Microporous layered titanium phenylphosphonate, Ti(O₃PC₆H₅)₂ and sulfonated titanium phenylphosphonate, Ti(O₃PC₆H₄SO₃H)_0.89 (O₃PC₆H₅)_1.1·1.8H₂O were prepared in the presence of sodium dodecylsulfate (SDS). Interplanar spacing (d₀₀₁) of titanium phenylphosphonate is 1.43 nm and after sulfonation it increased to 1.64 nm. The surface area of titanium phenylphosphonate is 264m²g^-1.

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Aiming at lowering contact resistance between SOFC components, we produced an Air-Side Electrical Connector(ASEC) which deforms easily under compressive load at high temperature. The ASEC was prepared by soaking a cloth of a carbon fiber with a (La_0.85Sr_0.15)_0.85MnO₃(LSM) slurry and firing at 1200°C. The porous ASEC was then pressed at a temperature of 1500°C. It deformed easily, and its thickness changed to be 38%, 46%, and 58% of the pre-deformed one under a stress of 98 kPa, 49 kPa, and 20 kPa, respectively. Dense LSM bulks or (La_0.75Ca_0.30)Cr_0.95O₃ (LCC) bulks were bonded with the ASEC as an intermediate material at 1500°C. The contact resistances at 1000°C in air between the LSM and the ASEC, and between the LCC and the ASEC were 1.1mΩcm² and 4.2mΩcm², respectively, at the bonding condition of 98kPa. The difference was attributed to the formation of a new perovskite phase which has high electrical resistance at the interface between the LCC and the ASEC. However, the estimated I-R drop at the contact of LSM/LCC under the cell current density of 0.3 A cm^-2 was 4 mV, an efficiently low value for practical use.

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Textured γ-Na_xCoO_{2 - δ} ceramics have been prepared by both templated grain growth (TGG) and reactive templated grain growth (RTGG) methods using single-crystalline particles of γ-Na_xCoO_{2 - δ} as templates. An XRD analysis indicated that the samples were highly c-axis oriented; i.e., the highest Lotgering’s factor was estimated to be 0.93. According to transport property measurements, the highly textured γ-Na_xCoO_{2 - δ} sample exhibited electrical conductivity (σ) = ∼1.85 × 10⁴ S/m, Seebeck coefficient (S) = ∼137 μV/K and power factor (PF ≡ σ·S²) = 0.35 mW·m^-1·K^-2 at ∼800 K. These values of σ and S are smaller than those of single crystals (sc) ; that is, σ_sc = 19.2 × 10⁴ S/m and S_sc = 200 μV/K at 800 K. The magnitude of σ was found to decrease in proportion to the relative density (d) of the sample, while S was independent of d. Furthermore, both σ and S seemed to be sensitive to the Na content of the samples. Both the low density(d∼70%) and the deviation from the optimal Na content were considered to be predominant factors for the low thermoelectric properties of the present textured samples.

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The mobility of positively and negatively charged alumina particles in concentrated suspensions was analyzed with monitoring the electrical conductivity of the suspensions. The decreased mobility (u) at a lower charge (Q) was due to increased attractive interaction. The increase of volume fraction of moderately charged particles resulted in the decrease of u value because of the increased repulsive interaction with decreased interparticle distance. Too strong repulsive interaction between highly charged particles suppressed the migration of dispersed particles. The mobility of negatively charged particles was lower than that of positively charged particles at a similar Q value because of a stronger effect of chemical bonding between hydrated particle surface. The apparent viscosity of acidic suspensions was lower than that of basic suspensions. This result was also discussed based on three important effects of charge, concentration and nature of hydrated surface of alumina particles. The green densities of alumina compacts consolidated by filtration through gypsum molds were higher for the acidic suspensions than for the basic suspensions.

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Na_{1 + x}Co₂O₄ ceramics were prepared by spark plasma sintering (SPS) and their thermoelectric properties were investigated from room temperature to 700°C in air. The SPS process with cover pellets technique is effective in obtaining highly densified single phase Na_{1 + x}Co₂O₄ ceramics, typically 98% of the theoretical X-ray density, with lower resistivity. The power factor and figure of merit of the SPS treated NaCo₂O₄ ceramics attain 8.4 × 10^-4 W·m^-1·K^-2 and ZT = 0.3 at 700°C, respectively.

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This work focused on granite-SUS pipe-dry steam interaction in the presence of copper. Three types of hydrothermal experiments were conducted: 1) SUS-Cu-granite, 2) SUS-Cu, 3) SUS-granite. It was found that a high protective amorphous AlSi_1.6O₄ layer (thickness about 5 μm) formed on the supporting pipe surface only in the case of SUS-Cu-granite interaction. The formed layer was characterized by X-ray diffraction (XRD) techniques and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray (EDX) device. According to kinetics data this layer was confirmed to have highly protective properties.

