Microlens formation, as induced by single shot of a femtosecond laser pulse, was observed in Sm-doped non-crystalline SrS-Ga₂S₃ thin films. The existence of Sm²⁺ could be related to the photoinduced deformation of the thin films. The confocal scanning laser microscopy observations revealed that detachment in the thin films occurred locally at the center part of the irradiated area.

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In this paper, surface stresses are estimated by means of sliding scratch and spherical indentation tests to understand the surface fracture of alumina specimens with respect to grain size. The critical load for material failure and the friction coefficient determined from scratch test are used for the estimation of surface stresses by finite-element analysis. In spherical indentation test, the size of the Hertz crack measured is proportional to the surface stress on cracking and hence the crack diameter can indicate the tensile stress on the surface of the specimen. Also, the radial tensile stress values are estimated using the critical load evaluated from the formation of circular ring crack. A similar trend of tensile stress degradation with increasing grain size is observed in both surface tests.

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In order to improve the environmental resistance of a polymer-derived SiC-fiber-reinforced SiC matrix composite (SiC/SiC composite), allylhydridopolycarbosilane (AHPCS) was utilized as the matrix precursor with Tyranno-SA^TM fiber. AHPCS showed higher densification efficiency in both intra- and interbundle areas than polycarbosilane (PCS). This may be due to its superior rheological characteristics and mass yield. For fabricating a high-performance composite, the effects of main processing factors, such as the number of densification processing, SiC particle content in consolidation slurry and curing processing, on porosity and microstructure were systematically investigated. According to the flexural tests performed for heat-treated composites, it was suggested that the AHPCS-derived composite was inferior to the PCS-derived one in oxidation resistance. On the other hand, the AHPCS-pyrolyzed product showed superior thermal stability in air at elevated temperatures to the PCS-pyrolyzed one. With this evidence, the interfacial structure formed with the AHPCS slurry-derived matrix was found to be the main reason for the deteriorating oxidation resistance of the AHPCS-derived composite. Thus the importance of a hermetic interfacial layer for improving environmental resistance was implied.

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Gallium sulfide glasses were prepared in the RS-Ga₂S₃ (R=Ca, Sr, Ba) systems. Respective glass forming regions are 67.5-70.0 mol% CaS, 63.8-68.8 mol% SrS and 60.0-73.8 mol% BaS. Transmission spectra in the visible region, refractive index and glass transition and onset crystallization temperatures were measured for representative compositions of SrS- and BaS-Ga₂S₃ transparent glasses. Raman spectroscopy reveals that RS-Ga₂S₃ glasses consist of the network of GeS₄ tetrahedra due to the RS addition. The compositional dependence of molar volume indicates a plateau region at 65-70 mol% RS in SrS- and BaS-Ga₂S₃ glasses. The morphology of sulfur complex anions in RS-Ga₂S₃ glass melts is discussed using the sulfur-to-gallium ratio as a variable parameter. The combined results suggest that well-developed glass networks are formed near 66.7 mol% RS (S/Ga=2.5) in the SrS- and BaS-Ga₂S₃ systems.

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Microwave sintering of Pb(Zr, Ti)O₃, PZT, based ceramics was investigated using multimode heating at 2.45 GHz and 30 GHz and compared to conventional thermal processing. For both PZT-5 and PZT-5H “soft” piezoelectric ceramics, microwave processing resulted in a reduction of sintering temperature by more than 150K. Of significance to the production of high surface area lead-based components, minimal PbO volatility was detected for samples processed as high as 1200°C. In contrast to conventionally processed PZTs, minimal grain size dependency of the dielectric and piezoelectric properties was observed.

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Synthesized were organically modified silicate (ORMOSILs) hybrids containing colloidal silica as an ingredient, starting from poly (dimethylsiloxane) (PDMS), tetrathoxysilane (TEOS) and calcium nitrate through sol-gel processing. The effects of pre-hydrolysis of TEOS on mechanical strength and viscoelasticity were examined. A sample of composition PDMS/TEOS = 0.60 (molar ratio) with pre-hydrolysis of TEOS showed about 65% maximum failure strain. Thus obtained hybrid exhibited a peak at around −75°C in the storage modulus-temperature curve of the hybrid, due to transverse movements of the PDMS chains. This hybrid, heated at 200°C deposited apatite within 1 d in the simulated body fluid of the Kokubo recipe.

