Coal fly ash (CFA) is a useful byproduct of the combustion of coal. It is composed primarily of almost perfectly spherical aluminosilicate glass particles. This spherical characteristic and other characteristics of CFA should be exploited, rather than simply using CFA as inert filler for construction. Unfortunately, the presence of carbon residues and high levels of heavy metals has so far limited the uses of CFA. Forced leaching methods have been used to improve the technical and environmentally friendly qualities of CFA, but these processes do not seem to be economically viable. Actually, CFA is a major source of Si and Al for the synthesis of industrial minerals. Potential novel uses of CFA, e.g., for the synthesis of ceramic materials, ceramic membrane filters, zeolites, and geopolymers, are reviewed in this article with the intention of exploring new areas that will expand the positive reuse of fly ash, thereby helping to reduce the environmental and economic impacts of CFA disposal.

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CaO-coated aluminosilicate foam, Cs_0.9Al_0.9Si_2.1O₆, was fabricated by utilizing a polyurethane foam, and CO₂ absorption behavior of the foam was investigated. Aluminosilicate foam was fabricated by two-step heat treatment at 873 K for 20 h and 1523 K for 5 h following the coating of aluminosilicate slurry on the polyurethane foam. CaO-coated foam was fabricated by the decomposition of Ca(OH)₂ pillar crystals prepared by coating CaO slurry on the aluminosilicate foam at 1073 K for 5 h, which resulted in the formation of porous CaO on the foam. The CaO-coated foam showed good CO₂ absorption ability and a long lifetime for the cyclic process of CO₂ absorption and desorption. The CaO-coated foam continued to maintain a CO₂ absorption ratio of approximately 90% for 15 CO₂ absorption and desorption cycles.

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This study investigates the effects of a voltage swing interval on 1,4-dioxane decomposition in aqueous media. The concentration of 1,4-dioxane decreases with the decreasing voltage swing interval, but the change is small. In contrast, the concentration of EGDF increases with the decreasing interval. Its difference is much greater than that of 1,4-dioxane. These results suggest that the diffusion constant of EGDF in a pore structure differs from that of 1,4-dioxane and that the response to the voltage swing interval depends on the chemical species. For effective water purification using this system, proper material design and optimization of operation conditions are necessary.

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CaO-Fe₂O₃-SiO₂ (CFS) compounds were prepared from mixtures of Ca(OH)₂, FeOOH and SiO₂ and their simultaneous uptake properties for cations and anions were investigated. The starting powders were mixed in various ratios using a planetary ball mill and heated at various temperatures in air and flowing N₂ atmospheres. Amorphous compounds were formed by heating up to <600°C while hematite (α-Fe₂O₃) was crystallized at ≥600°C and calcium silicates and/or calcium iron silicates at ≥800°C. Simultaneous ion uptake experiments were carried out by a batch method using solutions containing same concentrations of Ni²⁺, NH₄ ⁺ and H₂PO₄ ^-. The samples heated at 600°C showed the highest ion uptake ability. The uptake abilities were higher for Ni²⁺ and H₂PO₄ ^- than for NH₄ ⁺ and increased with increasing CaO content in the CFSs. The uptake abilities for three ions enhanced by heating the samples in flowing N₂. The simultaneous uptake mechanisms are thought to be similar to those observed in the CAS compounds, i.e. ligand change (Ca²⁺→Ni²⁺), compound precipitation and adsorption. The CFS compounds have the following advantages compared with CaO-Al₂O₃-SiO₂ (CAS); (1) higher uptake ability for phosphate ions (a model for harmful oxyanions) and (2) easy separation of a contaminated sorbent from the solution after uptake using a magnet.

