the evolutions of H₂O, NH₃, HCl and Cl from the gel film. Since H₂O evolved in the low temperature region, it was ascribed to the water absorbed on the gel film. The TPD curve of NH₃ generated from the NH₄⁺ion was observed under 260°C. HCl evolved under 300°C and Cl evolved in the temperature range of 50-1000°C.

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Aqueous titanium lactate solutions with a concentration as high as 1 M were obtained by direct reaction of titanium tetraisopropoxide with lactic acid. When aqueous ammonia was added to the solutions to increase the pH value to 9.0-9.5, colloidal solutions were obtained from which (004) preferentially oriented anatase films with refractive index of 2.54 were prerared. Patterned TiO₂ films were also obtained from the solutions by photoirradiation to gel films.

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We have demonstrated formation of micro-dots on the surface of densified silica glass by thermal relaxation. The glass surface reached enough high temperature to induce structural relaxation by continuous irradiation of beam pulses from a CO₂ laser. Distribution of temperature on the irradiated surface owing to beam profile and thermal diffusion is inferred as the origin of bump shape.

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Crystallization behaviors of xK₂O-xNb₂O₅-(100-2x) GeO₂ glasses and deformation behaviors of their crystallized glasses were examined. Good transparent nano-crystallized glasses were easily obtained in the sample with x=25, but crystallized glasses with x=20 and 30 were opaque. The second harmonic generation was not observed in the crystallized glasses, indicating that the crystalline phase is not a nonlinear optical KNbGeO₅ crystal. It was found that the universal hardness obtained by nanoindentation experiments increases due to the nanocrystallization.

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The methodologies for the preparation of the functional glasses through anodic oxidation have been developed. The nanometer size pore array was formed by the anodic oxidation of aluminum sputtered on the glass surfaces. The introduction of active components into the pores by sol-gel technique or electro deposition technique has been studied to make the glasses possess the functions like photo catalysis, nano size magnet array etc. The glasses having the nanostructure on the surface shows good translucence and are suitable for optical applications.

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Au nanoparticles embedded in poly vinyl alcohol (Au/PVA) films on slide glass substrates were prepared by a photoreduction technique. In the presence of ethylene glycol in the films, Au nanoparticles were effectively formed by the UV irradiation. The mean diameter of Au nanoparticles in PVA was estimated to be 37 nm. When the Au/PVA films were immersed in various types of alcohols with different refractive index (n_D), the surface plasmon resonance absorption peak were shifted toward a longer wavelength with increasing n_D of the alcohols. These properties are used for a new type optical sensor.

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CdTe-MPS((3-Mercaptopropyl)trimethoxysilane)-nanocomposite glass has been prepared by using a sol-gel method to fabricate a new type of phosphor. The prepared composites show the same photoluminescence spectra as those of solution both in the case of green and red emission. This ascribed to the existence of a thiol group in MPS.

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Au-nanoparticle dispersed TiO₂ (Au: TiO₂) films were prepared by laser ablation (pulsed laser deposition) using Au-powder mixed TiO₂ sintered targets. Au concentration in the film was controlled by target composition. A mean diameter of Au particles was increased up to 4.0 nm after heat treatment. Optical absorption spectra due to surface plasmon resonance were observed at a wavelength around 630 nm. The crystallization of Au particles and TiO₂ matrix caused the enhancement of absorption coefficient and shift of absorption peak wavelength, respectively.

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The total structure factors, S(Q), of vitreous silica by high-energy X-ray diffraction technique around the glass transition temperature, T_g(=1180°C), to investigate the difference of intermediate-range order. The intensity of the First Sharp Diffarcion Peak (FSDP) at 1060°C is almost same as that at room temperature, though the peak position shifts slightly to lower Q, due to small thermal expansion. On the other hand, the intensity of the FSDP at 1345°C is smaller than that at 1060°C. It indicates that the small modification of the intermediate-range order is observed around the glass transition temperature.

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We observed liquid-liquid phase separation of glass under microgravity by in situ observation method. The glass of the system BaO-B₂O₃ were prepared by a meltquench method. The nucleation and growth of phase-separated particle under microgravity is slower than under 1-g. The delay time of phase separation between under microgravity and under 1-g depends on flow rate of the melt under microgravity.