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Stability and proton conductivity of AlH₂P₃O₁₀ · nH₂O(n = 2-3) were investigated in the temperature range from 75°C to 150°C under various water vapor pressure. The hydrolysis from AlH₂P₃O₁₀ · nH₂O to Al(H₂PO₄)₃ started at 100°C under a relative humidity (RH) of 60%, and further hydrolysis to AlPO₄ took place with increasing temperature and humidity. At 75°C, the original phase was maintained under saturated water vapor pressure. Conductivity measurements at 75°C (0% ≤ RH ≤ 98%) and 100°C (0% ≤ RH < 60%) indicated an abrupt increase in conductivity with increasing water content n in the range of n = 1.0 to 2.0 at both temperatures. The proton conductivity achieved a value σ = 5.0 × 10^-3S · cm^-1 at 75°C and 98% RH. It is assumed that the proton conductivity in the crystal became larger by formation of continuous hydrogen-bonding in AlH₂P₃O₁₀ · nH₂O.

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This paper reports on the relationship between the molecular structure of polymer dispersants, the electrosteric interaction of dispersants on a solid surface, and the viscosity of a ceramic suspension. Ammonium polycarboxylate with a different hydrophilic to hydrophobic group ratio (m : n) was prepared and added to a dense silicon carbide slurry (35 vol%). The steric interaction and adsorbed structure of the dispersant on silicon carbide powder were examined by means of an atomic force microscope (AFM). An optimum hydrophilic to hydrophobic group ratio, which was obtained from the maximum repulsive force and the minimum viscosity of the suspension, was determined to be m : n = 10 : 90. Furthermore, the optimum suspension behavior for obtaining an uniform green body structure by slip casting was evaluated and discussed.

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The microstructures of ceramics obtained by firing a pottery material blended with hollow ceramic microspheres of flyash origin to introduce closed pores into the ceramics were examined. The bulk density of the ceramics was found to decrease proportionally to the flyash balloon content, and it was slightly bigger than the apparent density when the firing temperature was set to 1260°C (standard temperature for firing the pottery material). The addition of flyash balloon resulted in the formation of both open and closed pores in the ceramics. The open pore ratio increased linearly with flyash content up to 57 vol%, and the ratio upturned further above 57%. The closed pore ratio increased approximately with the volume of the flyash balloons. The pore formation mechanism was investigated by scanning electron microscopy, energy dispersive X-ray analysis and X-ray diffraction measurements. The optimum firing temperature for achieving a well-vitrified body increased with decreasing potassium content due to the diffusion of potassium from the pottery material to the flyash balloons. Interspaces among the balloons contributed to the open pore volume at the balloon concentrations larger than 57 vol%. Light ceramics were successfully produced by firing at 1350°C which caused the sealing of the open pores.

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Chlorine-containing CaO-Al₂O₃-SiO₂ glasses were prepared. TG-DTA (thermogravimetry-differential thermal analysis) and TG-MS(thermogravimetry-mass spectrometric analysis) results showed that HCl gas was liberated from the glass above the temperature near glass transition. It was confirmed that chlorine in the glass reacts with water in the glass and in the atmosphere. It was considered that chlorine is replaced with oxygen in the atmosphere at the higher temperature. Glass transition temperature was found to decrease with introducing chlorine into the glass, suggesting that the glass structure was weakened by chlorine ions. The surface of glass containing chlorine has high reactivity with water and carbon dioxide in atmosphere.

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This paper reports about synthesis and fluorescence properties of Eu (II) doped vaterite phosphor emitting blue color by black light irradiation. Eu (III) doped vaterite phosphor was synthesized by a liquid phase reaction by adding 0.1 mol·dm^-3 (NH₄)₂CO₃ solution into 0.10 mol·dm^-3 CaCl₂ solution including EuCl₃ at 35°C. On the other hand, Eu²⁺ doped vaterite phosphor formed by heating mixture of Eu³⁺ doped vaterite and NH₄Cl. The upper limit of the incorporation of Eu³⁺ ion in vaterite structure was Eu/Ca atomic ratio of 0.01. Eu²⁺ doped vaterite phosphor could be also obtained by reduction of Eu³⁺ doped vaterite phosphor using NH₄Cl. Optimum synthetic conditions for Eu²⁺ doped vaterite phosphor with Eu/Ca atomic ratio 0.01 were: heating temperature of 350°C, time of 50 min and amount of NH₄Cl of 10 mass%. Emission wavelength of Eu²⁺ doped vaterite phosphor excited with 339 nm light was observed at about 427 nm and the emitted color was blue.

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The thermal conductivity and the temperature dependence of linear thermal expansion coefficient of Al₄SiC₄ sintered bodies were investigated from room temperature to 1200°C. Thermal conductivity decreased with the increase porosity. The thermal conductivity and linear expansion coefficient of highly densitied Al₄SiC₄ body in a range from room temperature to 1200°C were 80W·m^-1·K^-1 and 7.16 × 10^-6K^-1, respectively.