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A zinc-iron layered double hydroxide (Zn-Fe LDH) with sulfate as the interlayer ainon has been prepared by the coprecipitation method. The LDH was dehydrated in three steps below 300°C and transformed to the amorphous phase. The recrystallization from the amorphous phase to ZnO (zincite), ZnFe₂O₄ (spinel) and Zn₃O(SO₄)2 occurred at approximately 450°C. Furthermore, Zn₃O(SO₄)2 decomposed into ZnO, SO₂ and O₂ above 700°C. The adsorption ability of the Zn-Fe LDH was studied for several harmful anions (phosphate, chromate, borate, fluoride, selenate and arsenate) in aqueous solution, and it showed high selectivity for phosphate, chromate and selenate ions. The Zn-Fe LDH was found to be stable over a wide pH range (pH=2-12). The adsorption ability for phosphate ions depends on the initial pH and it increases with decreasing pH.

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A facile novel approach to synthesize the hexagonal zinc oxide microtubes is demonstrated at low temperature and normal pressure under a kind of soft aqueous solution method. Hexagonal-faceted ZnO tubes with length of 1 μm, diameter of 300 nm and shells thickness of 30 nm on average were synthesized by this new simple method. The SEM results indicate that the drying temperature played an important role on the formation of hexagonal ZnO microtubes. It was interesting to find that ZnO particles exhibited different morphologies on changing the reaction temperature. The growth mechanism is briefly discussed in this paper.

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The electrophoretic deposition (EPD) technique was employed to fabricate Ketjen black/polyvinylidene fluorid (KB/PVdF) composite films on stainless steel substrates. The preparing procedure of stable suspensions for EPD and its effects on the quality and properties of the composite films were studied. The results revealed that the synthesis of composite particles with a proper KB/PVdF ratio and their homogeneous distribution in the suspensions was a prerequisite to obtain uniform green coatings. The stainless steel substrates coated with KB/PVdF composites exhibited both high electrical conductivity and good corrosion resistance, suggesting the possibility that they serve as the bipolar plates in PEM fuel cells.

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To prepare the material for cleaning up the water polluted by the toxic organic compounds with poor polarity such the endocrine disruptor chemicals, we attempted to prepare the cation-exchangeable titania-pillared clay by the hydrothermal synthesis. White powder obtained by the hydrothermal treatment of the montmorillonite with titania precursor in water still had the cation-exchangeable property. Both TEM image and XRD patterns showed that anatase-type nano-crystals (crystalline size: ca. 20 nm) were incorporated in the montmorillonite interlayer space. The organoclay having titania nano-crystals (OCT) could be prepare by intercalating the cetyltrimentylammonium cations to the montmorillonite with titania nano-crystals (CT) due to the cation-exchange reaction. The adsorption amount of bisphenol A (BPA) by the OCT from water was about 6th times larger than that by the CT, because the OCT has higher hydrophobicity than CT. From UV irradiation experiment by 300 W high-pressure Hg lamp, it was found that OCT exhibited the higher photocatalytic decomposition ability for BPA dissolved in water than both CT and titania nano-crystal powder, which was synthesized under the hydrothermal condition. Moreover, the present OCT exhibited the high durability against the continuous UV irradiation.

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Several counter measures have been carried out for mitigating heat island effect. One of those is installing on top of the roof with base materials having planted vegetation. The base materials are required good water absorption and retention which is necessary for the plant to survive. Therefore, in this study, we investigate the relationship between water absorption and water retention within the pore structures of porous ceramics. The raw materials of the ceramics were used waste resources. The structures were changed by different state foaming additive. It was found that the water absorption was dependent on open porosity and the pore size. The water retention, was reduced excessively with high porosity. Accordingly, the control of pore structure is described in details in this study.

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Bulky palladium catalyst supported on mesoporous silica MCM-41 (Pd-MCM-41) was successfully synthesized by hydrothermal hot-pressing method. In this study, the structure of the palladium species in Pd-MCM-41 bulk before and after heat-treatment process was revealed by X-ray diffraction (XRD), X-ray absorption near edge structure (XANES) and transmission electron microscopy (TEM). Also, the microstructure and mesoporous property of Pd-MCM-41 bulk was discussed. As a result, it was revealed that these dense Pd-MCM-41 bulks possessed a high surface area of over 1000 m²/g and the structure of palladium of Pd-MCM-41 bulk is almost equal to palladium (0) metal.

