The press process of molybdenum is done without using an organic binder when the molybdenum is manufactured at high temperature used in powder metallurgy. The decrease in the molybdenum ingot density, which was a factor in the yield decrease of the molybdenum product, is occurred because of remaining moisture and the presence of molybdenum oxide in molybdenum metal powder. To clarify the cause of the yield decrease, the uniform distribution process of the rare earth salt by wet doping into molybdenum and the molybdenum elution to water were examined. The dopants provide a unique effect on the thermal-deformation resistance of molybdenum. In solvents of purified water and tap water, the amount of elution of molybdenum was examined as dependence on molybdenum particle sizes and the temperatures of the solvent. Moreover, elution results obtained using alkali and acid water solvents were compared. As a result, it can be suggested that a steady dope manufacturing condition can be obtained by using the metallic molybdenum or MoO₂ as the raw powder, as well as by the use of purified water held at a low temperature.

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Biominerals such as bones, teeth, the nacre of shells, and spicules of sea urchins are organic-inorganic hybrids. They have highly controlled hierarchical and complex structures. The formation processes of these biominerals are controlled by macromolecular templates of proteins, peptides, and polysaccharides in mild conditions. Biominerals have attracted much attention, because materials scientists can obtain the idea from their hierarchical structures, properties, and formation processes for use in creating synthetic, and biomimetic materials. This review highlights our recent approaches on bioinspired syntheses for the development of organic/CaCO₃ hybrids using macromolecular templates. The cooperative interactions between soluble acidic polymers and insoluble matrices have affected the CaCO₃ crystallization. Their polymorph, orientation, and complex structures can be tuned by the conditions. These materials have great potentials for new functional materials.

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Thermal poling is a process that a high voltage, or a strong electric field, is applied to a dielectric material at an elevated temperature. For glass materials, this technique has been mainly utilized to induce optical second-order nonlinearity in glass, which is a prototype of an optically isotropic material and has been believed not to show the second-order nonlinearity because of its macroscopic structure possessing inversion symmetry. On the other hand, ion implantation can be achieved during the thermal poling of glass if a dielectric material bearing ions with high mobility such as alkali metal ions is inserted in between an electrode and the glass material to be poled. In such a situation, the mobile ions can move into the glass from the dielectric material, and the glass structure is modified by the incoming ions, leading to a change in properties of the glass. In this review article, we describe about optical functions induced in tellurite glasses by the thermal poling/ion implantation technique. The optical functions are second-harmonic generation and surface plasmon enhanced birefringence, both of which are attained by the thermal poling/ion implantation process.

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Although chemical and physical synthetic routes to noble metal nanoparticles have been extensively developed, another possibility is biological synthesis by reduction of noble metal ions using microorganism. We focused on the Fe(III)-reducing bacteria Shewanella algae and Shewanella oneidensis as a candidate microbe for rapid reductive deposition of noble metal at room temperature, because the reduction potential of Fe(III) ions is almost equal to that of noble metal ions. Intracellular synthesis of noble metal (Au, Pd, Pt) nanoparticles was achieved at room temperature using resting cells of the Fe(III)-reducing bacteria, when either formate or lactate was provided as the electron donor. The bioreductive deposition of noble metal was a fast process: 1-10 mol/m³ aqueous Pd(II) ions were completely reduced to crystalline Pd(0) nanoparticles within 60 min. Biogenic metal nanoparticles 5-10 nm in size were located in the periplasmic space of bacterial cells. The dried biomass-supported palladium was applicable to a heterogeneous catalyst in a chemical reaction and an anode catalyst in a fuel cell for power production. Our methodology for the room-temperature synthesis of noble metal nanoparticles using the Fe(III)-reducing bacteria is an attractive green process that is cost-effective and environmentally benign.

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Monolithic and composite ceramic films of TiN, Ti-Al-N, Ti-B-C-N and PSZ were prepared at relatively higher deposition rate (approximately 100 nm/min) and at lower temperature (< 800°C) by a novel thermal plasma CVD designed to spray Ti-, Al-, B-, or Zr-alkoxide solutions into Ar/H₂/N₂ thermal plasma. Chemical compositions of composite films were controlled by changing of mixing ratios of two kinds of alkoxide solutions and N₂ flow rates. PSZ films were prepared by mild oxidation of Y- and Zr-alkoxide solutions with water introduced into the thermal Ar/N₂ plasma without oxidation of under layer TiN. Cutting tests of composite TiBCN films deposited on WC-Co cutting tools exhibited better wear resistance compared with commercial TiN coated cutting tools.

