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Water retentivity is necessary to ceramics building materials for pavement and exterior to restrain heat island effect. However, this property tends to bring about a cold resistant fall at the same time. Therefore some size of pore were introduced into the structure of pavers for the purpose of permitting the volume expansion of the water by freezing in this study. It was suggested that pores of suitable size improved cold resistance of them.

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Hydroxyapatie (HAP: Ca10(PO4)6(OH)2) can adsorb harmful organic materials such as bacteria, while titanium oxide (TiO2) is one of excellent photocatalyst. In order to realize highly efficient adsorption/decomposition properties, HAP/TiO2 composite was prepared in this paper. Needle-like hydroxyapatite with high specific surface area and high crystallinity was successfully synthesized by the precipitation method using an autoclave and a microwave irradiation. The synthesized HAP showed more excellent adsorption ability to humic acid than commercial HAP. Besides, the HAP /TiO2(p-25) composite achieved high specific surface area and good decomposition property for humic acid.

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Nanoscale SiC particles were prepared by mechanical alloying used high-energy mechanical method in a SPEX 8000 shaker/mill. Si and C-black were mechanically alloyed with the condition of ball to charge ratio of 50:1, 40:1, 30:1, 20:1, 10:1 after 60 min milling within a high-purity argon filled glove box and heat treated at 1400^oC for 180 min in Ar. XRD and TEM have been used to characterize the product and the results showed increasing of charge ratio promoted the formation of SiC. Thus, the charge ratio can play an important role for obtaining nanocrystalline phase.

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We synthesized TiO₂ spherical particles by alkoxide method. Ultrasonic irradiation was performed before and during the synthesis. For comparison, TiO₂ spheres were also synthesized by mechanical stirring. Furthermore, the horn-type and the cleaner-type ultrasonications were compared. By using the cleaner-type sonication both before and during the synthesis, TiO₂ spheres of 1.2µm were obtained with monodispersity of D₉₀/D₁₀=0.82.

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A novel solid electrochemical surface machining of hard materials such as W, Mo and WC were performed using an oxide ion conductor. The fundamental solid electrochemical cell consists of an anode (W, Mo, WC) / pyramidal NiO-YSZ / cathode system, where the contact diameter between the materials and NiO-YSZ was extremely small.Under applying an electric field at high temperature, the substrate was electrochemically oxidized by reacting with O^2- at the target / NiO-YSZ microcontact, and then the produced metal oxide at the microcontact readily evaporated under a reduced pressure. As a result of continuous electrolysis, the substrate was locally consumed at the microcontact, and thus solid state electrochemical micromachining was accomplished.

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In this report, zinc oxide (ZnO) films were fabricated by using Spin Spray technique, which is consisted of spraying two kinds of solutions containing metal ion or oxidizing agent to revolving heated substrate. Though there are many advantages in this technique such as simple equipment, low-cost, low-temperature (< 100 degree C.) and high deposition rate etc..., it has almost only used to prepare spinel ferrite thin films. For the first time, Spin Spray technique was applied to prepare ZnO films.

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Itacolumite (flexible sandstone), which exists in nature, is composed of quartz grains and three-dimensional interlocking cracks among the grains similar to the jigsaw puzzle, and therefore it can freely move within a limited arc. In order to generate cracks, various composites were prepared by sintering mixtures of ceramics with different thermal expansion behavior. For example, some cracked composites, that were synthesized by sintering low thermal expansion KZr2(PO4)3 and high thermal expansion KAlSi2O6, showed somewhat ductile deformation similar to itacolumite. In this work, quartz grains or alumina grains were sintered with a secondary phase such as a glass, and then the cracking between grains was checked.

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Flexible ceramics with a high softness would be highly useful in stress relaxation and/or in thermal shock resistance. Natural flexible sandstone, itacolumite, has a pervasively cracked microstructure which allows some free motions between grains. Some cracked composites were prepared by sintering granular quartz or alumina with a secondary phase such as a glass phase. The synthesized composites were exhibited somewhat ductile deformation and interesting thermal and mechanical behaviors. The mechanism of this flexibility might be applied to refractory.

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Most of refractories continue to be used after cracks generate. However, since the generation of the crack is not treated generally in the FEM analysis of the refractory, it was not possible to estimate the condition after the cracks generate. We examined the application of low tension material model of the general-purpose FEM software to the analysis of the refractory. At first, the definition method of fracture characteristics was examined, and then the analysis of spalling test was carried out. Features of the cracks in the experiments were reproduced in the analytsis, and the effectiveness of this technique was clarified.

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Alumina bricks and AG (alumina-graphite) bricks, both of which had similarly modified grain size distributions of alumina and were fired at 1500degC, were prepared to investigate the effect of the grain size distribution on physical properties. The alumina bricks showed the highest bulk density when q value of the Andreasen's equation is 0.5, while the AG bricks exhibited a monotonous increase in bulk density with increasing q value. As for other properties, both the alumina bricks and the AG bricks showed similar tendency, but degree of dependence on the q value was much smaller in the AG bricks.

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