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A chemical recycling process using phase separation of glass was applied to a granulated blast furnace slag with high CaO content. Glasses were prepared by adding B₂O₃ to the slag in order to promote phase separation, and the glasses were heat-treated above glass transition temperature. In the subsequent acid-treatment, however, gelation due to the elution of SiO₂ phase containing CaO occurred, not obtaining high SiO₂ solids. Then, pretreatment was introduced to reduce CaO content in slag, where the raw slag was briefly washed in acid. The slag glasses prepared from the pretreated slag were commonly phase-separated by heat-treatment regardless of B₂O₃ content. After subsequent acid-treatment, colorless insoluble solids were successfully recovered. The end products consist of 70-90 mass% SiO₂, and coloring ions such as Mn, Fe and Cr were almost completely removed from the slag glasses. Reutilization as raw materials for glass is expected.

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An environmentally benign extrusion process of ceramics was investigated by adding various clay minerals as inorganic binders to provide properties such as flowability and shape-retention, which are provided by organic binders. Ceramic pastes that contain smectite show excellent extrusion behavior and those that contain swelling mica show good extrusion behavior. The swelling property of clay minerals is considered to affect their extrusion behavior predominantly. In addition, the extrusion behavior of pastes prepared by adding wet gel containing swelled smectite is better than that of pastes prepared by adding dry smectite powder. In the paste prepared by adding wet smectite gel, the smectite becomes thin platelets and disperses homogeneously, as observed by using electron microscopes. Therefore, the addition of smectite under wet gel conditions is considered to be more effective in improving the extrusion behavior.

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Large surface area (n)MnO_x-(1-n)CeO₂ (0≤n≤1) catalysts were synthesized using a hybrid organic/inorganic route and characterized by XRD, N₂ adsorption and catalytic test. The addition of aqueous ammonia to mixed solutions of cerium and manganese nitrates in the presence of CTAB (cetyltrimethyl ammonium bromide) yielded gelatinous hydrous Ce-Mn oxide/CTA composites (MnCe_CTA). As calcined MnO_x-CeO₂ (n=0.25, 450°C) exhibited a largest surface area of 223 m²/g, which is quite larger than 80 m²/g for the corresponding oxide prepared from conventional co-precipitation route (MnCe_CP). As synthesized MnO_x-CeO₂ catalysts were tested for soot oxidation by O₂. The catalytic activity of MnCe_CP was highest at n=0.25-0.5, whereas the catalytic activity of MnCe_CTA was lower and increased monotonically with an increase of the Mn content (n). The different catalytic behavior seems to be associated with the activity of surface oxygens and lower oxidation state of MnCe_CTA.

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There is no effective method to recover arsenic dissolved in aqueous media in spite of its high toxicity. The cause for this problem resides in the difficulty to form precipitates with low solubility in water under normal pressure and temperature conditions. We developed a new technology to recover arsenite ion (As^IIIO₃ ^3-) as arsenate apatite (Ca₅(AsO₄)₃(OH)) from its aqueous solution by a hydrothermal mineralization treatment. A wide range of initial concentration of arsenite ion (1-2000 mg L^-1) was found to reduce to 0.04-0.06 mg L^-1 after the treatment. The precipitate is natural minerals, Johnbaumite, which is easily reused as a raw material for the production of industrial-grade arsenic compounds.

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The present work describes the extrusion behavior of mono calcium aluminate (CaAl₂O₄; CA) paste in order to develop a new inorganic binder for extrusion. Hydration imparted significant flowability and rigidity to the CA paste. CA paste was successfully extruded using a piston-cylindrical die with low extrusion force, under optimum curing period. Furthermore, even without the addition of the organic binder, a small amount of CA acted as a suitable inorganic binder for extrusion. These good extrusion behaviors such as good flowability and rigidity of these samples were probably caused by much free space filled with water and the lubricating effect between the particles.

