The polymerizable complex (PC) method was developed to prepare copper-based high-T_c superconducting oxides with improved superconducting properties, phosphor materials with excellent emission intensities and water-splitting photocatalysts with higher activities. The PC method is based on the formation of metal complexes and subsequent polyesterification between a hydroxy-caroboxylic acid such as citric acid and a glycol such as propylene glycol, so that homogeneity of the metal species inside the polyester resin precursor is maintained on the molecular scale. An example of Y₂SiO₅:Ce³⁺,Tb³⁺ co-activated phosphor synthesis utilizing a new water soluble silicon compound is provided. The PC method is also an efficient methodology for the preparation of promising compounds for testing, without the requirement of tailoring the synthesis for each candidate; a scheme to search for the potential Tm³⁺ activated phosphors in the series of complex gallates as hosts has been demonstrated as a representative example.

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Microstructure developments under fluorine plasma have been investigated in the Al₂O₃ ceramics containing artificial pores with controlled purity. The erosion behaviors by fluorine plasma consisted of a uniform erosion throughout the specimen surface and local erosions around the artificial pores and defects such as intrinsic irregular pores and damages formed during the grinding and polishing steps. The effects of the pores on the microstructure development were more distinct in the low purity Al₂O₃ specimen. The erosions around the pores, in the beginning, showed polygonal or flower-like microstructures in high or low purity Al₂O₃, respectively, indicating a weak grain boundary of glassy phase under the fluorine plasma. The extended plasma treatment resulted in loose structures around the pores in the low purity specimen, possibly producing contamination particles. In contrast to the polycrystalline Al₂O₃, single crystalline Al₂O₃ showed only uniform erosion. Although the microstructure developments were completely different depending on purity, porosity and polycrystallinity, etch depths did not appear so different, implying that the etch depths might not properly represent the plasma resistance of the materials.

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To understand the controlling factor of film thickness in aerosol deposition method (ADM), the deposition apparatus was improved at first and the effect of pretreatment of raw barium titanate powder was studied. A developed aerosol generator where the carrier gas was separated from the aerosol generating gas was effective to avoid the agglomeration of powders during the deposition. Two dimensional scanning of the substrate decreased the film-thickness distribution caused by the imhomogeneity of deposition rate in a line-type nozzle. Effect of pretreatments of raw powders, including sieving, drying, planetary ball milling and heating was examined, respectively. There was an optimum rotational velocity of planetary milling to increase the film thickness, indicating that adequate agglomeration of raw powders enhance the film deposition. The film thickness decreased as the heating temperature increased. The heating strengthened the agglomeration of raw powders which restricted the film deposition because the kinetic energy of particles in the aerosol was consumed to break the agglomerations rather than making film. Weakly agglomerated powders with optimum size enhanced the film thickness in ADM.

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A silica-polymer composite with oriented macropores was fabricated from tetraethoxysilane (TEOS) incorporated with poly(ethylene glycol) (PEG) via a sol-gel method. The solution mixture containing PEG and TEOS after hydrolysis was subjected to shear stress so that the macroporous structure generated by spinodal decomposition during the process of polycondensation to a silica-PEG-rich phase and a solvent-rich phase was elongated and oriented toward the shear flow direction. It was found that shear flow is effective for macropore elongation after the solution mixture becomes turbid. The optimum PEG content for macropore elongation was also revealed. The elongation ratio of the macropores was dependent to a certain extent on the shear rate.

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ZnO nano-/micro-crystals with tubular morphology were synthesized by a simple oxidation of a source material mixed with Al, Zn, and Au in air at atmospheric pressure. The tubular morphology was formed when Au was contained in source material. Thus, it was found that Au played an important role in the formation of the tubular morphology. The ZnO crystals with tubular morphology had wurtzite structure and were grown along the [0001] direction. It is proposed that the tubular morphology is formed by the nucleation and the coalescence of nanorods at the six corners of hexagonal base rod.

