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Sintered pellets of 3 mol% yttria-stabilized zirconia (YSZ) were electrically polarized by dc voltages in 2 to 1000 V (20 – 10 kV/cm). After hydrothermal treatment at 120 ˚C for 24 hours, the crystal structures of surfaces of polarized pellets were characterized using XRD measurement. The results indicated surfaces of samples were transformed to monoclinic phase. The amounts of monoclinic phase were decreased with increasing the applied voltage. In addition, the amounts varied with the polar of surfaces.

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Solid-state protonics is a new reseach field attracting much current attention. One of the most urgent subjects in this field is to create a novel proton conductor, from the viewpoint of developing new energy and energy conservation technologies, including photovoltaic, hydrogen storage and fuel cell technologies. In this work, we report on a proton-conductive organic-inorganic hybrid system, which is a coordination polymer. Such a metal-dimer system with multi-redox property has a large potentiality for the creation of new-functional and high-performance materials in metal-complex solids. New highly proton-conductive coordination materials, conductive mixed-valent nanotube-MOF and highly-concentrated hydrogen-storage nano-materials are presented.

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Molluscan shells, which are typical examples of such biominerals, are composed of mainly inorganic calcium carbonate crystals and less amounts of organic matter. The organic matter forms matrices, such as sheaths, envelopes, walls and sheets, to regulate the polymorph, orientation, shape, and texture of the crystals. Besides, calcium carbonate crystals in shells contain a certain amount of intracrystalline organic macromolecules such as proteins and polysaccharides. The size of the molecules is several nanometers which can be visualized as Fresnel or Z contrasts by TEM/STEM imaging. From the distribution of the molecules in the crystals, it is inferred that the multi-layer structure of the larval shell and mosaic structure of the columnar layer in bivalve shells are constructed by non-uniform incorporation of such macromolecules.

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Control of scattering is one of factor for improvement of properties of phosphor. We synthesized nanocrystal phosphor particles by chemical solution methods such as precipitation from homogeneous solution. YBO3:Tb type nanophosphor particles which emit green light by UV excitation and can be dispersed in water were obtained by precipitation from homogeneous solution using hexamethylenetetramine as an precipitation agent.

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Phase- and morphology-control of TiO2 was performed by a facile hydrothermal method using a novel water-soluble titanium-picolinato complex as a precursor. Single-phase rutile or brookite type titania can be obtained by tailoring the pH of the complex solution. Rutile with a hierarchical microstructure was synthesized using an excess amount of ligand as an additive and the final product consisted of microspheres with mesopores formed by a self-assembly of nanorods. The anisotropic growth of nanorods with a high aspect ratio was explained by a capping mechanism.

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A Ba0.5(Bi0.5K0.5)0.5TiO3 (BBKT) plate-like particle is synthesized by a novel two-step solvothermal soft chemical process. In the first step plate-like particles of a layered titanate H1.07Ti1.73O4 (HTO) precursor is solvothermally treated in Ba(OH)2 solution to obtain plate-like particles of a BaTiO3-HTO (BT-HTO) nanocomposite. In the second step the nanocomposite particles are hydrothermally treated in BiCl3-KOH solution to obtain the BBKT plate-like particles.

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Bismuth layer-structured ferroelectric ceramic films on glass substrates were prepared by an aerosol deposition method, and their structural analysis were performed.

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Non-oxide ceramic materials like titanium nitride (TiN) and titanium boride (TiB₂) have become a promising candidate for advanced structural materials due to theirs excellent mechanical strength and chemical stability at elevated temperature. This work attempts to study the sintering of TiN-TiB₂ composite by spark plasma sintering (SPS); the arc melting was also performed to investigate the morphology of specimen. The mixing powders of various compositions were densified at 2173-2573 K under the pressure of 10 MPa for 60-300 s. The density over 99%TD was achieved for composite with the TiB₂ content of 20-40vol% sintered at 2573 K under the pressure of 10 MPa for 60 s. While the TiN-TiB₂ prepared by SPS showed the core-shell structure, the composite obtained by arc melting had the eutectic structure.

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For the development of tungsten substitute materials for cemented carbide (WC-Co), new titanium carbonitride (Ti(C,N)) base cermets are studied and developed to applied cutting tools and wear resistant tools. New carbonitride solid solution , (Ti,Me)(C,N) [Me: metal element] as hard material in cermets is needed to improve the properties of cermets. The material properties of (Ti,Me)(C,N) [Me=Mo,W] ceramics were investigated.

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Refractories for iron and steel making are chemically damaged by contact with high temperature molten metal or slag, and mechanically by thermal shock of the severe temperature changes. The damage mechanisms are complex because using conditions change with the manufacturing process and the using parts. In order to prevent an accident such as a metal or slag leak and decrease the refractories costs, it is important to clarify the damage mechanism and take measures. In this paper, the author will present the practical cases, which are main trough material, castable for steel ladle, castable for tundish and others.

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Pressureless sintering of a submicron B4C powder doped with various amounts of Al2O3 and Y2O3 additives were carried out. It was found that the consolidation virtually proceeded via a liquid-phase-sintering mechanism. Effects of composition and amount of sintering additives and sintering temperature on the densification and grain growth behaviors were studied through monitoring density changes and microstructural evolution. Some properties such as elastic modulus, hardness and fracture toughness were characterized.

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The microwave dielectric properties of Nd(1-2x/3)Bax(Mg0.5Sn0.5)O3 ceramics were examined with a view to their exploitation for mobile communication. The Nd(1-2x/3)Bax(Mg0.5Sn0.5)O3 ceramics were prepared by the conventional solid-state method with various sintering temperatures. The X-ray diffraction peaks of the Nd(1-2x/3)Bax(Mg0.5Sn0.5)O3 ceramics shifted to lower angles as x increased from 0 to 0.05. The X-ray diffraction patterns of the Nd2.94/3Ba0.03(Mg0.5Sn0.5)O3 ceramics revealed no significant variation of phase with sintering temperatures. A density of 6.89 g/cm3, a dielectric constant ( ) of 19.1 and a quality factor (Q f) of 212,100 GHz and a temperature coefficient of resonant frequency of -68 ppm/OC were obtained for Nd2.94/3Ba0.03(Mg0.5Sn0.5)O3 ceramics that were sintered at 1550 OC for 4 h.

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