A new family of electrochemical cell for NOx decomposition in the presence of excess oxygen have been designed and investigated as shown below. (Electro-catalytic electrode (NiO+YSZ)) | Cathode (Pt+YSZ) | Electrolyte (YSZ) | Anode (Pt+YSZ) The small NiO and Ni particles were observed at the interfaces between the NiO/YSZ after cell operation. It might assume that increasing the reaction sites by small NiO and Ni particles generation improved the deNOx performance.

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Cerium and zirconium alloy was fabricated by arc melting method. Inert gas condensation method combined with a co-evaporation process and uneven bar system is employed to synthesize the ceria-zirconia solid solution based single nano sized composites. High-resolution TEM, SEM and cotalytic measurements have been used to characterize the samples and study the synergistic effect between the catalyst phase and the ceria-zirconia solid solution.

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Hexaaluminogallate/yttria-stabilized zirconia system has been studied for the application of direct No_x reduction system without any reductant gases. The hexaaluminogallate powders prepared by coprecipitation method revealed effective NO oxidation to the activated NO_x state in NO/O₂. In this study, direct NO_x reduction of the hexaaluminogallate/solid oxide electrolytes laminates was investigated.

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Dielectric Barrier Discharge (DBD) plasma treatment is a promising and effective method for reduction of NO_x in an oxygen rich environment. Dielectric material plays a very important role on the deNO_x behaviour. Experiments showed that deNO_x behaviour in a plate type reactor greatly changed depending on the properties of dielectric materials. In the case of quartz and silicone rubber, more than 99% of 400 ppm NO could be removed with 0.084-0.168 second of residence time. On the other hand, in the case of alumina, NO_x increased to a relatively high level since the reaction between nitrogen and oxygen significantly proceeded.

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Recently, various porous ceramic films have been studied extensively. The applications to gas purification and size selective catalyst can be achieved by the synthesis of films with through channels perpendicular to the film surface. In this work, the synthesis of Ti02 film with one-dimensional nano structure was attempted by the eutectic decomposition of amolphous Ti-Cu-O films prepared by Rf sputtering, and then heat-treated at 700°C for 2h in 02 atmosphere and etched. SEM observation revealed that the prepared TiO2 had columnar structure with 150 nm diameter.

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Porous ceramics powders expected to have wide applications from catalytic to electronics. However, it is difficulty to maintain the pores up to high temperature. This work tries to study the possibility of producing porous oxides powder with thermal stability. Porous TiO2-P2O5 nanocomposite powders have been synthesized by sol-gel method in the presence of tri-block copolymer (EO)20(PO)70(EO)20 (Pluronic123). The TiO2 nanocrystals with a diameter of 3.6 nm precipitated in the as-synthesized materials in the presence of surfactant at 80°C considerably lower than those for traditional heat-treatment in the solid state, the nanocrystal was anatase but maintained the same size upon calcinations in the temperature range of 400-500°C.

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Titania coated silica aerogels were prepared by soaking of silica wet gels in titanium alkoxide solutions and following supercritical drying. Obtained aerogels showed the specific surface area values of 600-700m2/g, which were larger than those of pure titania aerogels. The effects of soaking solvent, supercritical drying medium, and etc. on titania coating are discussed.

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Hollow TiO2 microspheres have been successfully fabricated from PMMA (core)/TiO2 (shell) composite prepared with a mechanofusion system. The dense and smooth-surfaced shell wall consisted of well-sintered TiO2 particles was obvious after calcination at 1200°C for 6 h when as-received TiO2 was used as a starting material. The surface of the shell wall became rather rough and attachment of fine particles was significant with increasing the MgO content in the starting material. Especially, perfect hollow microspheres were hardly obtained above 40wt% MgO.

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Clay bodies containing 2 mass% Fe2O3 were fired at 1250°C in air, CO2 and CO2-H2. The relationship between color and chemical states of iron in fired bodies was studied by ESR, reflectance spectra and XPS. Color of the sample fired in air was dark yellow. Brown surface of fired body was obtained by heating in reducing atmosphere followed by cooling in oxidizing one.