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Synthesized through sol-gel processing were Ormosil type hybrid gels containing varied mass fractions of colloidal silica, poly (dimethylsiloxane) (PDMS), tetraethoxysilane (TEOS) and calcium nitrate. Viscoelasticity, mechanical strength and ²⁹Si MAS NMR spectra were measured, and in vitro apatite deposition in a simulated body fluid (SBF) of the Kokubo recipe was examined. The relative height of a T_g peak at about −100°C in tan δ versus temperature curves grew with the colloidal silica content. This peak growth was accounted for the relative increase in PDMS-colloidal silica interactions. As the increase in the compressive strength followed the increase in colloidal silica content, the number of PDMS-silica bonds and hydrogen bond of colloidal silica increased due to the NMR spectra and tan δ curve. Thus, mechanical strength was dependent on PDMS-silica bonds and the hydrogen bond of colloidal silica. On the other hand, as the relative PDMS content increased, the number of PDMS-silica bonds was little influenced while PDMS chain structure increased. The gel (with a molar ratio TEOS : PDMS : H₂O : HCl : Ca(NO₃)₂·4H₂O = 1 : 0.48 : 5.0 : 0.9 : 0.10) containing 14 mass% colloidal silica (CS₁₄P_0.48Ca_0.10) exhibited the highest maximum failure strain (about 70%) among all samples. Thus, the relative content of PDMS chain structure depending on PDMS content influenced the maximum failure strain. CS₁₄P_0.48Ca_0.25 could not deposit apatite within 7 d after soaking in SBF, while PDMS/TEOS = 0.24 (molar ratio) could deposit apatite within 3 d. The increase in PDMS content restrained the dissolution of Ca ions.

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The strengthening mechanism of 12 mol% CeO₂-doped tetragonal zirconia polycrystals (12Ce-TZP) after reduction at 600 to 1000°C in hydrogen gas was investigated from the viewpoints of crystal phase, hardness, bending strength and residual stress by X-ray analysis. Weight loss as well as color change were recognized in the reduced Ce-TZP, where oxygen release was caused by the reduction of Ce⁴⁺ to Ce³⁺. In the tetragonal phase after reduction heat treatment, the tetragonality decreased and the lattice volume increased by 1%, which is due to the increase in ionic radius of Ce⁴⁺ to Ce³⁺. The highest hardness value of 12.8 GPa was obtained on the surface of an entirely reduced 12Ce-TZP. When only the surface layer was reduced by heat-treatment for short time, the 12Ce-TZP specimen showed a maximum bending strength of 750 MPa, higher than as-received specimen by approximately 40%. No stress induced transformation from tetragonal to monoclinic phase was observed near the surface of reduced 12Ce-TZP after bending test. A good correlation between bending strength and residual stress in tetragonal phase evaluated by X-ray stress measurement, was confirmed. A residual compressive stress of approximately 400 MPa was introduced in the surface of the most strengthened specimen. Partial reduction of 12Ce-TZP under selected conditions introduced residual compressive stress in a surface layer of the polycrystals and led to strengthening of the ceramic. In this work, the authors proposed a novel mechanism of “reduction-induced strengthening (RIS)” in CeO₂ containing ceramics.

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The glass-ceramics of the phosphorus induced Na₅RSi₄O₁₂ (N5)-type (R = Y, Sm) Na⁺ superionic conductors in the systems Na₂O-Sm₂O₃-P₂O₅-SiO₂ and Na₂O-Y₂O₃-Sm₂O₃-P₂O₅-SiO₂ were prepared by crystallization of glasses with compositions Na_{3 + 3x - y}Sm_{1 - x}P_ySi_{3 - y}O₉ and Na_{3 + 3x - y}Y_{(1 - x)/2}Sm_{(1 - x)/2}P_ySi_{3 - y}O₉, respectively. The optimum conditions for crystallization were discussed with reference to the conduction properties and the preparation of uncracked N5-type glass-ceramics. The crystallization of the N5 single-phase glass-ceramics was dependent strongly on the concentrations of both[R] and [P] (or x and y in the composition parameters) and the temperature for crystallization of glass specimens. Grain growth was promoted with the increasing heating temperature and heating time for crystallization. The Na⁺ ionic conductivities of the glass-ceramic Na_4.1Sm_0.5P_0.4Si_2.6O₉ and Na_4.1Y_0.25Sm_0.25P_0.4Si_2.6O₉ were 4.78 × 10^-2 and 2.79 × 10^-2 S/cm at 300°C, respectively.

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20 vol% titanium nitride ink was prepared, and printed directly by ink jet printing. The effect of the ink characteristics was studied on both printing and forming behaviors. An ink jet printer of the air jet system was employed which could eject high viscosity ink. In order to improve the stability of the ink, poly carboxyl ammonium (PCA) and microcrystalline cellulose (MC) were found to be the proper additives to the suspension. As a result, it was possible to prepare the ink with various characteristics by adding PCA and MC. The control of the ink characteristics was found to be the key concept in adjusting printing ejection and compact characteristics. As the apparent viscosity of the ink increases, the weight of printing ejection decreased, and the thickness of printed compact also thinned.

