Carbon based or containing refractories has been attracting great attention because of their unique properties e.g. high thermal conductivity, low thermal expansion, high resistance to thermal shock and chemical inertness to the slag. They are classified into two groups; carbon/bricks/blocks and carbon containing materials. Carbon containing materials are further classified into carbon containing basic refractories and non-basic refractories. Manufacturing processes are considered. The properties e.g. physical, thermal, mechanical and chemical are reviewed. Antioxidant and bonding materials for these types of the refractory products are reviewed. Their applications are also considered.

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Hydrophobic coatings have been applied to various industrial items. However, their expected properties cannot always be obtained for practical use by merely decreasing their surface energies. Various cases require precise design and control of a coating's structure and chemical composition. This paper briefly reviews recent studies of transparent hydrophobic coating design. It specifically addresses superhydrophobic coatings.

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The oxide-ion conductivity of two solid-solution systems of a pyrochlore-type composition, (Y_1-xLa_x)₂(Ce_1-xZr_x)₂O₇ (YLa) and (Nd_1-xYb_x)₂(Ce_1-xZr_x)₂O₇ (NdYb), was investigated. The crystal phase of the YLa system with a variable cation radius ratio, r(A³⁺)/r(B⁴⁺), but a constant lattice parameter, changed from the rare-earth-C (C)-type phase to the pyrochlore (P)-type phase through the fluorite (F)-type phase with an increase in composition (x), depending on the cation radius ratio (i.e., a measure of ordering degree of oxygen vacancies). On the other hand, the NdYb system, with a variable lattice constant, but a constant cation radius ratio, showed the F-type phase in the entire composition range, except for Nd₂Ce₂O₇, which was assigned to the C-type phase. The local ionic arrangement speculated from the analysis of the Raman spectra of the two systems agreed with the results of X-ray diffraction (XRD) analysis. It was found by conductivity measurements that, when the lattice constant was constant in the whole system, oxide-ion conductivity decreased with increasing ordering of oxygen vacancies and when the ordering of oxygen vacancies was constant, the conductivity increased with increasing unit cell free volume.

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Mesoporous titania nanocrystals have been prepared via a surfactant-assisted templating method (SATM). The effect of key parameters, i.e., surfactant-removing condition, surfactant to alkoxide molar ratio, acetylacetone concentration, pH value, and water to alkoxide molar ratio, on the structural and morphological characteristics and photocatalytic activity of titania nanocrystals were investigated. The synthesized titania nanoparticles exhibited anatase-type mesoporous structure with surface area of up to 140 m²/g. High photocatalytic activity was obtained from the titania nanocrystals calcined at 300°C for 72 h, which was rather higher than that of ST-01, one of the most active photocatalyst commercially available.

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Ac conductivity (σ_ac) obtained from admittance of Eu₂Zr₂O₇ and La₂Ce₂O₇, which have pyrochlore- and fluorite-type structure, respectively, was measured as a function of frequency in the range between 5 Hz and 13 MHz and in the temperature range between 573 and 1073 K. The frequency dependence of the σ_ac of these oxide-ion conductors showed a remarkably different behavior from that of the cation ones. By comparison of the σ_ac with other conductivity data obtained by dc four-probe and impedance spectroscopic methods, it was found that the σ_ac in the frequency range below 10⁵ Hz was strongly influenced by space charge polarization at grain boundary and that the σ_ac obtained from high frequency plateau agreed with bulk conductivity, σ_ib, from impedance spectra and dc conductivity, σ_dc.

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Surface dissolution and diffusion of oxygen molecules (O₂) in SiO₂ glass were studied by their photoluminescence at 1272 nm excited with a titanium sapphire laser oscillating at 765 nm. The dissolution of O₂ from ambient atmosphere at both surfaces was much faster than the following diffusion of O₂ into SiO₂ glass, indicating that the surface dissolution is not the rate-limiting step for the saturation of SiO₂ glass with O₂. The time- and temperature-dependent concentration changes of O₂ allow to evaluate the diffusion coefficient and the saturation solubility of O₂ in SiO₂ glass.

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When a 355-nm pulsed laser light was focused on a polished surface of single crystal silicon (100) in an atmosphere of N₂ gas, some visible photoluminescent silicon nanocrystallites deposited at the bottom and in the vicinity of a hole produced by intense laser ablation. The emission band of these Si-particles, when excited with an Ar ion laser (λ=514 nm), had a maximum intensity at 590 nm (2.1 eV)-680 nm (1.8 eV) varying systematically in submillimeter units of their distance from the hole. Similar irradiation was carried out under two other gas atmospheres (Ar and O₂) and in vacuo (<1.33×10^-4 Pa) and the photoluminescent character of the deposited compounds were examined by microprobe photoluminescence spectroscopy. The luminescent characters (band shape and/or band peak position) were found to depend also on these gas atmospheric conditions.

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A novel approach to fabricate sub-μm scale arrays is demonstrated with the growth of rutile TiO₂ on titanium substrates. The fabrication process is template-free, simply involving coating of the titanium substrate with sodium tetraborate glass, Na₂O•2B₂O₃: when the glass coating was removed by dissolution in distilled water at 80°C for about 5 h, random or well-ordered submicron-scale rod arrays of rutile were left on the substrate. A glass phase topotaxial (GPT) nucleation and growth mechanism is thought to operate in the crystal growth process.

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Lanthanum-modified lead zirconate titanate (PLZT) ceramics possess a photostrictive effect that is applicable to photo-driven and wireless actuators. The photostrictive strain is expressed in a product of piezoelectric constant and photovoltage, and it is theoretically explained that a grain size reduction enhances photovoltage. Dense PLZT ceramics with grain size of 0.16-1.84 μm were obtained by sintering a mechanically alloyed (MA) powder. As the grain size decreased, the photostrictive strain increased and exhibited its maximum value of ≈1×10^-4, which is equivalent to electric-field-induced strain in common piezoelectric ceramics. This proved that a reduction of grain size is effective for the enhancement of photostrictive strain. Additionally, further improvement in photostrictive strain of the PLZT ceramics with fine grains could be predicted by performing a poling treatment at higher electric-fields.

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A practical method to prepare α-alumina bulk with excellent crystallinity, has been developed using fast CO₂ laser irradiation with a kaleidoscope, rather than extended heat treatment in a high temperature electric furnace. Amorphous alumina powder was synthesized by the chemical solution deposition method, using aluminum tri-sec-butoxide as a starting material. Laser irradiation of the amorphous powder without organic residues accelerated the crystallization of amorphous alumina to α-alumina and allowed the preparation of α-alumina in bulk and free from breakage. The α-alumina bulk was porous, and its thermal conductivity was at least 10 times less than the value reported for sintered α-alumina.

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