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This study deals with the colouration mechanism of hard oxidizing fire iron red glaze. While there are some suggestions on the substance of red colour in this glaze, there is no scientific explanation yet. Consequently the red colour is attributed from Fe2O3 which comes from the replacement of Fe3+ by Mg++ and Na+ in calcium iron phosphate(Ca9Fe(PO4)7) of hard oxidizing fire iron red glaze.

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The effect of characterization of Fe2O3 particles on the color of α-Fe2O3 powders was evaluated. Several kinds of commercial α-Fe2O3 powders for red pigment in porcelain products were used. Morphology and mean particle diameter of the powders were observed by transmission electron microscopy (TEM). Color of α-Fe2O3 powders was estimated by spectral reflectance measured using spectrophotometer. The impurity contents of the powders were analyzed using ICP and fluorescent X-ray analysis. These results indicated the color of α-Fe2O3 powders was dependent on particle size distribution and impurity contents of the powders.

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In recent years there has been increasing environmental and financial pressure to recycle (waste) materials. Some recycled materials are simply 're-used' for the purpose for which they were originally manufactured. However, the usual process for recycling waste glass is by melting and sintering, which are undertaken at high temperature (>1000°C and 700-900°C, respectively), but with a high financial cost. In contrast, hydrothermal processes at low temperature (e.g. 150 - 300°C) have potential to produce new crystalline materials. The production of (new) crystalline materials by hydrothermal techniques is now possible, with obvious cost and environmental benefits.

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Precursors for silicon carbide were prepared from poly(methylsilane) via hydrosilylation reaction using p-diethynylbenzene and triethynylborazine as cross-linking reagents (cross-linking reagent / Si=0.05). The proceeding of the hydrosilylation reaction between ethynyl groups of cross-lonking reagents and SiH groups was investigated by IR and NMR analyses. Ceramic yields of the cross-linked products using p-diethynylbenzene and triethynylborazine increased from that of poly(methylsilane) (23 %) to 73% and 84%, respectively.

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Precursor fibers for SiC based fibers were synthesized from Polycarbosilane (PCS) - Polymethylsilane (PMS) polymer blends. Addition of 0.5 mass% PMS can be melt-spun. Addition of 20 mass% PMS, however, requires an addition of a cross-linking inhibitor for melt-spinning. PMS addition is generally effective to increase resultant ceramic yields and to maintain fiber strength after high temperature exposures. In the PMS containing precursor fibers, a holding at 573K during the pyrolysis process is remarkably effective to increase the ceramic yield and the strength. PMS probably acts as a cross-linking agent at 573K to combine PCS chains.

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Alkoxytrichlorosilanes (CnH2n+1OSiCl3; CnOTCS, n = 12－20) were synthesized by the reaction of the corresponding n-alcohols with tetrachlorosilane (SiCl4). Partial hydrolysis of CnOTCS followed by the polycondensation led to the formation of novel layered silica -organic nanocomposites. It was found that the products were composed of organic layers and silica layers stacked alternately on a nanometer length scale, and the basal spacings of the products increased linearly along with the increase in the alkyl chain length.

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Novel mesostructured silica-based hybrids were prepared by using alkylsiloxane oligomers containing three trimethoxysilyl groups [C_nH_2n+1Si(OSi(OMe)₃)₃, n = 10 or 16] as single precursors. The formation of lamellar and hexagonal-like mesostructures for n = 16 and 10, respectively, was confirmed by XRD and TEM. In the case of n = 10, the hexagonal structure was almost retained even after calcination to remove organic groups. The N2 adsorption measurement revealed that the product was microporous silica with high surface area and relatively narrow pore size distribution.

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For fabrication of iron oxide films, We used organo silane self-assembled monolayer films as a template. By patterning the surface functional group of the organic film, we tried patterning thin film using the difference in the interaction of the thin film which grows and a surface functional group.