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Magnetite (Fe₃O₄) particles with various shapes have been synthesized through a simple hydrothermal reaction. The experimental results reveal that the control of the morphology and size of magnetite particles could be realized by adjusting reaction parameters. The diamond-like and prism-shuttle-like magnetite particles with micro-size are obtained by using Fe₃O(OCOCH₃)₆NO₃ and FeCl₂·4H₂O as iron sources. The rod-like and spherical magnetite particles with nano-size are obtained by using Fe₃O(OCOCH₃)₆NO₃ and FeSO₄·7H₂O as iron sources. Ethylenediamine and hydrazine are used as organic bases. The particle size changed from micro-size to nano-size when FeSO₄·7H₂O was used as the starting material instead of FeCl₂·4H₂O. The growth mechanism of magnetite particles also is discussed. The magnetic properties of all magnetite particles exhibit ferromagnetic behavior according to the magnetic hysteresis curve measured at 5 K.

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In order to improve the electrical properties of stabilized Bi₂O₃ such as oxide-ion conductivity, conductivity degradation by annealing and reduction resistivity, the solid solution systems, (Bi_0.8-xLn_xEr_0.2)₂O₃ (0.0 ≦ x ≦ 0.20) (Ln = La, Pr, Nd) were investigated. Though the electrical conductivity of the three solid-solution systems decreased with increasing x, the La-doped system showed the highest conductivity among these systems. In the (Bi_0.8-xLa_xEr_0.2)₂O₃ system, (Bi₀₇La_0.1Er_0.2)₂O₃ showed the best electrical properties, i.e., the high oxide-ion conductivity, the small degradation by aging and the high resistivity for reduction down to ∼10^-14 Pa of oxygen partial pressure.

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A new ferroelectric solid solution of (0.90-x)BiScO₃-xPbTiO₃-0.10Pb(Mn_1/3Ta_2/3)O₃ (BS-PT-PMT, x = 0.54-0.70) has been synthesized in the form of ceramics by solid-state sintering and characterized by means of X-ray diffraction, ferroelectric and piezoelectric measurement. All ceramics with different compositions crystallize in the pure perovskite phase. With increasing PT content, a morphotropic phase boundary (MPB) is established at x ≈ 0.58 by X-ray analysis. The dielectric, ferroelectric, and piezoelectric characterization of the compositions near MPB were discussed.

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The relationship between microstructure and electrical conductivity of porous (La_0.8Sr_0.2)_0.99MnO₃ (LSM) ceramics were investigated. The porous LSM ceramics were prepared by sintering the cylindrically-extruded compacts at 1573 K for 6 h. The bulk density and porosity of LSM ceramics were measured by Archimedes technique. The electrical conductivities were measured using 4-probe DC technique as functions of temperature and bulk density. The open porosity was approximately proportional to the amount of binder in the LSM/water/binder mixture. The electrical conductivity decreased with decreasing bulk density, and the amount of decrease was more than predicted by the open porosity. This was related to the tortuosity of the carrier path.

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A three-layer stacked piezoelectric device with a thickness of 300 μm (100 μm per layer) was successfully prepared by aerosol deposition (AD) using a novel detachment method. Prior to preparing stacked Pb(Zr,Ti)O₃ (PZT), a gas generation layer (GGL) with specific carbon content and a dummy metal layer (DML) were sequentially prepared on a stainless-steel substrate. PZT layers and internal electrode layers were then alternately stacked by AD and sputtering, respectively. After that, the layer system was subjected to detachment annealing, where CO₂ gas was generated from the GGL and diffused along the interface between the GGL and DML, allowing stacked PZT to be detached from the substrate easily and reliably. The obtained three-layer stacked PZT exhibited an almost equivalent piezoelectric property as compared to a conventionally processed piezoelectric device.