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Industrial asbestos waste such as asbestos cement board, sprayed crocidolite and sprayed amosite was heated in a vacuum. The detoxification conditions were then established in reference to JIS A 1481:2006 and JIS K 3850-1:2006. When asbestos cement board was heated at 700°C for 1 h, detoxification of the cement board was completed. On the other hand, in the case of amphibolic asbestos waste, such as sprayed crocidolite and sprayed amosite, was heated, a phase-contrast microscope analysis was not applicable for identification of asbestos heated at more than 500°C. According to XRD analysis, crocidolite was eliminated by heating at 800°C for 3 h. Furthermore, amosite was not detected after heating at 700°C for 3 h. Finally, the grindability of heated amphibolic asbestos was investigated. When sprayed crocidolite was heated at 900°C for 3 h and then ground with a mortar for 300 s, the crushed grains had a length of less than 5 μm and an aspect ratio of 3. In addition, when sprayed amosite was heated at 1000°C for 3 h and then ground, the crushed grains had a length of less than 5 μm and an aspect ratio of 3.

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Fe₂O₃ red pigments, especially hematite particles have been widely utilized in many technologies, such as pigments, catalysts, coatings, flocculants, cosmetics, electronic materials ad abrasives. There are many commercially available Fe₂O₃ powders for use as red pigment for Japanese porcelain enamel. However, the tone of red color of Fe₂O₃ pigments was strongly influenced by synthesized temperature. It was important that the color-stable pigments, which were not affected by morphology and dispersal behavior, were synthesized for use as thermally stable red pigments. The present work was to study the possibility of synthesizing red inorganic pigments by composite of Fe₂O₃, Al₂O₃ and SiO₂.

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Periodic patterns with submicrometer to micrometer repetitions are known to be applicable for various optical devices such as diffractive gratings and photonic crystal. In this paper, the periodic patterns of organic-inorganic hybrid materials have been fabricated by photolithography using UV and laser. The hybrid materials derived by the sol-gel method were composed of inorganic materials modified photosensitive organic groups. The photosensitive materials were irradiated periodically by UV light or multi-beam laser interference light, and periodic patterns were fabricated by removal of the unirradiated parts and rinse using the chemical solutions. The pillar sizes such as the height and the distance between neighboring pillars and kinds of the rinse liquids were controlled, resulting in the pillar patterns. Especially, new pillar patterns, in which the pillars are gathered at the top, were obtained by the capillary force between pillars during the drying of the rinse liquid. The interference light of femtosecond beams were irradiated for the TiO₂-organic hybrid materials with high refractive index, and periodic patterns with submicrometer repetitions were fabricated. The patterns were controlled by the number of the beam, and various kinds of two- or three-dimensional periodic patterns were obtained.

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Bioactive ceramics have high biological affinity that enables direct bone-bonding. However they do not have mechanical performances enough to repair bone tissue under loaded conditions. It has been revealed that most materials exhibiting bioactivity form bone-like apatite in body environment. We investigated apatite-forming ability of tantalum- and niobium-based oxide gels in simulated body environment in order to fundamentally clarify chemical structure effective for achieving bioactivity. We found that Ta-OH and Nb-OH groups on the surfaces of the oxide gels have a potential to form the apatite. On the basis of these findings, we have successfully provided tough tantalum metal with bioactivity by simple NaOH and heat treatments that form a lot of Ta-OH groups on their surfaces. We also synthesized bioactive organic-inorganic hybrids with flexibility by organic modification of inorganic chemical species with apatite-forming ability. A sequence of material design described above would produce bioactive materials with various mechanical properties.

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Ferroelectric (Y, Yb)MnO₃ thin film is one of a candidate for the application to the ferroelectric memories. This paper focused the preparation of (Y, Yb)MnO₃ thin films by chemical solution process. The synthesis of (Y, Yb)MnO₃ thin films using alkoxy-derived solutions and the effects of crystallization conditions and compositions on the crystallographic properties have been investigated in detail. On the basis of fundamental studies, we were able to find that crystallization in Ar was essential for the better electrical properties. Additionally, the ferroelectric properties of the (Y, Yb)MnO₃ thin films were investigated by measuring the electrical properties of metal/ferroelectrics/metal (MFM) and metal/ferroelectrics/insulator/semiconductor (MFIS) structures.