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The liquid crystal molecules in inorganic-organic hybrids with silica matrix, were aligned by applying electric field. Order parameters of liquid crystal molecules in the hybrids were measured by polarized FT-IR spectroscopy. From the measurement, it was found that the order parameters of the liquid crystal molecules in the hybrids were about 20%.

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Phase-separated siloxane gels with co-continuous porous structures in the length scale from nanometers to micrometers have been synthesized in confined spaces especially in short cylindrical pores within porous medium. Morphology of the phase-separated gels derived from both methyltrimethoxysilane (MTMS) and tetramethoxysilane (TMOS) inside the porous medium was significantly affected by preferential wetting by siloxane phase on the internal surface of the mold. When spinodal wavelength of the guest gel becomes larger than pore size of the porous medium, wetting transition has been observed in the systems with strong affinity between siloxane phase and the internal surface of the mold.

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We investigated behavior of phase separation in a system with silicate and poly(vinylalchol) (PVA). Tetraethoxysilane (TEOS), colloidal silica and water glass were used as silica sources. Silica gel samples were prepared by mixing one of the silica sources and aqueous nitric acid solution containing PVA with vigorous stirring. Only in a system with water glass, phase separation could be induced, so that white opaque gels with macropores were prepared. In this system, macromorphology and size of domain varied by stating composition. These features imply that phase separation in the system with silicate and PVA proceeds into a phase rich in silica and polymer and that rich in solvent.

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Plates of silica gel were prepared by a sol-gel method, and their applicability as a heat insulator was investigated. Bimodal porous silica had high porosity over 90%, and thermal conductivity of it was as low as that of air. Macropores were effective in gas transportation and mesopores which had size of between about 1.7 and 15 nm had the function of humidity control. Therefore, it is considered that the bimodal porous silica is expected as a new multi-functional heat-insulator with both function of insulation and humidity control capacity.

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Filled with of porous silica and porous alumina were prepared from mixed solution of CTAB-H2O-TEOS. Attempts to pack silica homogeneously in the pores of alumina. N2 gas permeated through the composites.

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Recently, much attention has been given to the development of novel porous materials because of their potential wide-ranging applications in catalysis, adsorption, nanotechnology, etc. In this study, we synthesize the silica fibers by sol-gel condensation using agar with other organic compounds as template. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) before and after calcinations are used to obtain visual insights into the silica structure. Formation of silica is fibrous and there is no hole in the silica fibers.

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Silica gel films were prepared on Si wafers by spin-coating using solutions of molar compositions, Si (OC2H5)4: H2O : HNO3: C2H50H = 1 : 2 : 0.01 : 5, Si (OC2H5)4: PVP : H20 : HNO3: C2H5OH = 1 : 0.5: 2 : 0.01 : 20, and Si(OC2H5)4 : CH3Si(OC2H5)3 : H20 : HNO3 : C2H50H = 0.4 : 0.6 : 2 : 0.01 : 5. The gel films were heated at a constant rate of 5°C/min up to 500°C, where in itu measurement of stress in films were conducted using a thin film stress measurement instrument (FLX-2320, Tencor). PVP or CH3Si (OC2H5)3 in solutions was found to decrease the intrinsic, in-plane stress in films that develops on heating.

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A silica sol was prepared from a solution of mole ratio, Si(OC2H5)4: HNO3: H20 = 1 : 0.01 : 2, which was then diluted with various amounts of C2H50H to obtain sols of various viscosities. Get films 0.06-0.60 μm in thickness were deposited on Si wafers by spin-coating, which were then heated at a constant rate of 5°C/min up to 500°C. In situ measurement of stress in films were conducted on heating using a thin film stress measurement instrument (FLX-2320, Tencor). In-plane intrinsic stress was tensile, increasing with increasing temperature, irrespective of the initial thickness. The dependence of the internal stress on film thickness was basically absent.

