The porous ceramic substrate mainly consists of Si₃N₄ that repels Si melt was prepared. Porous structure with pores in micron-order was prepared by thermal decomposition of polymethylmethacrylate spherical micro-particles of 2–10 µm in diameter. The contact angle between Si melt and the porous substrate is a maximum of 160° measured by high temperature in-situ observation. For the application, spherical Si crystals were successfully prepared on the porous substrate and the repetitive preparation of spherical Si on the same substrate confirmed that the porous substrate prevents the infiltration of Si melt and is continuously reusable for crystal growth of Si.

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LiCoO₂ films were prepared on polycrystalline Al₂O₃ substrates by metal organic chemical vapor deposition (MOCVD), and the effect of the Li to Co source vapor ratio (R_Li/Co) and substrate temperature (T_sub) on the phases, orientation, morphology, and deposition rates were investigated. At R_Li/Co > 2.0, Li₂CO₃, Li_xCo_1−xO, and a LiCoO₂–CoO solid solution were co-deposited with LiCoO₂, whereas Co₃O₄ was co-deposited with LiCoO₂ at R_Li/Co < 0.7. Single-phase LiCoO₂ films were obtained in the R_Li/Co range of 0.7–2.0 at T_sub > 873 K. Rutherford backscattering spectrometry revealed that single-phase LiCoO₂ film had uniform and stoichiometric composition. The orientation of single-phase LiCoO₂ films changed from (003) to (104) and (012) with increasing T_sub at R_Li/Co ~ 1.0. LiCoO₂ film co-deposited with Co₃O₄ at R_Li/Co = 0.4 showed significant (101) orientation. The (003)-oriented LiCoO₂ had a flat surface with hexagonal faceted texture, whereas the (101)- and (104)-oriented LiCoO₂ had platelet grains in which the plate faces were tilted relative to the substrate surface. The highest deposition rate of single-phase LiCoO₂ film was 10–20 µm h⁻¹, which was 100 times greater than that reported in the literature.

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Anisotropic shrinkage during sintering was examined in c-axis oriented strontium barium niobate ceramics (Sr_0.6Ba_0.4Nb₂O₆, SBN60), which were prepared by colloidal processing in a high magnetic field. C-axis oriented SBN60 powder compact showed a large degree of shrinkage along the c-axis, which was the long axis of the primary particles. This anisotropic shrinkage of SBN60 is governed more by neck growth and grain growth during the middle or final stage of sintering than by the much number of the necking among particles during the initial stage as exhibited in c-axis oriented alumina. In tests, SBN60 grains grew anisotropically to the c-axis and showed large degree of sintering shrinkage.

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The layer-structured thermoelectric material, Al-doped (ZnO)₅In₂O₃, was fabricated by microwave irradiation within a short time of 15 min and its thermoelectric properties were examined. When comparing specimens sintered by microwave irradiation (15 min) with those by conventional heating (4 h), their microstructure and composition were similar. However, electrical conductivity was improved by microwave irradiation. Moreover, in (Zn_1−xAl_xO)₅In₂O₃ (x = 0.016, 0.032), Al-doping contributed to an increase in both the electrical conductivity and the absolute value of Seebeck coefficient, which contributed fairly to the high dimensionless figure of merit, ZT. Larger ZT was achieved by improvement in electrical conductivity by microwave irradiation and increases in both the electrical conductivity and the absolute value of Seebeck coefficient by Al doping. (Zn_0.984Al_0.016O)₅In₂O₃ sintered by microwave irradiation had the highest ZT, which was 1.5 times higher than that of (ZnO)₅In₂O₃ sintered by conventional heating at 773 K.

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Development of non toxic magnetic beads has been strongly desired to cure more effectively for patients having diseases such as cancer and osteosarcoma. In this study, Fe was added during calcium phosphate preparation by conventional wet process, and the condition of Fe ion and the effect of Fe doping on the crystal phase, microstructure and other properties of HAp were investigated. The crystal phase of obtained samples had a HAp structure with low crystallinity, and the crystallinity of samples decreased with increasing the Fe ratio. The obtained powders had granular crystals with 10 nm in diameter. From the XRD and XANES measurement, it is thought that the actual doped amount into the HAp structure was 1, 1.8 and 3 mol % for Ca of HAp in the case of 5, 10 and 20 mol % of addition, respectively, and the most of added Fe existed as an iron oxide phase at the surface of HAp particles.