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The relationship between electrical properties and oxygen tracer diffusion was focused for Bi based piezoelectric ceramics including typical perovskite ferroelectrics, (Bi_1/2Na_1/2)TiO₃ (BNT), and Bi layer-structured ferroelectrics, Bi₄Ti₃O₁₂ (BIT). The oxygen tracer diffusion was investigated by secondary ion mass spectrometry, SIMS. Volume diffusion coefficients, D_v, of ¹⁸O in Bi excess BNT (BNT+Bi₂O₃ 0.3 mass%, BNT-0.3) and V-substituted BIT (Bi₄Ti_3-xV_xO₁₂, BITV-x) ceramics were dramatically decreased as compared with those in non-doped ceramics. These results suggest that the concentration of oxygen vacancies decreased. On the other hand, electromechanical coupling factor, k₃₃, for BNT-0.3 and BITV-0.02 ceramics are 0.47 and 0.25, respectively, which are the largest in each system.

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Structural control of silica-based materials prepared by sol-gel chemistry is important from both fundamental and practical viewpoints. This paper reviews our work on the synthesis of ordered siloxane-based nanomaterials by self-assembly of organosilane-based precursors. Lamellar siloxane-organic hybrids with various structures, macroscopic morphologies, and properties have been prepared from long-chain alkyltrialkoxysilanes or organoalkoxysilane-tetraalkoxysilane mixtures by self-assembly during hydrolysis and polycondensation. Furthermore, the molecular design of novel alkylsiloxane precursors having a large oligosiloxane head led to the formation of hybrid mesostructures consisting of cylindrical assemblies that gave ordered microporous or mesoporous silica by calcination. These results open a new self-assembly route to the design of ordered nanoporous materials as well as nanohybrid materials without the use of any templates or structure-directing agents.

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Carbon nanotube was synthesized in organic liquids carbon source by using La₂NiO₄ ceramics catalyst. The La₂NiO₄ ceramics particles were deposited on a Si substrate by using electrophoretic deposition. The Si substrate supporting La₂NiO₄ ceramics particles was dipped in liquied ethanol, and then DC power current was applied to the Si substrate. After this reaction process, carbon naotube was observed on the Si substrate. Next, various liquid organic compounds were applied as the carbon source for this method. All the organic compounds used in this study were effective for the synthesis of carbon material. However, the shape of the carbon material was depended on the kind of organic compound.

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This work aims at studying of an efficient way for synthesizing nano-sized particles of lead-bismuth alloy and illustrating their fabrication mechanisms from SEM morphologies. With highly ordered nano-channels developed on the surfaces of anodic aluminum oxide (AAO) template, the lead-bismuth eutectic (Pb₄₅Bi₅₅) as homogenous melt was cast inside of a sealed tube. It is deduced that the template with its nano-scale asperities works as an ultra phobic surface aids lead-bismuth droplets to be suspended and then solidify to form as nano-spheres. Disordered structure of template introduces more nucleation sites and higher latent heat. In this case, bigger sizes and irregular shapes of nano lead-bismuth are observed inside of the pitting.

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A Gd-doped ceria powder (GDC, Ce_0.8Gd_0.2O_1.9) prepared from an oxalate precursor was hot-pressed at 1173-1273 K in Ar atmosphere and annealed in air at 1273-1473 K to control the bulk density and grain size. Complex impedance of GDC of the microstructures of 0.29-5.6 μm average grain size and 95-98% theoretical density were measured at 573-1073 K in air in the frequency range from 100 Hz to 2 MHz. The bulk conductivity (σ_i(b)) was independent of the grain size and the activation energy for the migration of oxide ions was 85-88 kJ/mol. The grain boundary conductivity (σ_i(g)) was far small as compare with σ_i(b) (σ_i(g)=1/40-1/700 of σ_i(b) at 573 K). The σ_i(g) was influenced by the average grain size and showed a minimum value at around 3 μm and gradually increased with decreasing grain size. However, the total conductivity decreased for smaller grain size because of the increased thickness of grain boundary of relatively low conductivity. The information of diffusion of oxide ions from the surface into GDC inside was also reported.

