The Pnma-Imma-I4/mcm phase transitions of SrZrO₃ have been successfully observed by measuring the variation of energies of phonon modes as a function of temperature. The squares of phonon mode frequencies, ω₀², exhibit a linear relation with temperature, T, on both sides of the phase transitions. An unusual value of -7 of the ratio of ∂(ω₀²)/∂T below and above the phase transition temperature between Pnma and Imma, was observed compared to the value of -2 expected from the mean field theory. The result can be accounted for in terms of coupling between an optical mode and strain.

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Four porous calcium phosphates (HAp, HAp/β-TCP, β-TCP, and α-TCP) were prepared using a ceramic foaming technique combined with a hydrothermal treatment. These porous calcium phosphates had enough pore size, high specific surface area, and high porosity (>80%) for the cell growth of osteoblast-like cells. The compositions of the porous calcium phosphates depended on the solution in hydrothermal treatment and the sintering temperature. The cell activities of MC3T3-E1 cells on porous HAp, HAp/β-TCP, and β-TCP were similar to that of monolayer cultivation as a control in MTT assay, ALPase activities, and the cell density.

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Six kinds of powder samples with a different particle size and its distribution have been prepared from coprecipitated precursors by light grinding followed by sieving, and calcined in air to form the barium ferrite (BaFe₁₂O₁₉) phase. Correlation between the particle morphology and Fe/Ba molar ratio or magnetic properties has been examined. The results indicated that the powders consisting of coarse particles (100-200 μm) exhibit a single phase of BaFe₁₂O₁₉, and a higher saturation magnetization and coercivity than the powders having fine particles or a wide size distribution. The optimized powders showed a high coercivity of 5.85 kOe and a saturation magnetization of 71 emu/g that are closed to the theoretical values.

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Silver particles generated by the evaporation-condensation method were deposited to form a film on a silica glass substrate. The films thus obtained consist of nano-sized silver particles. Nonlinear refractive index, γ and nonlinear absorption coefficient, β determined by using Z-scan technique were both negative, while γ in the literatures for the silver particles-dispersed-glass composites was positive. The absolute value of γ for the as-deposited samples was increased as absorption peak wavelength due to surface plasmon resonance became close to the laser wavelength used in the measurement. The particle size (D) dependence, especially D^-3 dependence of γ was clearly observed for the films which were prepared at different particle generation temperatures and annealed at 170°C, and consisted of particles of 26 to 46 nm in size. This dependence was explained in terms of the quantum confinement effect.

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The anti-gallings and wear resistances of SiO₂ particles coated with carbon were investigated by using a Falex (pin/vee block) friction machine, when they were added into lithium soap-lubricating grease as solid lubricants. The SiO₂ coated with carbon showed higher seizure loads and better wear resistances than graphite. The lubricating actions of these carbon-coated SiO₂ particles are due to their presences at the friction interface which decrease the direct contact between the friction surfaces,thus resulting in high seizure loads and wear resistances.

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Influence of sintering temperature on the strength and micro-structure were investigated on silicon nitride specimens fabricated by pressureless post-sintering process using low-purity silicon powder as raw materials. Densification of reaction-bonded silicon nitride with sintering aid did not proceed further upon setting the post-sintering temperature at 1600 or 1650°C due to the volatilization of species and poor sinterbility. Sintering at 1850°C provided almost fully densified silicon nitride having an average strength of 521 MPa, the grains of this materials were relatively fine but did not develop into a rod-like shape.

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In order to study a glass plate strength against loading by explosion, stress generation of 300 mm×300 mm×19 mm float glass by blast wave loading was investigated by using a vertical square shock tube. Blast wave was produced by a vertical shock tube with an improved high-pressure chamber by inserting a cone-shaped material. Stress generation after maximum value upon blast wave was dependent on the decay pattern of blast wave loading. Stress generation σ(t, d*) at time t and normalized non-dimensional thickness d* by blast wave loading can be shown as using as a function of time t, various parameters: dynamic coefficient, C_d, static coefficient, C_b, two factors ω and λ dependent on glass thickness, decay constant A and positive time of blast wave t_p: σ(t, d*)=C_d sin ωt•exp{−λ(t-π/2ω)}+C_b{1−(t-π/2ω)/t_p}•exp{−A(t−π/2ω)/t_p}with an additional decay term to blast wave equation due to shock tube loading. Further, it is suggested that shock wave loading and blast wave loading have almost similar influence on failure of glass.