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The corumdum-seeded alumina gels were prepared from Al (O-sec-Bu)₃ by the sol-gel method using HNO₃ as a catalyst. Alumina gels were prepared in different batch-scales and were heat-treated for various times at 800°C. The possibility of mass production was examined by comparing their crystallization behavior. As a result, each gel was completely transformed to α-alumina at 800°C, but the gel from a larger batch required a longer heat-treatment time for complete α-transformation.

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Isotopic exchange of ¹⁸O with¹⁶O in sol-gel derived titania films containing ¹⁸O was investigated by temperature programmed desorption (TPD) and secondary ion mass spectrometry (SIMS). The TPD experiment showed that oxygen evolved only in the form of the adsorbed water : the TPD curves of M/z=18 and M/z=20. The ratio of ¹⁸O to (¹⁸O +¹⁶O) was 13at.%. SIMS profiles of ¹⁸O and ¹⁶O in a titania film fired to 350°C in a TPD apparatus were measured. The ratio of ¹⁸O to (¹⁸O +¹⁶O) in the film was 14at.%.

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To obtain porous titanium dioxide films, the dip-coating solution was prepared by hydrolysis of Ti isopropoxide and then complexed with trehalose. The porous titanium dioxide film was prepared by dip-coating technique on glass substrate with this solution. The film was composed of nano sized particles (20 nm). The films were calcined at various temperatures for 30 min. XRD analysis showed that the films heated up to 400-650°C were crystalline in the anatase phase. The film heated to 700°C showed the rutile phase.

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Transparent mesoporous silica thin films were successfully prepared on glass substrates by spin coating method. The precursory solution were prepared by hydrolysis of tetraetylorthosilicate (TEOS) and titanium tetoraisopropoxide in the presence of cetyltrimethylammonium bromide (CTAB) as the template at room temperature. Transparent mesoporous silica-titania thin films were successfully prepared on glass substrates by spin coating method. The content of titania was a maximum of 20wt% to silica.

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In order to elucidate the relationship between the structures of chemical modification reagents and the absorption bands of photosensitive gel films, ZrO₂ gel films were prepared from zirconium butoxide with chemical modification reagents containing ester groups. It has been found that the absorption bands of the gel films are shifted to shorter wavelengths than that using acetylacetone containing two ketone groups.

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ZrO2 precursor solutions were prepared using a zirconium alkoxide (Zr(OnBu)4) and acetylacetone. The crystallinity of the 400°C-annealed ZrO2 thin films was enhanced by acetylacetone addition and UV irradiation using an ultra-high pressure mercury lamp. The effects of UV irradiation on the crystallinity of thin films have changed by amounts of acetylacetone. It was suggested that the orientation of polymerization, degrees of polymerization and the stability of non-crystalline thin films on UV irradiation have changed by amounts of acetylacetone.

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Sol-gel derived hafnia films were hardened by ultra-violet irradiation using a low-pressure mercury lamp. The hafnia sol was prepared by the hydrolysis of hafnium hydroxide with H2O and HCOOH. The gel film was hardened to 9H as determined by the pencil test of scratch hardness immediately after UV irradiation at 16W for 40 min or longer, whereas the hardness of the films immediately after UV irradiation for less time was lower. The hardening process through UV irradiation was analyzed by temperature programmed desorption (TPD).

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Firing processes of sol-gel derived hafnia films were investigated by temperature programmed desorption (TPD). The TPD analysis showed the evolutions of H2O, O2, NO and NO2 from the gel film. Since H2O evolved in the low temperature region, it was ascribed to physically adsorbed water of the gel film. The TPD curve for O2 showed two peaks at 265 and 570°C. XPS analysis of the gel and a film fired to 650°C in a TPD apparatus revealed the atomic ratio of Hf to O in the hafnia films to be 2.22 and 1.84, respectively. These results indicate that the hafnia film lacked O after being fired in vacuum. The evolved NO and NO2 were generated from HNO3 used in the sol preparation.