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The effect of binder systems having the same glass transition temperature (T_g) on rheological behavior and properties of green sheets was investigated in this study. Four polymers were produced by changing the ratio of three monomers, n-BMA (n-Butyl Methacrylate), 2-EHMA (2-Ethyl Hexyl Methacrylate) and MAA (Methacrylic Acid). T_g of polymers were 20.2, 7.1, -2.6 and -9.9 degrees Celsius in a calculation respectively. DOP (Dioctyl Phthalate) was added to former three polymers in order to adjust T_g to -9.9°C degree Celsius by coordinating quantity of addition. These polymers were used as binders for alumina green sheets. As a result, all of the suspensions showed Newtonian Flow behavior, and the quantities of adsorbed polymer to alumina particles were almost the same. The packing degrees of green sheets were more than 58 mass%. As the quantity of DOP in binders increased, the packing degree of green sheet decreased. The tensile stress and strain of green sheets were almost the same value. Judging from thermal decomposition analysis, it was found that the temperature at 50 mass% loss of organic compounds in green sheets were lower than temperature at 50 mass% loss in polymer sheets. In four green sheets, as for the green sheet containing much quantity of DOP, maximum thermolysis speed was observed at the lowest temperature.

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We investigated crack generation and methods for preventing it in glass ceramics when Cu-glass paste and glass ceramics were co-fired. Cu-glass paste was used to fill the through holes of a glass-ceramic green sheet consisting of borosilicate glass/Al₂O₃/cordierite by screen-printing. Cracks are generated in the glass-ceramic portion that surrounds the through holes parallel to the circumference. These cracks occur when the tensile stress generated at the interface between the conductor in the through hole and the glass ceramic as a result of a mismatch in the coefficients of thermal expansion (CTEs) between Cu and glass ceramic exceeds the mechanical strength of the glass ceramic. The magnitude of the tensile stress was calculated by performing stress analysis using a model based on a thick multilayer cylinder. These cracks can be prevented by either greatly reducing the CTE of Cu conductor by adding a large amount glass or by reducing the Young's modulus of the Cu conductor and without adding additives to the Cu paste for promoting sintering (e.g., glass), which increase the density of the Cu conductor.

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Suitable types of glass for laser micromachining using a Nd:YAG laser have been developed. The composition of these types of glass is (70-x)SiO_2-xB₂O₃•10Na₂O•10CaO (x=0, 10, 15, 20, 25, 30). These types of glass contain the Co ions found in a glass matrix (adding to the mother glass). After machining with the 2nd harmonic beams of a pulsed Nd:YAG laser, the bump in the glass host, the pit at the bump in the glass host and the sole pit were all formed. This report was conducted for researching the relationship between bonding intensity of glass and thermo-mechanical properties, and for finding out the possibility of the fabrication of optical device. The maximum height of the bump in the glass was 16 μm and had a radius was 262.3 μm. We found that the Co ions acted as sensitizers in the laser machining of the glass and this process can be used for optical device fabrication process.