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Copper ions were implanted in silica glass following the halogen ion(Cl, Br or I) implantation. Optical absorption and X-ray absorption spectra were measured for these glasses. Cu ions were coordinated with oxygen ions in the as-implanted glass. CuCl, CuBr and CuI crystal line compounds were formed in silica glass after heating to 1000-1100°C

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Structure and electrical properties of In-Zn-O films deposited by pulsed laser deposition were investigated. All films prepared at substrate temperatures up to 573 K were amorphous. The resistivity showed a minimum around an oxygen pressure of 1.3 Pa and decreased with increasing substrate temperature. The lowest resistivity was 2.89 × 10^-4 ohm cm at 573 K under 1.3 Pa.

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The amorphous films in the ZnO-In₂O₃ system deposited by a facing-target DC magnetron sputtering technique exhibited increased carrier concentration and decreased Hall mobility after the annealing. These parameters counteracted each other so that the resistivity remained unchanged. Post-annealing under the reductive gas flow was effective only on improving unevenness of the amorphous films.

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Thermal decomposition process of indium carboxylates in dry gas and high humidity atmospheres was investigated by using TG-DTA-MS and XRD-DSC coupled with humidity generator. Crystalline indium oxide was obtained below 3000°C in high humidity atmosphere.

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TiO₂ and BaTiO₃ gel photonic crystals are successfully made by using high-concentrated sol-gel method and resist molds. These gels contained polyethylene glycol as a plasticizer. We investigated nano structures and optical properties of obtained gel materials by TEM, XRD, FT-Ir, DTA/TG and UV-VIS. These gels contain nano crystals and have very high transparency and relatively high refractive index (1.7-1.9).

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Three-dimensional photonic crystals with periodic variation of dielectric constant were fabricated by rapid prototyping method called stereolithography. Millimeter-order epoxy lattices with a diamond structure were designed to reflect electromagnetic waves by forming an electromagnetic bandgap in the GHz range. We tried to control the bandgap position by changing the volume fraction of dielectric medium from 14∼86%. The band diagram was calculated by means of plain wave expansion method.

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Millimeter order photonic crystals composed of epoxy lattices including titania-based particles with a three-dimensional diamond structure were fabricated by using a stereolithograpy of CAD/CAM process. The diamond lattice structure formed a perfect bandgap to microwave transmission, while the directional diamond structures with stretched lattice spacing showed the directional transmission of microwave. Stretching ratio of the lattice spacing was changed according to the band calculation using a plane wave propagation method. A microwave antenna head composed of normal and stretched diamond structures was fabricated which can realize the unidirectional transmission.

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Bulk ceramics and thin films of yttrium niobate (YNbO4) were prepared and their electro-luminescence (EL) was measured as function of electric field. Thin films were prepared by RF-sputtering process. For the EL measurement of thin films, Nb-doped SrTiO3 single-crystal substrates were used as a bottom electrode and Al-doped ZnO transparent films were used as a top electrode. EL was observed by applying electric filed between the two electrodes. Central wavelength of the photo luminescence of the thin films was 400 nm. The EL intensity increased with applied field.

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We have investigated novel optoelectronic properties in oxides. At focus are photo-induced structural changes in strongly correlated electronic systems, which may occur though electronic excitation by light irradiation. Cu-based high-temperature superconducting oxides, which have the rich electronic and structural phase diagrams, are chosen as candidates for the pursuit of photo-induced structural changes. Photo-induced phase control with superconducting properties is established and applied for creating novel optoelectronic functions, such as optical memories and switches, as well as new fabrication procedures for superconducting components.

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Highly-ordered, transparent, 2-dimensional hexagonal mesoporous silica thin films have been synthesized by an acidic sol-gel self-assembly chemistry using a triblock copolymer as surfactant and aging as-made samples under water vapor hydrothermal conditions. Using the mesoporous silica films as support, the patterning of rhodamine 6G-doped mesostructured silica can be made by soft lithography. The laser actions in the waveguides are investigated in this report.