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Temperature dependence of the electrical resistivity of the Al₄SiC₄ sintered bodies in the range of 100-1000°C was studied in this paper. Current-voltage characteristics of the bodies showed a linear relationship, and the characteristics have an ohmic region. Electrical resistivity, obtained from the current-voltage characteristics, exhibited insulation properties, and decreased with the porosity of the bodies. Further, the electrical resistivity varied significantly with temperature. However, any difference in activation energy for electrical resistivity among samples was rarely found despite the different porosity of them. Consequently, the porosity of the bodies did not affect the temperature dependence of electrical resistivity.

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In this paper, we discussed the effect of isostatic pressure on the green density and sintering properties of green compact of BaTiO₃ ultrafine particles with stoichiometric composition, prepared by sol-gel method. Fine powder compacts were formed by high pressure cold isostatic pressing ranging from 0.05 to 0.90 GPa for 2 min. The particle diameter of fine powder, derived from Ba(OH)₂ aqueous solution and titanium alkoxide, was controlled by calcination at 700°C for 2h. Ultra-high isostatic pressure at 0.90 GPa led to closed packing green bodies of ultrafine BaTiO₃ particles. The maximum density of 68% was reached in green compacts of BaTiO₃ particles, which were calcined at 700°C and whose particle size increased to 59nm in diameter. On the other hand, in the case of as-dried BaTiO₃ particles at 200°C, with no calcination and whose particle size was about 19nm in diameter, the relative density was almost equal to that of calcined particle after exposure to a relatively low isostatic pressure, ranging from 0.05 to 0.19 GPa. However, the relative density of as-dried powder compact was higher than that of calcined powder compacts by using isostatic pressure > 0.19 GPa, and the maximum density of green compact was 81% of theoretical by using a ultra-high isostatic pressure of 0.90 GPa. Densification of green compacts of as-dried BaTiO₃ particles in the high-pressure range might mainly occur by viscous deformation at the contact points between ultrafine particles. Green compacts were sintered in the range 700 to 1100°C for 2h. Closely packed green compacts of BaTiO₃ particles could be sintered to a density > 96% of theoretical at relatively low temperature.

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There is growing interest in applying an r-GRIN lens to small and simple optical systems, so that the refractive index difference, Δn, of the r-GRIN lens is ≥ 0.04. In this study, a sol was prepared, which had high concentration of barium, using a planetary mixer in order to expand the Δn of the r-GRIN glass. Sol preparation and wet gel treatment conditions were examined using Quality Engineering, which is one of the available statistical analysis methods. According to this method, the optimum conditions could be located. r-GRIN glasses with low distributed dispersion, Δn of 0.035, and a resolution of 100 lines per 1mm could be prepared. Furthermore, we succeeded in expanding the Δn value up to nearly 0.05 by increasing the volume of the concentration distribution solvent.

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Aiming at obtaining a thinner electrode layer, Ni powder of 0.2μm grain size was used and BaTiO₃ particles of either 30 nm or 50 nm in size were added. The results indicate that when BaTiO₃ nanoparticles with good dispersibility are added to Ni powder of 0.2μm, it is possible to suppress sintering of the Ni electrode paste film by adding BaTiO₃ particles of 30 nm size, compared to the film using paste without any addition or with 50 nm BaTiO₃ particles. This was clarified from the results of the firing shrinkage rate and the fine structure of the sintered surface.

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Mechanical properties of porous anisotropic silicon nitrides, fabricated by a partial sinter-forging technique, were investigated in the temperature range from room temperature (R.T.) to 1400°C. The fabricated specimens, with porosity of about 24%, exhibited a relatively high strength as well as a high fracture energy. These good properties were maintained even at temperatures as high as 1300°C. This achievement of good properties is very likely due to the combined effects of grain alignment, presence of pores between grains and yttria sintering aid refractoriness.

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Third-order optical nonlinearities in three types of Au/dielectric composite thin films (Au/SiO₂, Au/Al₂O₃, and Au/TiO₂ films) with high concentrations (∼27 at.%) of Au particles (5.6-16.8 nm in diameter) have been investigated by means of Z-scan and pump-probe techniques in the femtosecond time region. In the optical-absorption spectra of the films, the absorption peak of the surface plasmon resonance (SPR) of Au particles was clearly observed. The peak was shifted toward a longer wavelength with increasing the refractive index of the dielectric matrices. Near the SPR peak, the imaginary part of the third-order nonlinear susceptibility, |Im[χ⁽³⁾]|/α, of the Au/SiO₂, Au/Al₂O₃, and Au/TiO₂ films increased in that order, due to the local field enhancement.

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