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The bone mechanical function depends on both bone quantity and quality corresponding dominantly to bone mineral density (BMD: density of biological apatite) and other factors, respectively. BMD is correlated with bone strength but accounts for only 60-70% of the variance in the ultimate strength of bone tissue. Thus, new parameters representing bone quality have been investigated so far. Bone has a well-organized microstructure on the nano-scale level and is composed of mineral biological apatite (BAp) and collagen (Col) fibril, providing reinforcement and pliability, respectively. Because BAp crystallizes in an anisotropic hexagonal lattice, mechanical properties of a BAp crystallite should depend on the crystal orientation. Thus, preferential orientation of the BAp c-axis along the extended collagen fibrils in hard tissues must be closely related to the mechanical function of bone and is also utilized as a possible index for evaluating bone quality. In this study, BAp orientation was analyzed as a parameter of bone quality in hard tissues under various conditions such as original, regenerated and diseased bones. Finally, we can conclude that the degree of BAp orientation is a useful parameter to evaluate in vivo stress distribution, nano-scale microstructure and the related mechanical function, the regenerative process of the regenerated bone and to diagnose bone diseases such as osteoarthritis, etc.

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Collagen and octacalcium phosphate (OCP) crystals of micrometer size with anisotropic morphology were combined under physiological temperature and pH. OCP crystals elongated in the c-axis direction were grown in a reaction chamber where diffusion was controlled by a cation selective membrane. The size of crystal used was 40-50 μm in length, about 2 μm in width and aspect ratio of around 20-25. Atelocollagen was reconstituted and cross-linked in the presence of the crystals at 37°C for 20-48 h under stirring. Despite stirring and mixing during fabrication process, the long crystals assembled with reconstituted collagen fibers and arranged more or less parallel to each other along the collagen fibers. This suggested that OCP crystals and collagen fibers assembled through some interaction, by which crystals stayed on/between collagen fibers during fabrication process. Collagen content of resultant composites was arbitrarily changeable in the range of 20-90% by weight. Thus, the composite of long OCP crystals and collagen was newly designed for future application as a bone substitute material.

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The effect of swift heavy ion irradiation on the surface modification and bioactivity of microwave sintered hydroxyapatite (HAp) pellets has been studied. The irradiated surface of the pellets was completely covered by tightly packed rectangular platy crystals. The pellets subjected to 300°C conventional sintering (after microwave sintering) before irradiation showed a plain surface. XRD studies confirmed the surface to be HAp but decrease in crystallinity and crystal size was observed. In vitro bioactivity study had revealed the formation of unique three dimensional macroporous apatite layer on irradiated surfaces. The irradiation with swift heavy oxygen ions enhanced the bioactivity of the HAp bioceramics.

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Gas reduction-nitridation (GRN), which uses a mixture of NH₃ and carbohydrate as a reactant gas, has been proposed a synthetic technique for producing high-purity nitride powders. In this study, β-SiAlON powder was produced from zeolite using GRN. Zeolite was used directly as the raw material without previous preparation or handling. It was found that high purity β-SiAlON nanopowder was synthesized at 1400°C for 60 min. Furthermore, pure β-SiAlON was successfully produced, containing no minor phases, by the optimization of nitridation, that is, of concentration of C₃H₈ and the timing of its introduction.

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An electrochemical method was established for achieving apatite formation on the surfaces of Ti and its alloys in simulated body fluid (SBF). Crystalline titania layers are formed on pure Ti, Ti-6Al-4V, Ti-6Al-2Nb-1Ta and Ti-15Mo-5Zr-3Al alloy surfaces when these alloys are anodized in H₂SO₄ solutions of different concentrations and at different applied voltages. The anodically oxidized substrates form a dense and uniform bone-like apatite layer on their surfaces in SBF that contains ions in concentrations similar to those present in human body blood plasma. The apatite formation on the surfaces of Ti and its alloys in SBF is proposed to be induced and nucleated by the lattice-matching relationship of the crystal structures between the apatite and rutile phases in the titania layers. As the surface morphology of titania layers on anodically oxidized Ti and its alloys is a three-dimensional, open, porous structure, the resultant surface structure can provide strong adhesive strength between the apatite layer and the substrates. Therefore, use of the described anodic oxidation is expected to result in Ti and its alloys being suitable for use in bioactive implant materials, even under load-bearing conditions.