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β-tricalcium bis(orthophosphate) [Ca₃(PO₄)₂] (β-TCP) was mechanochemically treated with a mortar grinder in three different atmospheres of air, wet N₂, and wet CO₂. H₂O and CO₃^2- were incorporated into ground β-TCP, the amount of which depended on both the grinding time and the atmosphere. As the grinding time of β-TCP increased, it hydrolyzed easily to Ca-deficient hydroxyapatite. The apatite-formation ratio for β-TCP ground in wet CO₂ was remarkably lower than that for β-TCP ground in air or wet N₂. The role of H₂O and CO₃^2- in the hydrolysis of ground β-TCP was investigated by calorimetry together with spectroscopy. In calorimetry for each ground β-TCP, a strong exothermic band was observed, which was followed by a broad exothermic band. It is considered that the first band corresponds to the process of adsorption of H₂O in the solvent onto the fresh surface of ground β-TCP and the second broad band corresponds to the apatite-formation process. With increasing amount of H₂O incorporated into ground β-TCP, both the heat evolution of the first exothermic band and the apatite-formation ratio increased linearly. The H₂O incorporated into ground β-TCP promotes the dissolution of β-TCP and apatite formation. In terms of the effect of the incorporated CO₃^2- on hydrolysis, the incorporated CO₃^2- prevents not only apatite formation but also the dissolution of β-TCP.

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High ionic conductivity of lithium in Li_xLa_(2-x)/3TiO₃ with A-site deficient type perovskite structure has attracted considerable attention owing to both the range of practical usage (e.g., all-ceramics Li secondary batteries) and the fundamental fascination of fast lithium ion transport in crystalline solids. In present paper, we investigated the arrangement of La and vacancies in La_2/3TiO₃ by means of first-principles computations combined with cluster expansion approach, since it has caused a difficulty of atomistic level discussion due to numerous freedoms of configuration. The computational results predicted the alternate La concentrated and diluted layers stacking along c-axis, which agreed with the previous structural analyses. In addition, La cluster formation within ab plane is indicated. Using predicted La/vacancy arrangement, we demonstrated to calculate the Li migration path and energy profiles during Li jump by nudged elastic band method, which showed diagonal pathways to avoid passing A-site center.

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We investigated the effects of particle concentration and an additive amount of a dispersant on the adsorption behavior of dispersant. Ammonium polycarboxylate, one of the typical polyelectrolyte was used as a dispersant in this study. Alumina slurries were prepared by changing the concentrations of both the particle and dispersant and kept in a test tube for at least 2 d. After that, the adsorbed dispersant amount was calculated from the residual dispersant concentration measured by a total organic carbon analyzer. It was found that the adsorbed dispersant amount strongly depends on the additive dispersant amount on the basis of the unit mass of particles in the slurry regardless of the particle concentration. It was also shown that polycarboxylic acid strongly absorbs onto an alumina surface and can not be desorbed by dilution, suggesting that its adsorption behavior differs from physical adsorption.

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Nano-sized SnO₂ powders with uniform morphology and narrow size distribution were prepared by spray pyrolysis from the spray solution with citric acid and ethylene glycol. The precursor powders with hollow and thin wall structure turned to nano-sized SnO₂ powders with regular morphology after post-treatment process. The mean sizes of the SnO₂ powders were changed from 56 and 350 nm when the post-treatment temperatures were changed from 600 and 1200°C. The initial charge capacities of the SnO₂ powders were changed from 224 to 443 mAh/g when the post-treatment temperatures were changed from 600 to 1200°C. The SnO₂ powders had the maximum charge capacity at a post-treatment temperature of 800°C.

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A novel electroplating technique is proposed using simple and non-toxic aqueous solutions in contrast with conventional plating baths. The metal plating process consists of a two-step procedure, i.e., combination of well-known electrophoretic deposition (EPD) and electrochemical reduction. Initially, the EPD of metal oxide particles dispersed in pure water is performed so that an oxide layer can be formed on the electrode surface. The coating layer is then electrochemically reduced to the metallic state in a neutral electrolyte solution. Dissolution-precipitation of the oxide in the second step plays an important role in densification of the resultant metal film. This communication briefly discusses the electroplating mechanism and the effectiveness of the proposed technique.

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