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To provide bioelectrets with controlled electrical energy, the polarization characteristics of stoichiometric and nonstoichiometric hydroxyapatite (HA) ceramics were investigated in terms of crystal structures using Rietvelt analysis technique. HA ceramics with and without hydroxide ion defects were prepared at 1250°C for 2 h under streaming steam (for stoichiometric HA; w-HA) and air (for hydroxide-deficient HA; a-HA). Polarization of ceramics was done at 400°C for 1 h under a 5 kVcm^-1 DC electrical field. Based on a result of thermally stimulated depolarization current (TSDC) measurement, the charge storage (Q) of polarized ceramics was significantly influenced by sintering atmosphere; Q value of a-HA was about 7 times larger than that of w-HA. Rietvelt analysis of XRD spectra suggests that a dipole formation of a-HA was probably due to the proton displacement form hydroxide ions to phosphate ions, while w-HA was likely polarized by proton migration between hydroxide ions. The dominant usage of phosphate ion as a proton localization site should contribute for the improvement of polarization property of a-HA.

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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 doped calcium phosphate powders were prepared by aqueous solution process. The crystal phase of obtained samples had a hydroxyapatite (HAp)-related structure with low crystallinity, and the crystallinity of samples decreased with increasing ratio of Fe (R_Fe). The crystallinity of samples improved by heat treatment more than 1073 K for 2 hours and α-Fe₂O₃ phase was generated as a second phase. The lattice parameter of HAp phase drastically changed at R_Fe=1 mol% caused by the difference of ion radius between Ca ion and Fe ion, and there was a trend of that the a-axis shrinks and c-axis expands by further increment of R_Fe. The obtained powders had granular crystals with 10 nm in diameter. All samples showed paramagnetic property, and the maximum magnetization was 3×10^-2 emu/g at R_Fe=5 mol%.

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Hydroxyapatite (HAP) possesses extremely high ability of bioactivity and ion exchange. In this study, hydroxyapatite containing amorphous silica was prepared by heat-treatment in air atmosphere for the mixture of hydroxyapatite and amorphous silica powders in order to develop the high performance modified hydroxyapatites. Their microstructures of the samples prepared by heat-treatment at various temperatures were examined by scanning electron microscopy (SEM) and their characterizations were evaluated with X-ray diffraction (XRD) and fourier transform infrared spectrophotometry (FT-IR) and so on. XRD results indicated that the incorporation of Si ion as a SiO₄^4- into PO₄^3- site arose the increase of lattice constants for hydroxyapatite structure. These results suggested that SiO₄⁴ was substituted to PO₄^3- site in HAP structures, leading to the successful synthesis of Si-incorporated hydroxyapatite.

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Photo-curable organoborosilicate glasses were synthesized through a catalyst- and solvent-free and non-aqueous alcohol condensation process at low temperature below 100°C. Formation of Si-O-B linkage was confirmed by IR spectra. After irradiation of UV-light, we have successfully cured the prepolymer coatings into prepared transparent and homogeneous thin film. A refractive index of the thin film of B(OH)₃: 3-Methacryloxypropyltrimethoxysilane=1:1 composition was measured by a prism coupling method n=1.515 at 633 nm. Moreover, pencil hardnesses according to JIS5400 of photo-cured thin film before and after heat treatment at 550°C were 6H and over 10H, respectively. We demonstrated fabrication of microstructures on transparent thin film by embossing process followed by photo curing.

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ZrO₂ ceramics containing CaO or MgO as an additive were fabricated by the spark plasma sintering (SPS) method and pressureless sintering (PS) method at 1300°C and 1500°C. Sintered samples were characterized by XRD and their microstructures were observed by SEM. Spark plasma sintering resulted in the successful fabrication of tetragonal ZrO₂ bulks with fully dense microstructures over 99 % of theoretical density, although ones prepared by the pressureless sintering (PS) method had the lower density of 93 %.

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