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The types of solvent affected the properties of nano-sized Pb-based glass powders prepared by flame spray pyrolysis. The glass powders prepared from the alcohol-free spray solution was Pb rich in comparison with the composition of the spray solution. However, the addition of alcohol to the spray solution decreased the atomic ratio of Pb to Si components in the nano-sized glass powders. The addition of ethyl alcohol or methyl alcohol to the spray solution improved the characteristics of the inner structures and transmittances of the dielectric layers fired at a low temperature of 460°C. The transmittances of the dielectric layers formed from the nano-sized glass powders obtained from the spray solution containing alcohol were higher than 80% within the visible range at a low firing temperature of 460°C. However, the transmittances of the dielectric layers formed from the micron-sized and nano-sized glass powders had similar transmittances higher than 90% in the visible range at the firing temperature of 520°C.

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Photocatalytic machining of the organic molecular layer of octadecyl-trichlorosilane (OTS) coated on a Si wafer was investigated in the atmosphere by use of a porous TiO₂ micro wire which was prepared by phase separation and selective leaching process. The OTS coated on the Si wafer surface was clearly machined within 1 min under UV irradiation. From the examination of the effect of humidity on the OTS machining rate, the ambient air was found to have sufficient condition for this machining procedure. On the contrary, the OTS in UV non-irradiated area was not machined at all. This indicated “double excitation mechanism”, which the photo induced oxygen radicals on TiO₂ were further photo excited by the irradiation of UV light, proceeded. This process is capable of on-demand machining of organic molecular layer in normal atmospheric condition.

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To fabricate the energy storage ceramics with large sizes for pulsed power transmission line, the densification behavior and dielectric properties of Ba_0.3Sr_0.7TiO₃ with 0-8 mass% BaO-Al₂O₃-B₂O₃-SiO₂ glass additive were investigated. With increasing glass content, both the densification temperature and densification rate decreased remarkably. The shrinkage rate mismatch caused by green density gradient also reduced remarkably, which contributed to the fabrication of large sizes of ceramic with dense microstructure. The additions of glass phase decrease the dielectric constant. However, the breakdown strength of the samples can be increased by a factor of 1.5 over the pure BST because of the modification of the microstructure. For the samples containing 4 mass% glass additions, optimal dielectric properties were obtained: dielectric constant is 440, dielectric loss is 3.5×10^-3 at 1 MHz, and breakdown strength is 16.4 kV/mm.

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Frequency dependences of the dielectric constant (ε_r′) were investigated for the perovskite-type oxide BaCe_0.9Y_0.1O_3-δ, which is a typical proton conductor. Numerical calculation of the frequency dependence of ε_r′ clarified that the large ε_r′ originated from the superimposition of both electrolyte-electrode interfacial and Debye-type polarizations. The Debye-type polarizations which originated from the dopant-vacancy associates, (Y_Ce′-V_O^••)^• were depressed under wet Ar atmosphere. Therefore, it can be speculated that the proton may occur according to the following equilibrium equation: H₂O+V_O^••⇔2H^•+O_O^×.

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Boron nitride (BN) with flake-like morphology has been synthesized by reacting powder H₃BO₃, Mg and NH₄Cl in an autoclave at 600°C for 10 h. X-ray diffraction (XRD) patterns show the sample has a hexagonal phase with lattice parameters a=0.2506 and c=0.6692 nm. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) indicate the as-synthesized product is mainly pure flakes with a mean size of about 100 nm in width and 600 nm in length. X-ray photoelectron spectra (XPS) give an average B/N atomic ratio of 0.98:1. Fourier transformation infrared spectroscopy (FTIR) has a strong B-N absorption at 1376 cm^-1 and 814 cm^-1.

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A blue afterglow was observed in the bazirite-type BaZrSi₃O₉ synthesized by a solid-state reaction for the first time. The synthetic bazirite phase showed a clear blue long-lasting luminescence at room temperature after the exposure of UV light, in spite of the free from any lanthanide-doping. It was proposed that the afterglow in the BaZrSi₃O₉ phase was originated from the occupation of Ti⁴⁺ as an impurity in the distorted octahedral site.

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