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Diatomite wet foams were stabilized by diatomite particles that were rendered partially hydrophobic by hexylamine, dried, and then sintered. The particle-stabilized diatomite foam contained primary pores with a size of 50 to 200 µm, formed by particles irreversibly adsorbed at liquid–gas interfaces, and secondary pores with a size of about 3 µm, induced by both its irregular particle shapes and inherent pores. In this study, we described a method of preparing diatomite foam with a bimodal pore structure and investigated pore characteristics of the diatomite foam by scanning electron micrographs, mercury porosimetry, and capillary flow porosimetry.

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The effects of microwave sintering on the sintering behaviour, microstructure and piezoelectric properties of ZnO-doped (Bi_0.5Na_0.5)TiO₃ (ZnO:NBT) ceramics were investigated. The microstructure and piezoelectric properties of a lead-free NBT ceramic were also studied given different amounts of ZnO doping. X-ray diffraction shows that Zn²⁺ diffuses into the lattice of (Bi_0.5Na_0.5)TiO₃ to form a solid solution with a pure perovskite structure. Microwave heating with sintering temperatures below 1000°C significantly improves the densification of ZnO:NBT ceramics. The piezoelectric coefficient d₃₃ for the 0.5 wt % ZnO:NBT ceramics, sintered at 950°C, was found to be 108 pC/N, with a electromechanical coupling factor kp = 0.17.

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This paper is concerned with the synthesis, characterization, and electrochemical properties of all solid state dye-sensitized solar cells (SSDSSCs) with a dense TiO₂ layer. The dense TiO₂ layer, which was prepared from titanium hydroxide and titanium tetra isopropoxide precursor, has been characterized by X-ray diffraction, scanning electron microscopy. The experimental results showed that the TiO₂ layer formed using titanium hydroxide precursor with a thickness of about 100 nm was composed of crack free anatase-phase. The dense TiO₂ layer is found to improve the short circuit current density (Jsc), leading to enhancement in the conversion efficiency (η) of the SSDSSCs from 2.92 to 3.60%.

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The Cu-doped LiFePO₄ with/without carbon coating was synthesized by sol–gel method. The material was characterized by X-ray diffraction, Raman spectroscopy, Scanning Electron Microscopy, Energy Dispersive Spectroscopy and its electrochemical properties were investigated by charge–discharge tests. For the carbon coated sample presents a high uniformity and a particle size around 50–100 nm. Electrochemical tests show that the specified capacity was 102 mAh/g measured 0.25 C (1.5 mA) regime discharge rate, voltage range (2.5–3.7 V). Optimization of this composite would be required, but the Cu doping and carbon coating to LiFePO₄ showed a promising material for use as cathode material in lithium ion battery.

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The crystalline phase and thermoelectric properties of sintered Ca₃Co₄O₉/Ca₃Co₂O₆ mixtures prepared by a two-step heat treatment were investigated. Crystal phase and surface morphology were investigated at each step of the heat treatment. The thermoelectric properties of the material and the mixture ratio of Ca₃Co₄O₉ to Ca₃Co₂O₆, as calculated from XRD data, were strongly influenced by the compositional ratio of Co to Ca in the starting material. As the compositional ratio of Co to Ca was increased, the magnitude of the power factor increased and the slope of the power factor decreased with respect to the temperature.

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AlN powders were simultaneously sintered and bonded to isotropic graphite disks at temperatures of 1800 and 1900°C under 30 MPa by spark plasma sintering (SPS). The effects of temperature and Y₂O₃ additive content on the bonding strength were investigated. The bonding mechanism is proposed as follows: as the temperature increases, a molten Al–Y–O phase forms and flows into the open pores of graphite. As the material cools, a Al₂Y₄O₉ phase forms, resulting in a physical bond between the graphite and AlN. The bonding strength of AlN/graphite increased with an increase of temperature and Y₂O₃ content. When 10 mass % Y₂O₃ was used as a sintering additive, the bonding strength of AlN/graphite reached 19 MPa at 1900°C.