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An effect of Au coating on ZnO growth during CVD process has been studied. The Au coating on substrate is effective to changesurface morphology ot ZnO thin film. The presence of Au on the ZnO surface was not detected by SAM and SIMS, indicating that there is no Au migration during ZnO growth. It is considered that Au acts the nucleation of ZnO.

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In order to clarify the role in the grain boundary of bismuth, the reactivity of a zinc oxide single crystal and bismuth oxide content glass was investigated. Bismuth content glass wets zinc oxide single crystal well. The contact angle of the bismuth content glass and zinc oxide single crystal is about 10 degrees.

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ZnO/(Zn, Mg, Al)O modulated structures were synthesized on A-phase of sapphire by pulsed laser deposition. X-ray diffraction measurement revealed that the grown films had superlattice structure as designed.

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Metastable point defects play important roles in ceramic materials, e.g. they act as carrier in zinc oxide thin films. To clarify these roles the metastable defects are introduced with Ar-ion implantation in zinc oxides, and characterized with oxygen diffusion experiment and luminescence. The oxygen diffusivity was reduced by lower Ar-ion dose, and then was increasing with increasing dose amounts. On the contrary photo-luminescence was not detected in the lowest dosed samples.

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Undoped zinc oxide (ZO) and aluminum doped ZnO (AZO) films were grown using MBE. The growth rate and the electric properties were changed with the growth condition such as the growth temperature and the Zn/O supplying ratio. In the AZO films grown with the optimized growth conditions, the carrier concentration and Hall mobility were above 10²⁰cm^-3 and about 60cm²V^-1s^-1, respectively. The AZO films showed characteristics of degenerate semiconductors. The optical properties of these films were investigated by temperature dependence cathode luminescence spectra. The AZO film gave UV emission, which is not assignable to excitonic emission.

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ZnO thin films were fabricated on sapphire substrates by pulsed laser deposition using NO₂ as oxidant. With increasing growth temperature, the FWHM values of ω scan decrease. ZnO films grown in NO₂ showed low carrier concentration when compared to the films grown in O₂ atmosphere.

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We found a magical way to grow single-crystalline film of natural superlattice oxides, named “Reactive Solid-Phase Epitaxy Method”. The method is very unique and easy way using an atmospheric oven. Almost perfect single-crystalline superlattice films are grown self-assembly by heating of a bi-layered structure deposited on a substrate, which is composed of an extremely thin (∼2nm^†) epitaxial layer and a thick (∼150nm^†) randomly-oriented polycrystalline layer of a natural superlattice oxide, in an atmospheric oven. In this paper, we demonstrate the capability of the present method. We chose homologous compound of InGaO₃(ZnO)_m (m=integer) as an example of complex oxides with natural superlattice structure.

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In order to clarify the growth mechanism of single-crystalline thin film of InGaO₃(ZnO)_m by reactive solid-phase epitaxy, we investigated the structural changes of the InGaO₃(ZnO)₅/epi-ZnO bi-layer grown on (111) YSZ during high-temperature annealing using HREM. The ZnO epitaxial layer is no longer detected when it is annealed at 1000°C while a 50nm-thick single-crystalline InGaO₃(ZnO)₅ layer was formed just from the substrate surface. It implies that the solid-phase reaction between the polycrystalline InGaO₃(ZnO)₅ and the ZnO epitaxial layer occurs at temperatures greater than 1000°C, which leads to the formation of the epitaxial layer. Finally, an almost perfect superlattice structure of InGaO₃(ZnO)₅ is formed over the entire area of the film after the annealing at 1400°C.

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Solid solution ceramics, SiAlONs are technologically important, because of their unique combination of thermal and mechanical properties, as well as high chemical inertness. However, the distributions of the solute Al and O are not fully understood. The local environments of the cations have been investigated using MAS-NMR and EXAFS. Both of these results suggested the bond-preference in SiAlONs. In the present study, atomic arrangements of SiAlONs are investigated by first principles plane wave basis pseudopotential method. Energetics on the bond-preferences is made using the systematic SiAlON models within the primitive cell of β-Si₃N₄.