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In the present study we combined two results, which related with soft solution processing, one is the "Dual Anode System" for direct fabrication of LiCoO2 films on various substrates, the other one is the direct fabrication of photo catalysis thin films using hydrothermal method. They, therefore, enable to deposit the films directly on various substrates, enable to direct fabrication of NaTaO3 thin films for the first time. The treatment, as the above mentioned, with cobalt and target metal electrodes led to the formation of apparent black films on the target electrode (Pt, Ni and graphite). Also, the fabricated NaTaO3 thin films have good photo catalysis activity.

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Submicron particles of potassium niobate KNbO3 were prepared by new colloid chemistry method. A rock-salt-type KF block in a layered perovskite, K2NbO3F, with a K2NiF4 type structure was selectively dissolved in water to produce niobate nanosheets at room temperature. The self-assembly between niobate nanosheets in a colloidal solution produce the nano powder of potassium niobate.

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SrTiO₃/Nb:SrTi0₃/SrTiO₃ layered film could successfully be prepared on LaNiO₃ electrode prepared on SiO₂ substrates by chemical solution deposition method. SrTiO₃/Nb:SrTiO₃/SrTiO₃ layered film exhibited reproducible non-linear J-E characteristics and these results lead to the realization of novel electronic device composed of only ceramics through CSD.

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Single crystals of Na-Nb double ethoxide were synthesized from a mixed solution of Na ethoxide and Nb ethoxide in inert atmosphere at room temperature. The obtained single crystals were colorless and plate like. The single crystals were converted into NaNbO₃ by heat treatment. The crystallized NaNbO₃ particles were obtained by heating at temperatures over 350°C, and well-crystallized NaNbO₃ particles were obtained at 400°C. The mean particle size of NaNbO₃ heated at 400°C for 1.5h was 57nm(D₂₁₀). These results show that NaNbO₃ nano particles were obtained by heat treatment at low temperatures of the single crystals of Na-Nb double alkoxide.

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Barium titanate thin films have been prepared using the barium titanate nano-sized particles dispersed solution. In this study, we made barium titanate thin films at various heat treatment temperature, and the characteristic evaluation was carried out. Then , the dielectric constant was improved at 750°C, and the dielectric loss was improved at 550°C. We think these results suggest that grain size was increased at 750°C, and residual organic group and -OH group were decreased at 550°C.

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Formation of fibrous ZrO₂ has been attempted from a suspension of monodispersed ZrO₂ particles. The monodispersed zirconia particles were prepared by hydrolysis of Zr(OBu)₄ in ethanol with hydrochloric acid as catalyst. Fibrous ZrO₂ with about 1.5 cm of length and 71 to 151 μm of width was prepared by drying the ethanol suspension of the monodispersed zirconia particles. The crystallization and phase transformation of ZrO₂ fibers by heat treatment were investigated by XRD and microstructures of the fibers were observed by SEM. The ZrO₂ fibers consisted of densely packed particles. Although the as-prepared fibers were amorphous, they started to crystallize into tetragonal and monoclinic phases at around 440°C.

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Thermal expansion properties, in the temperature range of 298∼1173K, for the synthesized cubic Cs-Na-leucite compounds (Cs_0.9-xNa_xAl_0.9Si_2.1O₆,x=0.05∼0.30) were examined by high-temperature powder XRD. The thermal expansion rates of the Cs-Na-leucite compounds were found to vary with the chemical compositions, which decreased with increasing the space ratio. The mean thermal expansion coefficient of the cubic Cs-Na-leucite compound having the space ratio of about 46.6% was 0.24 × 10^-6 / K^-1 in the range of 473∼1073K. The result shows that the subsutitution of Na⁺ ions for the Cs cites in Cs-Na-leucite was effective in lowering the thermal expansion rate.