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We examined how the composition ratio of P₂O₅ to TeO₂ affected the physical properties and the structure of the semiconductive vanadate glasses in a low-melting V₂O₅–P₂O₅–TeO₂ glass system containing 57 mol % V₂O₅. It was found that increasing the P₂O₅ content and correspondingly decreasing the TeO₂ content raised the glass transition temperature and the deformation temperature as well as the fraction of the reduced V ions ([V⁴⁺]/[V_total]) and the average interionic distance of the V ions. In addition, the increase in P₂O₅ content from 7 to 32 mol % lowered the thermal expansion coefficient, volume resistivity, and density by 27, 42, and 14%, respectively, and also lowered the apparent molar volume of O ions and crystallization tendency. Furthermore, the infrared (IR) spectra suggested that the TeO₂-enriched glasses had a layered structure similar to crystalline V₂O₅, whereas the P₂O₅-enriched glasses had a denser layered structure as a result of the increased packing density of the O ions due to the reduction of the V ions.

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The morphology and spatial distribution state of CaF₂ nanocrystals in oxyfluoride glass-ceramics based on the ErF₃–CaF₂–Al₂O₃–SiO₂ system with different ErF₃ contents of 1–3 mol % and the addition of AlN were examined from transmission electron microscope (TEM) observations. The content of 3 mol % ErF₃ induced the growth of CaF₂ nanocrystals with star-like morphologies and their assemblies with the size of ~70 nm. The addition of a small amount (2 mol %) of AlN has a remarkable effect on the spatial uniform distribution (i.e., disappearance of assembly) of CaF₂ nanocrystals. The present study proposes a new method for the design of composition in rare-earth doped oxyfluoride glass-ceramics.

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The reaction mechanism for the ammonolysis of β-gallium oxide (β-Ga₂O₃) to gallium nitride (GaN) was elucidated by observing the morphology of microsized β-Ga₂O₃ single crystals with a distinct shape under a flow of ammonia (NH₃) and hydrogen (H₂) at elevated temperatures. The morphology of the microsized β-Ga₂O₃ single crystals grown on the c-plane sapphire by the thermal annealing of gallium sulfide, was not retained after calcination under a flow of NH₃ and H₂. These microstructural observations strongly support that the ammonolysis of β-Ga₂O₃ to GaN proceeds through gaseous Ga₂O, and that the rate of the reduction of β-Ga₂O₃ to Ga₂O is slower than that of the nitridation of Ga₂O to GaN.

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Activated carbons were fabricated from carbonized rice husks (CRH) by the alkaline activation with KOH and K₂CO₃. The pore structure and stored hydrogen contents of activated carbons were investigated. The specific surface area of K₂CO₃ and KOH activated samples were 1177, 1247 m²/g, respectively. The meso-pore volume of K₂CO₃ activated sample was larger than KOH activated. On the other hands, the micro-pore volume of KOH activated sample was larger than K₂CO₃ activated. These results indicated that meso-pore was preferentially developed by K₂CO₃ activation and micro-pore was preferentially developed by KOH activation. The maximum storage hydrogen contents of activated carbon by KOH and K₂CO₃ were 0.57 and 0.43 wt %, at 298 K and about 10 MPa, respectively. Thus, it suggests that micro-pore influence on stored hydrogen contents is greater than meso-pore. Consequently, for the fabrication of activated carbon which is utilized for hydrogen storage, KOH is an effective activation agent more than K₂CO₃.

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Influence of the atomic-scale surface morphology of sapphire substrates on the epitaxial growth and crystallinity of Al₂O₃ thin films was investigated by pulsed laser deposition (PLD) toward sapphire substrate engineering. Homoepitaxial growth of α-Al₂O₃ thin films on R-plane sapphire (0112) substrates with 0.35-nm-high atomic steps and approximately 20-nm-wide terraces was achieved at room-temperature (approximately 20°C) by PLD. Epitaxial growth of the α-Al₂O₃ thin films was confirmed by in situ reflection high-energy electron diffraction (RHEED). The obtained epitaxial film surface was atomically stepped similar to the sapphire substrate before deposition.

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