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The joining of sapphire single crystal plate to alumina ceramic tube is fabricated successfully using 34CaO-30Al₂O₃-36SiO₂ glass as an interlayer. This glass showed fine adhesion performance to alumina ceramics and sapphire single crystal and rapid penetration through the grain boundaries of the alumina ceramics. The joint with no crack was obtained by heating at 1550°C for 10 min and slow cooling from 1200°C to room temperature. From the thermal shock test, the half of the specimens showed the cracks after quenching from 225°C to 0°C, but all specimens showed no crack after quenching from 200°C to 0°C. The specimen composed of alumina tube - sapphire plate -alumina tube showed the compatible bending strength to the specimen composed of alumina tube -alumina tube.

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The previous presentation reported that nearly theoretical density of alumina sintered bodies could be obtained within 1 min of duration time by microwave plasma technique. The present presentation will describe that alumina sintered body showing translucency, with high density, and homogeneous microstructure were obtaining using stating alumina powder with high purity.

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A number of studies for high temperature deformation and flow of polycrystalline structural ceramics have been conducted, since the pioneering works of Nabarro, Herring and Coble. However, several problems remain unsolved in the deformation and flow of ceramics materials. High temperature deformation of polycrystalline structural ceramics are usually characterized by a “viscous” liquid via Dorn equation. The aim of the present study is to establish the science and physics of deformation and flow of polycrystalline ceramics without utilizing the concept of “steady-state”.

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Al₂O₃/YAG unidirectionally solidified eutectic crystals were prepared by Bridgman method. Orientation relationships in the two phases were investigated by means of macroscopic (X-ray diffraction) and microscopic (electron diffraction) methods. Electron diffraction by TEM revealed that the growth direction of YAG was <100> crystallographically. The results of TEM observation showed that alumina had boundaries in crystal.

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Plate shaped Al₂O₃/YAG MGC materials of eutectic composition was fabricated by Bridgman method using for the Morybdenum mold. In spite of the same speed of 5mm/hr at the descend speed of a mold, the microstructure was smaller than that of a φ40mm rod sample. The strength of the plate was equal and more than the rod sample.

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Crystal orientation of Al₂O₃/GdAlO₃(GAP) MGC materials was investigated by the Laue and the Pole-figure method. The growth direction of Al₂O₃ phase and GAP phase were determined to be about 10° tilted from [110] and 5-20° tilted from [111], respectively. Both Phases showed single crystal orientation.

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In order to develop dense mullite ceramics, the effect of particle size on the sintering characteristics and the resultant microstructures was investigated using kaolin and alumina as starting materials. Mullite ceramics with relative density larger than 97% were obtained by firing at 1650°C, using elutriated kaolin and submicron corundum powders or alumina sol. Particle size of alumina affected on the microstructure of dense mullite polycrystals.

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The effect of Al₂O₃ addition on the phase structure of ZrO₂ in the Al₂O₃-ZrO₂ system was investigated. Al₂O₃-ZrO₂ composite powders with 15wt%, 50wt% or 85wt% Al₂O₃ were prepared by mixing α-alumina powder with Zr(OH)₄ gel that was synthesized by the precipitation method. The resulting mixtures were calcined for 2h at various temperatures from 400°C to 1300°C. At the addition of 85wt% Al₂O₃, metastable t-ZrO₂ with grain size of less than 11nm was obtained after calcinations at temperatures ranged from 500°C to 750°C, whereas at the addition of 15wt%, or 50wt% Al₂O₃, the volume fraction of monoclinic zirconia continuously increased with increasing calcination temperature. It is indicated that alumina with high content can effectively inhibit the nucleation and the grain growth of zirconia.

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The effect of glass content on deformation of Y₂O₃-SiO₂-Al₂O₃ doped (YAS) or SiO₂ doped (Si) Y-TZP was studied at high temperatures. The flow stress decreased gradually in Si-doped Y-TZP. The flow stress decreased significantly with small amount of glass in YAS-doped Y-TZP. This difference is supposed to be related with the area fraction of zirconia-glass interface that is determined by dihedral angles at multi-junctions.

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