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The influence of annealing effects to recover ferroelectric properties of PZT thick layer formed on SUS304 substrate by Aerosol Deposition Method was investigated. After annealing at 500 for 5min, PZT thick films with the thickness less than 2μm have good ferroelectric property, which was remnant polarization Pr:30μC/cm2. Recovering of ferroelectric properties did not depend on annealing atmospheres.

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Electrical breakdown of Al2O3 and PZT thick films deposited using aerosol deposition method are investigated. The thickness of films were 1~10 mm. Minimum value of electrical breakdown of alumina over 2 MV/cm was and PZT over 500 kV/cm were achieved. Breakdown electrical filed of alumina increases increasing layers thickness, which is contrary to PZT films' property.

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Coating of nickel / alumina composite layer by Aerosol Deposition Method was investigated. Nickel / alumina ratio was controlled by initial amount of nickel and milling time. By X-ray diffraction patterns and STEM-EDX, microstructure of the starting materials and the composite layer was observed. Nickel phase was distributed homogeneously in alumina phase. Moreover, we discussed the effect of nickel / alumina ratio on the resistance to friction as the mechanical property of the composite layer.

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20∼30vol% SiC ink was prepared, and patterned directly by ink jet printing. The effect of the ink characteristics was studied on both printing and pattering behaviors. The pattern printing could be realized by 25vol% ink.

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Spray freeze drying (SFD) method was developed to fabricate ceramic powder granules with high homogeneity for high performance ceramics. In this study we prepared high density granules from high solid loading slurry(40&50vol%) through the SFD technique. Granules obtained through SFD were characterized with SEM , immersion liquid technique and powder tester. The ceramics prepared from the SFD granules (SL 40vol%) had the mean strength of 510MPa and the Weibull modulus m=17.5.

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Two granules types, soft and hard, were considered in this study. The compaction process of these granules was examined by the typical compaction diagram. Three stages of compaction were obtained for each granule, which represents the density changes during the formation of green compact as function of the applied pressure. Significant difference in the compaction curve was obtained for each granule type. This difference was clearly related with the internal microstructure of the resultant green compacts.

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To analyze the relationship between molecular weight of polymer dispersant and particle diameter in dense Al2O3/ethanol suspension, the macroscopic viscosity of suspension with different molecular weight of polymer dispersant was determined by viscometer. The optimum molecular weight to obtain the minimum viscosity decreased from 10000g/mol to 1800g/mol with decreasing of the particle size from several 100nm to 10nm in diameter.

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To analyze the effect of molecular structure of polymer dispersant on aggregation behavior of fine powder in SiC or TiC dense suspension, some kinds of polymer dispersant, which had different hydrophilic to hydrophobic group ratio, were synthesized from acrylic acid and stylene or methyl acrylate monomer. The optimum hydrophilic group ratio to hydrophobic group, m:n, in polymer dispersant to obtain the minimum suspension viscosity depended on the structure of hydrophobic group. For example, in the case of acrylic acid/stylene copolymer, the optimum ratio was 50:50, on the contrary, in the case of acrylic acid/methyl acrylate copolymer, the suspension viscosity decreased with increase of hydrophobic group ratio.

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Nano-particles are gathered attention in a variety of ceramic fields. Unfortunately, we have only a little knowledge of dispersion behavior of nano-particles in slurry. In order to observe dispersion state of nano-particles, in-situ solidification technique using polymerization of organic monomers was utilized. Thin section of solidified ceramic slurry was observed by transmission electron microscope. The relationship between dispersion, pH, viscosity, and zeta potential will be discussed.

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We investigated the rheological properties of the slurries prepared through the planetary mixer. The planetary mixing enhanced the fluidity of the slurry for a short time. For a long time mixing, however, a film was observed on the surface of the slurry like the Ramsden phenomena, because the temperature of the slurry elevated by planetary mixing. The slurry containing the film showed high viscosity. The slurry prepared by ball milling after planetary mixing had lower viscosity than that prepared by an only ball milling.

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