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Composite powders of Fe³⁺-exchanged synthetic smectite and polypyrrole were prepared by using pyrrole vapor, and their layered structures were investigated by Fourier transform-infrared spectrophotometer (FT-IR), X-ray diffractometer (XRD) and Thermogravimeter-Differential thermal analyzer (TG-DTA). The results showed that chemical oxidative polymerization of the pyrrole occurred in the interlayer spaces between silicate layers; the increment of the polypyrrole depended on vapor phase reaction time. The amount of polypyrrole and interplanar spacing of the composite powders increased gradually, and it was concluded that two layers of polypyrrole formed on both sides of Fe³⁺ in each space. The rate determining step of the reaction was the absorption and the diffusion of the pyrrole into the interlayer spaces. By TG-DTA, it was found that the thermal stability of the polypyrrole in the composite powders improved, for the polypyrrole being strongly restrained from burning and pyrolyzing in nanoscale spaces between silicate layers. A part of the polypyrrole was carbonized when the composite powders was heated up in N₂ with gradually rising temperature. The laminated carbon influenced the structural change of silicate layers. An increment of carbonization suggested that the laminated polypyrrole changed into a precursor for carbon under suitable conditions.

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There is no standardized method in Japan for the estimation of impact strength for strengthened porcelain tableware. In many cases, a measurement is carried out by ASTM C368 using a pendulum formula impact tester. However, there are many unknown factors about statistical dispersion in impact strength values, and the relation between the number of tested samples and accuracy of measurement. In this experiment, the impact measurement was carried out using a large number of high strength porcelain tableware. The dispersion in impact strength values was confirmed to show a normal distribution statistics, and the relation between the number of samples and measurement accuracy was discussed. Furthermore, it was revealed that the impact strength value was also influenced by the shape and weight of the impact hammer head.

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Si₃N₄ ceramics were sintered at temperature range of 1550-1700°C in an air atmosphere furnace using an Al₂O₃ crucible, Si₃N₄ packing powder and Al₂O₃ filler. Si₃N₄ packing powder and Al₂O₃ filler tended to agglomerate. It was found that coarse SN-F2 packing powder was the best candidate when process cost was considered and Al₂O₃ powder larger than 1-2 μm did not agglomerate even at 1700°C. Additionally, an Al₂O₃ crucible filled with Si₃N₄ powder is deteriorated and cracked after only several times using. Nevertheless, Si₃N₄ ceramic could be sintered to full density reproducibly. However, its mechanical strength was not high enough, and both the strength and the deterioration of crucible should be further improved.

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Seven kinds of potassium rare earth silicate glasses, (K₂O)_35.7(RE₂O₃)_7.2(SiO₂)_57.1 (RE=Sm, Gd, Dy, Ho, Y, Er, Yb), were prepared by melting a mixture of K₂CO₃, RE₂O₃ and SiO₂. Density increased with increasing atomic weight of RE. An exothermic peak attributable to crystallization was observed in the range between 720 and 800°C. Powder X-ray diffraction analysis showed the formation of two distinct phases, KREO₂ and K₂SiO₃, above crystallization temperature. The conductivity of (K₂O)_35.7(Y₂O₃)_7.2(SiO₂)_57.1 glass was similar to those of K₅YSi₄O₁₂ ceramics with the same composition and (K₂O)₃₆(SiO₂)₆₄ glass not containing Y₂O₃.

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Natural potash feldspar was used in an attempt to synthesize leucite crystals. The conditions necessary for synthesizing leucite crystals were examined and the crystal morphology were investigated. In addition, the formation mechanisms of leucite crystals were discussed. When a mixture of Al₂(SO₄)₃: Potash feldspar: K₂SO₄=3:3:15 was heated at 1100°C for 3 h, 50-60 μm diameter leucite crystals formed. Potash feldspar was stable up to 1000°C by this synthetic method, therefore a heating temperature of 1100°C was needed to form leucite crystals.

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