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Hollandite-type compounds, K_xNb_yT_{8 - y}O₁₆ (x ≤ 1.15, 0 ≤ y ≤ 1) were prepared by high temperature reaction under H₂ atmosphere. Black single crystals of Holladite-type K_1.15Nb_0.67Ti_7.33O₁₆ were obtained by heating a mixture of K₂CO₃, TiO₂ and Nb₂O₅ with the molar ratio of 1 : 1 : 1 under H₂ atmosphere at 1200°C for 1h. From single crystal X-ray diffraction analysis, the tetragonal lattice parameters of this compound are a = 1.02260(7) and c = 0.2974(1)nm, and the cystal structure refinement led to the final R-factors of R = 0.037 and R_w = 0.041 for 773 unique diffractions. The extent of solubility of niobium for powder samples was found to be y ≤ 1 in K_xTi_{8 - y}Nb_yO₁₆ from solid state reaction under H₂ atmosphere at 1200°C and the value of x ranged from 0.8 to 0.9.

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Composite materials have been prepared using a CO₂ solidification process from milling dust of autoclaved lightweight concrete (ALC; as matrix material), reinforced by addition of crushed glass (bottle) waste. The effect of varying glass collet size (0.08-5 mm) and glass volume (10-30%) on the fracture properties in the glass/ALC composite was examined by four point bending tests. For the glass/ALC composite cured under atmospheric conditions, we show, by conducting CO₂ solidification experiments at different CO₂ gas pressures (atmospheric, and 4-10 MPa), that the rate of reaction at the sample surface is faster under pressure, than under atmospheric conditions. At 4-10 MPa experimental conditions, a solidified ‘reaction rim’ is formed away from the sample surface characterized by the deposition of calcite, and a long internal fracture is created inside the sample, which reduces bending strength, although these characteristic features are not evident in samples cured at atmospheric conditions. Creation of the ‘reaction rim’ impedes further diffusion of CO₂ into the sample. Our results indicated that the CO₂ solidification of glass/ALC composite materials is best advanced under atmospheric conditions. The result also indicated that for <0.5 mm cullet size, the bending strength is enhanced, without being detrimental to fracture characteristics. However, increasing size of the crushed glass cullet (0.5mm-5mm) reduced the strength of the solidified composite. The interface between the ALC powder matrix and glass cullet was weak, and a fraction glass cullets 0.08-0.5 mm size may be incorporated in the waste concrete matrix by as much as 30 vol%.

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Colloidal Pt nanoparticles, which contained 23% tetrahedral particles, 8% cubic particles, 49% other polyhedral particles, and 20% unidentified particles, were prepared through the reduction of Pt cations by dissolved H₂ in the presence of sodium polyacrylate (SPA). The Pt particles were supported on carbon black and heated at 260°C in N₂ flow. The prepared catalyst (Pt/C-SPA) contained 18% tetrahedral particles, 5% cubic particles, 29% other polyhedral particles, and 48% unidentified particles. Although the mean Pt particle size of Pt/C-SPA estimated by transmission electron microscopy (TEM) (9.1 nm) was larger than that of a conventional electrocatalyst (Pt/C-ref) (2.4 nm) for oxygen reduction reaction (ORR), the specific activities of Pt/C-SPA for ORR based on the particle size measured from the TEM image and on its electrochemical surface area were 1.8 and 1.6 times as high as those of Pt/C-ref, respectively.

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Mixtures of crystalline proton type zirconium phosphate, HZr₂(PO₄)₃, with M^INO₃ (M^I = Li, Na, K, Rb, Cs) and M^II(NO₃)₂ (M^II = Mg, Ca, Sr, Ba) were thermally treated at 700°C for 5 h, in order to investigate the immobilization of M^I and M^II. All M^I and M^II immobilized products gave X-ray diffraction (XRD) patterns attributable to M^IZr₂(PO₄)₃ and M^IIZr₄(PO₄)₆ with a NASICON-type structure, and had the same crystal state as HZr₂(PO₄)₃. The a-axis lattice constant of M^IZr₂(PO₄)₃ and M^IIZr₄(PO₄)₆ decreased monotonically with increasing the ionic radius of M^I and M^II, respectively, while the c-axis lattice constant increased. The electrical conductivity of M^IZr₂(PO₄)₃ and M^IIZr₄(PO₄)₆ sintered at 1400°C decreased with increasing the ionic radius of M^I and M^II, respectively. Leaching tests for M^IZr₂(PO₄)₃ and M^IIZr₄(PO₄)₆ were carried out at 160°C for 24 h in 1 mol·dm^-3-HCl. The leaching rate decreased with increasing ionic radius of M^I and M^II, except for the case of Rb and Cs in M^IZr₂(PO₄)₃ and Sr and Ba in M^IIZr₄(PO₄)₆.

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