This review briefly surveys, with an emphasis on the author’s works, porous monoliths tailored by liquid-phase synthesis. Porous structures ranging from mesopore to macropore regions are induced in sol–gel polymerizing systems, which yield various porous materials such as inorganic oxides, organic–inorganic hybrids, crosslinked polymers, and carbons. It should particularly be noted that the networks must be homogeneous enough to obtain monolithic materials with fine pore structures, and for this purpose, the chemical reactions must be carefully designed and controlled. With exemplifying alkoxy-derived sol–gel systems and controlled/living radical polymerization systems, pore formations and applications of resultant materials are demonstrated.

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We report here noticeable observations of low anodic polarization resistance in a Ni–YSZ with highly dispersed nanoporous-nanocomposite microstructure. Its area-specific polarization resistance is ∼0.38 Ω cm² at 550°C. In addition, its methane conversion kinetics is greatly faster than that of a conventional Ni–YSZ.

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Spherical BaTiO₃-coated Ag powders with dense structures were directly prepared by spray pyrolysis. Ag powder with 1 wt % BaTiO₃ has particles of 0.53 µm mean diameter. BaTiO₃ had good properties for coating Ag powders: it decreased the sintering of the Ag powder at temperatures between 700 and 900°C. Complete melting of pure Ag powder, forming dense Ag thick film, occurred at 700°C. Whereas at this temperature, partial melting of the 1 wt % BaTiO₃-coated Ag powder occurred, forming Ag thick film with a porous structure. The pure Ag thick film shrunk 45% at 900°C. However, the thick films formed from 1 and 5 wt % BaTiO₃-coated Ag powder had respective shrinkages of 31 and 21%, respectively at 900°C. The sheet resistances of the Ag thick films formed from the 1 wt % BaTiO₃-coated Ag powder were 7.54, 4.93 and 4.09 m Ω/sq at firing temperatures of 700, 800 and 900°C, respectively.

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In this paper, a fundamental theory of packing density for particles with different size distributions is derived using a statistical method. The use of this theory enables calculation of the packing density of a particle system because the packing density depends on the size distribution function. This theory can also be applied to the calculation of the density of a multi-component mixture system by considering its size distribution function.

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A method to synthesize indium nitride (InN) crystal by the reaction of InCl₃ with LiNH₂ under N₂ atmosphere was studied. InN was formed at the temperature ranging from 350 to 450°C under 0.1 MPa N₂ atmosphere. X-ray diffraction (XRD) pattern and transmission electron microscope (TEM) image indicated that synthesized InN was crystalline powder with a wurtzite structure. Band gap was determined by plotting (αhν)² vs. hν for direct transition and the value of 0.83 eV was obtained.

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Undoped and Mn-doped (1−x)BaTiO₃–xBi(Ni_1/2Ti_1/2)O₃ (x = 0.03–0.7) ceramics were synthesized by a conventional solid state route. X-ray diffraction patterns revealed that the crystal structure was a tetragonal perovskite at x = 0.03, a pseudo-cubic perovskite at x = 0.1 and 0.3, and mixed phases at x = 0.5–0.7. The dielectric and piezoelectric responses were ferroelectric at x = 0.03 and relaxor-like at x = 0.1–0.7. The polarization–electric field and strain–electric field responses were suppressed at the relaxor compositions, and the large-field piezoelectric constant was 25–40 pm/V at x = 0.3–0.7. As x increased, the temperature of the maximum dielectric constant decreased compared to the Curie temperature of BaTiO₃ at x ≤ 0.1, and then it increased and reached 325°C at x = 0.7. At x = 0.3–0.7, the dielectric constant was less temperature dependent. These results suggest that the samples may be suitable for high temperature capacitor application.

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In this study, the effect of heating sources on the temperature profiles of soda-lime silicate glass was investigated. Conventional heating created an extreme thermal gradient (the surface temperature > the interior temperature) when glass which is a poor thermal conductor was heated. As a result, an adequate soaking time depended on the thickness was required for the interior of the glass to become as hot as those surface. On the other hands, microwave heating which was employed to rapidly and homogenously heat the glass, showed an inverted temperature gradient that the surface temperature is cooler than the interior temperature of the glass. When using microwave energy, critical temperature (T_cri) at which the glass can be self-heat, was observed to be at 370°C. At this temperature, the heating rate which is the interior temperature of glass increased from 8 to 16°C/min. On a cross section of glass, the thermal gradient (ΔT_heating, the interior–the surface) and the heating rate of glass were successfully manipulated by introducing a hybrid heating method which combined microwave heating with conventional heating. The results were 0°C ≤ ΔT_heating ≤ 180°C and ∼3°C/s, respectively.

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The single-nanosizing of a ceramics by a top–down method was demonstrated using a “wet planetary bead-milling” method, which is the combination of bead milling and planetary milling. By using the planetary bead-milling, single-nanoparticles (about 2 nm) of BaZr_0.9Y_0.1O_3−α (BZY-91), which is one of the perovskite type oxides, was obtained with the combination of 0.05 mmφ zirconia beads as pulverization media and ethanol as dispersion media.

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In this paper, Ba_1−xSr_xTiO₃ (0 ≤ x < 1) crystals with different morphologies have been selectively synthesized via a facile hydrothermal route without any surfactants or templates. The as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and electron diffraction (ED). It was found that the KOH concentration played a key role in the control growth of Ba_1−xSr_xTiO₃ crystals, and the morphology of Ba_1−xSr_xTiO₃ (0 ≤ x < 1) crystals can vary from sphere-like, star-like, to dendritic shape.

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